diff --git a/src/core/core-backtrace.c b/src/core/core-backtrace.c
index 29fd4d8aa..9c81a85ff 100644
--- a/src/core/core-backtrace.c
+++ b/src/core/core-backtrace.c
@@ -149,7 +149,7 @@ weechat_backtrace_addr2line (int number, void *address, const char *symbol)
  */
 
 void
-weechat_backtrace ()
+weechat_backtrace (void)
 {
 #ifdef HAVE_BACKTRACE
     void *trace[BACKTRACE_MAX];
diff --git a/src/core/core-backtrace.h b/src/core/core-backtrace.h
index 5ef2b542e..a7a596a7a 100644
--- a/src/core/core-backtrace.h
+++ b/src/core/core-backtrace.h
@@ -22,6 +22,6 @@
 
 #define BACKTRACE_MAX 128
 
-extern void weechat_backtrace ();
+extern void weechat_backtrace (void);
 
 #endif /* WEECHAT_BACKTRACE_H */
diff --git a/src/core/core-command.c b/src/core/core-command.c
index 55f8efd6d..61e9a0605 100644
--- a/src/core/core-command.c
+++ b/src/core/core-command.c
@@ -3057,7 +3057,7 @@ command_help_list_commands (int verbose)
  */
 
 const char *
-command_help_option_color_values ()
+command_help_option_color_values (void)
 {
     return _("a WeeChat color name (default, black, "
              "(dark)gray, white, (light)red, (light)green, "
@@ -5740,7 +5740,7 @@ COMMAND_CALLBACK(print)
  */
 
 void
-command_proxy_list ()
+command_proxy_list (void)
 {
     struct t_proxy *ptr_proxy;
     const char *ipv6_status;
@@ -8292,7 +8292,7 @@ COMMAND_CALLBACK(window)
  */
 
 void
-command_init ()
+command_init (void)
 {
     struct t_hook *ptr_hook;
 
diff --git a/src/core/core-command.h b/src/core/core-command.h
index 20152bf0c..48ef94ef5 100644
--- a/src/core/core-command.h
+++ b/src/core/core-command.h
@@ -96,13 +96,13 @@ struct t_command_repeat
     int index;                         /* current index (starts at 1)       */
 };
 
-extern const char *command_help_option_color_values ();
+extern const char *command_help_option_color_values (void);
 extern void command_version_display (struct t_gui_buffer *buffer,
                                      int send_to_buffer_as_input,
                                      int translated_string,
                                      int display_git_version,
                                      int display_upgrades);
-extern void command_init ();
+extern void command_init (void);
 extern void command_startup (int plugins_loaded);
 
 #endif /* WEECHAT_COMMAND_H */
diff --git a/src/core/core-completion.c b/src/core/core-completion.c
index 9388c5f91..59eb5cb34 100644
--- a/src/core/core-completion.c
+++ b/src/core/core-completion.c
@@ -2227,7 +2227,7 @@ completion_list_add_eval_variables_cb (const void *pointer, void *data,
  */
 
 void
-completion_init ()
+completion_init (void)
 {
     hook_completion (NULL, "buffers_names", /* formerly "%b" */
                      N_("names of buffers"),
diff --git a/src/core/core-completion.h b/src/core/core-completion.h
index 4d81d787f..37e1b15d6 100644
--- a/src/core/core-completion.h
+++ b/src/core/core-completion.h
@@ -28,6 +28,6 @@ extern int completion_list_add_filename_cb (const void *pointer,
                                             const char *completion_item,
                                             struct t_gui_buffer *buffer,
                                             struct t_gui_completion *completion);
-extern void completion_init ();
+extern void completion_init (void);
 
 #endif /* WEECHAT_COMPLETION_H */
diff --git a/src/core/core-config-file.c b/src/core/core-config-file.c
index eb58b270a..35cdf4bc0 100644
--- a/src/core/core-config-file.c
+++ b/src/core/core-config-file.c
@@ -311,7 +311,7 @@ config_file_arraylist_cmp_config_cb (void *data,
  */
 
 struct t_arraylist *
-config_file_get_configs_by_priority ()
+config_file_get_configs_by_priority (void)
 {
     struct t_arraylist *list;
     struct t_config_file *ptr_config;
@@ -633,7 +633,7 @@ config_file_option_insert_in_section (struct t_config_option *option)
  */
 
 struct t_config_option *
-config_file_option_malloc ()
+config_file_option_malloc (void)
 {
     struct t_config_option *new_option;
 
@@ -4150,7 +4150,7 @@ config_file_free (struct t_config_file *config_file)
  */
 
 void
-config_file_free_all ()
+config_file_free_all (void)
 {
     while (config_files)
     {
@@ -4497,7 +4497,7 @@ config_file_add_to_infolist (struct t_infolist *infolist,
  */
 
 void
-config_file_print_log ()
+config_file_print_log (void)
 {
     struct t_config_file *ptr_config_file;
     struct t_config_section *ptr_section;
diff --git a/src/core/core-config-file.h b/src/core/core-config-file.h
index d806c817e..2f3488f3f 100644
--- a/src/core/core-config-file.h
+++ b/src/core/core-config-file.h
@@ -205,7 +205,7 @@ extern int config_file_set_version (struct t_config_file *config_file,
                                                                            struct t_hashtable *data_read),
                                     const void *callback_update_pointer,
                                     void *callback_update_data);
-extern struct t_arraylist *config_file_get_configs_by_priority ();
+extern struct t_arraylist *config_file_get_configs_by_priority (void);
 extern struct t_config_section *config_file_new_section (struct t_config_file *config_file,
                                                          const char *name,
                                                          int user_can_add_options,
@@ -340,7 +340,7 @@ extern void config_file_option_free (struct t_config_option *option,
 extern void config_file_section_free_options (struct t_config_section *section);
 extern void config_file_section_free (struct t_config_section *section);
 extern void config_file_free (struct t_config_file *config_file);
-extern void config_file_free_all ();
+extern void config_file_free_all (void);
 extern void config_file_free_all_plugin (struct t_weechat_plugin *plugin);
 extern struct t_hdata *config_file_hdata_config_file_cb (const void *pointer,
                                                          void *data,
@@ -353,6 +353,6 @@ extern struct t_hdata *config_file_hdata_config_option_cb (const void *pointer,
                                                            const char *hdata_name);
 extern int config_file_add_to_infolist (struct t_infolist *infolist,
                                         const char *option_name);
-extern void config_file_print_log ();
+extern void config_file_print_log (void);
 
 #endif /* WEECHAT_CONFIG_FILE_H */
diff --git a/src/core/core-config.c b/src/core/core-config.c
index 2c1541a24..c67dd6284 100644
--- a/src/core/core-config.c
+++ b/src/core/core-config.c
@@ -433,7 +433,7 @@ config_check_config_permissions (const void *pointer, void *data,
  */
 
 void
-config_change_save_config_layout_on_exit ()
+config_change_save_config_layout_on_exit (void)
 {
     if (gui_init_ok && !CONFIG_BOOLEAN(config_look_save_config_on_exit)
         && (CONFIG_ENUM(config_look_save_layout_on_exit) != CONFIG_LOOK_SAVE_LAYOUT_ON_EXIT_NONE))
@@ -766,7 +766,7 @@ config_change_buffer_time_same (const void *pointer, void *data,
  */
 
 void
-config_compute_prefix_max_length_all_buffers ()
+config_compute_prefix_max_length_all_buffers (void)
 {
     struct t_gui_buffer *ptr_buffer;
 
@@ -785,7 +785,7 @@ config_compute_prefix_max_length_all_buffers ()
  */
 
 void
-config_set_nick_colors ()
+config_set_nick_colors (void)
 {
     if (config_nick_colors)
     {
@@ -864,7 +864,7 @@ config_change_look_nick_color_force (const void *pointer, void *data,
  */
 
 void
-config_set_eval_syntax_colors ()
+config_set_eval_syntax_colors (void)
 {
     if (config_eval_syntax_colors)
     {
@@ -1656,7 +1656,7 @@ config_day_change_timer_cb (const void *pointer, void *data,
  */
 
 void
-config_weechat_init_after_read ()
+config_weechat_init_after_read (void)
 {
     int context;
 
@@ -2011,7 +2011,7 @@ config_weechat_debug_get (const char *plugin_name)
  */
 
 void
-config_weechat_debug_set_all ()
+config_weechat_debug_set_all (void)
 {
     struct t_config_option *ptr_option;
     struct t_weechat_plugin *ptr_plugin;
@@ -3231,7 +3231,7 @@ config_weechat_key_delete_option_cb (const void *pointer, void *data,
  */
 
 int
-config_weechat_init_options ()
+config_weechat_init_options (void)
 {
     int context;
     char section_name[128];
@@ -5592,7 +5592,7 @@ config_weechat_init_options ()
  */
 
 int
-config_weechat_init ()
+config_weechat_init (void)
 {
     int rc;
     struct timeval tv_time;
@@ -5655,7 +5655,7 @@ config_weechat_init ()
  */
 
 int
-config_weechat_read ()
+config_weechat_read (void)
 {
     int rc;
 
@@ -5678,7 +5678,7 @@ config_weechat_read ()
  */
 
 int
-config_weechat_write ()
+config_weechat_write (void)
 {
     return config_file_write (weechat_config_file);
 }
@@ -5688,7 +5688,7 @@ config_weechat_write ()
  */
 
 void
-config_weechat_free ()
+config_weechat_free (void)
 {
     config_file_free (weechat_config_file);
 
diff --git a/src/core/core-config.h b/src/core/core-config.h
index 34ff85b41..889219d3a 100644
--- a/src/core/core-config.h
+++ b/src/core/core-config.h
@@ -416,20 +416,20 @@ extern struct t_hashtable *config_hashtable_completion_partial_templates;
 extern char **config_hotlist_sort_fields;
 extern int config_num_hotlist_sort_fields;
 
-extern void config_set_nick_colors ();
+extern void config_set_nick_colors (void);
 extern struct t_config_option *config_weechat_debug_get (const char *plugin_name);
 extern int config_weechat_debug_set (const char *plugin_name,
                                      const char *value);
-extern void config_weechat_debug_set_all ();
+extern void config_weechat_debug_set_all (void);
 extern int config_weechat_buffer_set (struct t_gui_buffer *buffer,
                                       const char *property, const char *value);
 extern int config_weechat_notify_set (struct t_gui_buffer *buffer,
                                       const char *notify);
 extern void config_get_item_time (char *text_time, int max_length);
 extern int config_weechat_get_key_context (struct t_config_section *section);
-extern int config_weechat_init ();
-extern int config_weechat_read ();
-extern int config_weechat_write ();
-extern void config_weechat_free ();
+extern int config_weechat_init (void);
+extern int config_weechat_read (void);
+extern int config_weechat_write (void);
+extern void config_weechat_free (void);
 
 #endif /* WEECHAT_CONFIG_H */
diff --git a/src/core/core-debug.c b/src/core/core-debug.c
index feee8a757..3f8326c5a 100644
--- a/src/core/core-debug.c
+++ b/src/core/core-debug.c
@@ -93,7 +93,7 @@ long long debug_long_callbacks = 0;    /* callbacks taking more than        */
  */
 
 void
-debug_build_info ()
+debug_build_info (void)
 {
     /* display version and compilation date/time */
     string_fprintf (
@@ -343,7 +343,7 @@ debug_windows_tree_display (struct t_gui_window_tree *tree, int indent)
  */
 
 void
-debug_windows_tree ()
+debug_windows_tree (void)
 {
     gui_chat_printf (NULL, "");
     gui_chat_printf (NULL, _("Windows tree:"));
@@ -355,7 +355,7 @@ debug_windows_tree ()
  */
 
 void
-debug_memory ()
+debug_memory (void)
 {
 #ifdef HAVE_MALLINFO2
     struct mallinfo2 info;
@@ -501,7 +501,7 @@ debug_hdata_map_cb (void *data,
  */
 
 void
-debug_hdata ()
+debug_hdata (void)
 {
     int count;
 
@@ -519,7 +519,7 @@ debug_hdata ()
  */
 
 void
-debug_hooks ()
+debug_hooks (void)
 {
     int i;
 
@@ -653,7 +653,7 @@ debug_hooks_plugin_types (const char *plugin_mask, const char **hook_types)
  */
 
 void
-debug_infolists ()
+debug_infolists (void)
 {
     struct t_infolist *ptr_infolist;
     struct t_infolist_item *ptr_item;
@@ -817,7 +817,7 @@ debug_libs_cb (const void *pointer, void *data,
  */
 
 void
-debug_directories ()
+debug_directories (void)
 {
     char *extra_libdir, str_temp[1024];
 
@@ -1026,7 +1026,7 @@ debug_unicode (const char *string)
  */
 
 void
-debug_init ()
+debug_init (void)
 {
     /*
      * hook signals with high priority, to be sure they will be used before
@@ -1042,6 +1042,6 @@ debug_init ()
  */
 
 void
-debug_end ()
+debug_end (void)
 {
 }
diff --git a/src/core/core-debug.h b/src/core/core-debug.h
index 151277de8..7bd47fb11 100644
--- a/src/core/core-debug.h
+++ b/src/core/core-debug.h
@@ -26,22 +26,22 @@ struct t_gui_window_tree;
 
 extern long long debug_long_callbacks;
 
-extern void debug_build_info ();
+extern void debug_build_info (void);
 extern void debug_sigsegv_cb (int signo);
-extern void debug_windows_tree ();
-extern void debug_memory ();
-extern void debug_hdata ();
-extern void debug_hooks ();
+extern void debug_windows_tree (void);
+extern void debug_memory (void);
+extern void debug_hdata (void);
+extern void debug_hooks (void);
 extern void debug_hooks_plugin_types (const char *plugin_name,
                                       const char **hook_types);
-extern void debug_infolists ();
-extern void debug_directories ();
+extern void debug_infolists (void);
+extern void debug_directories (void);
 extern void debug_display_time_elapsed (struct timeval *time1,
                                         struct timeval *time2,
                                         const char *message,
                                         int display);
 extern void debug_unicode (const char *string);
-extern void debug_init ();
-extern void debug_end ();
+extern void debug_init (void);
+extern void debug_end (void);
 
 #endif /* WEECHAT_DEBUG_H */
diff --git a/src/core/core-dir.c b/src/core/core-dir.c
index fe913ad95..c3cd44677 100644
--- a/src/core/core-dir.c
+++ b/src/core/core-dir.c
@@ -64,7 +64,7 @@
  */
 
 char *
-dir_get_temp_dir ()
+dir_get_temp_dir (void)
 {
     char *tmpdir;
     struct stat buf;
@@ -380,7 +380,7 @@ end:
  */
 
 int
-dir_create_home_temp_dir ()
+dir_create_home_temp_dir (void)
 {
     char *temp_dir, *temp_home_template, *ptr_weechat_home;
     int rc, add_separator;
@@ -599,7 +599,7 @@ error:
  */
 
 int
-dir_find_home_dirs ()
+dir_find_home_dirs (void)
 {
     char *ptr_home, *ptr_weechat_home, *config_weechat_home;
     char *config_dir, *data_dir, *state_dir, *cache_dir, *runtime_dir;
@@ -738,7 +738,7 @@ dir_create_home_dir (char *path)
  */
 
 void
-dir_create_home_dirs ()
+dir_create_home_dirs (void)
 {
     int rc;
 
@@ -772,7 +772,7 @@ error:
  */
 
 void
-dir_remove_home_dirs ()
+dir_remove_home_dirs (void)
 {
     dir_rmtree (weechat_config_dir);
     if (strcmp (weechat_config_dir, weechat_data_dir) != 0)
@@ -798,7 +798,7 @@ dir_remove_home_dirs ()
  */
 
 char *
-dir_get_string_home_dirs ()
+dir_get_string_home_dirs (void)
 {
     char *dirs[6];
 
diff --git a/src/core/core-dir.h b/src/core/core-dir.h
index 22f702a6e..170905a96 100644
--- a/src/core/core-dir.h
+++ b/src/core/core-dir.h
@@ -20,14 +20,14 @@
 #ifndef WEECHAT_DIR_H
 #define WEECHAT_DIR_H
 
-extern char *dir_get_temp_dir();
+extern char *dir_get_temp_dir (void);
 extern int dir_mkdir_home (const char *directory, int mode);
 extern int dir_mkdir (const char *directory, int mode);
 extern int dir_mkdir_parents (const char *directory, int mode);
 extern int dir_rmtree (const char *directory);
-extern void dir_create_home_dirs ();
-extern void dir_remove_home_dirs ();
-extern char *dir_get_string_home_dirs ();
+extern void dir_create_home_dirs (void);
+extern void dir_remove_home_dirs (void);
+extern char *dir_get_string_home_dirs (void);
 extern void dir_exec_on_files (const char *directory, int recurse_subdirs,
                                int hidden_files,
                                void (*callback)(void *data,
diff --git a/src/core/core-hdata.c b/src/core/core-hdata.c
index 4168869c7..fd4723bfc 100644
--- a/src/core/core-hdata.c
+++ b/src/core/core-hdata.c
@@ -1467,7 +1467,7 @@ hdata_free_all_plugin (struct t_weechat_plugin *plugin)
  */
 
 void
-hdata_free_all ()
+hdata_free_all (void)
 {
     hashtable_remove_all (weechat_hdata);
 }
@@ -1540,7 +1540,7 @@ hdata_print_log_map_cb (void *data, struct t_hashtable *hashtable,
  */
 
 void
-hdata_print_log ()
+hdata_print_log (void)
 {
     hashtable_map (weechat_hdata, &hdata_print_log_map_cb, NULL);
 }
@@ -1565,7 +1565,7 @@ hdata_free_hdata_cb (struct t_hashtable *hashtable,
  */
 
 void
-hdata_init ()
+hdata_init (void)
 {
     weechat_hdata = hashtable_new (32,
                                    WEECHAT_HASHTABLE_STRING,
@@ -1580,7 +1580,7 @@ hdata_init ()
  */
 
 void
-hdata_end ()
+hdata_end (void)
 {
     hdata_free_all ();
     hashtable_free (weechat_hdata);
diff --git a/src/core/core-hdata.h b/src/core/core-hdata.h
index bf99f3fb5..b546d430b 100644
--- a/src/core/core-hdata.h
+++ b/src/core/core-hdata.h
@@ -151,9 +151,9 @@ extern int hdata_update (struct t_hdata *hdata, void *pointer,
 extern const char *hdata_get_string (struct t_hdata *hdata,
                                      const char *property);
 extern void hdata_free_all_plugin (struct t_weechat_plugin *plugin);
-extern void hdata_free_all ();
-extern void hdata_print_log ();
-extern void hdata_init ();
-extern void hdata_end ();
+extern void hdata_free_all (void);
+extern void hdata_print_log (void);
+extern void hdata_init (void);
+extern void hdata_end (void);
 
 #endif /* WEECHAT_HDATA_H */
diff --git a/src/core/core-hook.c b/src/core/core-hook.c
index 194daca61..96388fa9d 100644
--- a/src/core/core-hook.c
+++ b/src/core/core-hook.c
@@ -159,7 +159,7 @@ t_callback_hook *hook_callback_print_log[HOOK_NUM_TYPES] =
  */
 
 void
-hook_init ()
+hook_init (void)
 {
     int type, sock[2], rc;
 
@@ -367,7 +367,7 @@ hook_remove_from_list (struct t_hook *hook)
  */
 
 void
-hook_remove_deleted ()
+hook_remove_deleted (void)
 {
     int type;
     struct t_hook *ptr_hook, *next_hook;
@@ -458,7 +458,7 @@ hook_valid (struct t_hook *hook)
  */
 
 void
-hook_exec_start ()
+hook_exec_start (void)
 {
     hook_exec_recursion++;
 }
@@ -468,7 +468,7 @@ hook_exec_start ()
  */
 
 void
-hook_exec_end ()
+hook_exec_end (void)
 {
     if (hook_exec_recursion > 0)
         hook_exec_recursion--;
@@ -774,7 +774,7 @@ unhook_all_plugin (struct t_weechat_plugin *plugin, const char *subplugin)
  */
 
 void
-unhook_all ()
+unhook_all (void)
 {
     int type;
     struct t_hook *ptr_hook, *next_hook;
@@ -939,7 +939,7 @@ hook_add_to_infolist (struct t_infolist *infolist, struct t_hook *pointer,
  */
 
 void
-hook_print_log ()
+hook_print_log (void)
 {
     int type;
     struct t_hook *ptr_hook;
diff --git a/src/core/core-hook.h b/src/core/core-hook.h
index 222b2d535..9c2a14700 100644
--- a/src/core/core-hook.h
+++ b/src/core/core-hook.h
@@ -130,15 +130,15 @@ extern long long hook_debug_long_callbacks;
 
 /* hook functions */
 
-extern void hook_init ();
+extern void hook_init (void);
 extern void hook_add_to_list (struct t_hook *new_hook);
 extern void hook_init_data (struct t_hook *hook,
                             struct t_weechat_plugin *plugin,
                             int type, int priority,
                             const void *callback_pointer, void *callback_data);
 extern int hook_valid (struct t_hook *hook);
-extern void hook_exec_start ();
-extern void hook_exec_end ();
+extern void hook_exec_start (void);
+extern void hook_exec_end (void);
 extern void hook_callback_start (struct t_hook *hook,
                                  struct t_hook_exec_cb *hook_exec_cb);
 extern void hook_callback_end (struct t_hook *hook,
@@ -150,10 +150,10 @@ extern void hook_schedule_clean_process (pid_t pid);
 extern void unhook (struct t_hook *hook);
 extern void unhook_all_plugin (struct t_weechat_plugin *plugin,
                                const char *subplugin);
-extern void unhook_all ();
+extern void unhook_all (void);
 extern int hook_add_to_infolist (struct t_infolist *infolist,
                                  struct t_hook *hook,
                                  const char *arguments);
-extern void hook_print_log ();
+extern void hook_print_log (void);
 
 #endif /* WEECHAT_HOOK_H */
diff --git a/src/core/core-infolist.c b/src/core/core-infolist.c
index 81079deec..a34837a8a 100644
--- a/src/core/core-infolist.c
+++ b/src/core/core-infolist.c
@@ -720,7 +720,7 @@ infolist_free_all_plugin (struct t_weechat_plugin *plugin)
  */
 
 void
-infolist_print_log ()
+infolist_print_log (void)
 {
     struct t_infolist *ptr_infolist;
     struct t_infolist_item *ptr_item;
diff --git a/src/core/core-infolist.h b/src/core/core-infolist.h
index 4b5910adb..8f86db4d8 100644
--- a/src/core/core-infolist.h
+++ b/src/core/core-infolist.h
@@ -111,6 +111,6 @@ extern time_t infolist_time (struct t_infolist *infolist,
                              const char *var);
 extern void infolist_free (struct t_infolist *infolist);
 extern void infolist_free_all_plugin (struct t_weechat_plugin *plugin);
-extern void infolist_print_log ();
+extern void infolist_print_log (void);
 
 #endif /* WEECHAT_INFOLIST_H */
diff --git a/src/core/core-list.c b/src/core/core-list.c
index 4125943d3..f9f9c3fe1 100644
--- a/src/core/core-list.c
+++ b/src/core/core-list.c
@@ -40,7 +40,7 @@
  */
 
 struct t_weelist *
-weelist_new ()
+weelist_new (void)
 {
     struct t_weelist *new_weelist;
 
diff --git a/src/core/core-list.h b/src/core/core-list.h
index b8aa456db..2db5bf57e 100644
--- a/src/core/core-list.h
+++ b/src/core/core-list.h
@@ -35,7 +35,7 @@ struct t_weelist
     int size;                          /* number of items in list           */
 };
 
-extern struct t_weelist *weelist_new ();
+extern struct t_weelist *weelist_new (void);
 extern struct t_weelist_item *weelist_add (struct t_weelist *weelist,
                                            const char *data, const char *where,
                                            void *user_data);
diff --git a/src/core/core-log.c b/src/core/core-log.c
index ee9e8cb50..279a4729e 100644
--- a/src/core/core-log.c
+++ b/src/core/core-log.c
@@ -117,7 +117,7 @@ log_open (const char *filename, const char *mode)
  */
 
 void
-log_init ()
+log_init (void)
 {
     if (!log_open (NULL, "w"))
     {
@@ -228,7 +228,7 @@ log_printf_hexa (const char *spaces, const char *string)
  */
 
 void
-log_close ()
+log_close (void)
 {
     /* close log file */
     if (weechat_log_file)
@@ -256,7 +256,7 @@ log_close ()
  */
 
 int
-log_crash_rename ()
+log_crash_rename (void)
 {
     char *old_name, *new_name;
     time_t time_now;
diff --git a/src/core/core-log.h b/src/core/core-log.h
index 2f4379381..c7d127a5a 100644
--- a/src/core/core-log.h
+++ b/src/core/core-log.h
@@ -26,10 +26,10 @@ extern char *weechat_log_filename;
 extern FILE *weechat_log_file;
 extern int weechat_log_use_time;
 
-extern void log_init ();
-extern void log_close ();
+extern void log_init (void);
+extern void log_close (void);
 extern void log_printf (const char *message, ...);
 extern void log_printf_hexa (const char *spaces, const char *string);
-extern int log_crash_rename ();
+extern int log_crash_rename (void);
 
 #endif /* WEECHAT_LOG_H */
diff --git a/src/core/core-network.c b/src/core/core-network.c
index 3e140895c..893f6314a 100644
--- a/src/core/core-network.c
+++ b/src/core/core-network.c
@@ -81,7 +81,7 @@ gnutls_certificate_credentials_t gnutls_xcred; /* GnuTLS client credentials */
  */
 
 void
-network_init_gcrypt ()
+network_init_gcrypt (void)
 {
     if (weechat_no_gcrypt)
         return;
@@ -96,7 +96,7 @@ network_init_gcrypt ()
  */
 
 void
-network_allocate_credentials ()
+network_allocate_credentials (void)
 {
     gnutls_certificate_allocate_credentials (&gnutls_xcred);
     gnutls_certificate_set_verify_function (gnutls_xcred,
@@ -279,7 +279,7 @@ network_reload_ca_files (int force_display)
  */
 
 void
-network_init_gnutls ()
+network_init_gnutls (void)
 {
     if (!weechat_no_gnutls)
     {
@@ -296,7 +296,7 @@ network_init_gnutls ()
  */
 
 void
-network_end ()
+network_end (void)
 {
     if (network_init_gnutls_ok)
     {
diff --git a/src/core/core-network.h b/src/core/core-network.h
index af538ec03..6d18acb2d 100644
--- a/src/core/core-network.h
+++ b/src/core/core-network.h
@@ -48,11 +48,11 @@ extern int network_num_certs_system;
 extern int network_num_certs_user;
 extern int network_num_certs;
 
-extern void network_init_gcrypt ();
+extern void network_init_gcrypt (void);
 extern void network_load_ca_files (int force_display);
 extern void network_reload_ca_files (int force_display);
-extern void network_init_gnutls ();
-extern void network_end ();
+extern void network_init_gnutls (void);
+extern void network_end (void);
 extern int network_pass_proxy (const char *proxy, int sock,
                                const char *address, int port);
 extern int network_connect_to (const char *proxy, struct sockaddr *address,
diff --git a/src/core/core-proxy.c b/src/core/core-proxy.c
index b4e756869..7a362ed1b 100644
--- a/src/core/core-proxy.c
+++ b/src/core/core-proxy.c
@@ -472,7 +472,7 @@ proxy_new (const char *name, const char *type, const char *ipv6,
  */
 
 void
-proxy_use_temp_proxies ()
+proxy_use_temp_proxies (void)
 {
     struct t_proxy *ptr_temp_proxy, *next_temp_proxy;
     int i, num_options_ok;
@@ -566,7 +566,7 @@ proxy_free (struct t_proxy *proxy)
  */
 
 void
-proxy_free_all ()
+proxy_free_all (void)
 {
     while (weechat_proxies)
     {
@@ -647,7 +647,7 @@ proxy_add_to_infolist (struct t_infolist *infolist, struct t_proxy *proxy)
  */
 
 void
-proxy_print_log ()
+proxy_print_log (void)
 {
     struct t_proxy *ptr_proxy;
 
diff --git a/src/core/core-proxy.h b/src/core/core-proxy.h
index 14c3071b9..5bbffb092 100644
--- a/src/core/core-proxy.h
+++ b/src/core/core-proxy.h
@@ -89,14 +89,14 @@ extern struct t_proxy *proxy_new (const char *name,
                                   const char *port,
                                   const char *username,
                                   const char *password);
-extern void proxy_use_temp_proxies ();
+extern void proxy_use_temp_proxies (void);
 extern void proxy_free (struct t_proxy *proxy);
-extern void proxy_free_all ();
+extern void proxy_free_all (void);
 extern struct t_hdata *proxy_hdata_proxy_cb (const void *pointer,
                                              void *data,
                                              const char *hdata_name);
 extern int proxy_add_to_infolist (struct t_infolist *infolist,
                                   struct t_proxy *proxy);
-extern void proxy_print_log ();
+extern void proxy_print_log (void);
 
 #endif /* WEECHAT_PROXY_H */
diff --git a/src/core/core-secure-buffer.c b/src/core/core-secure-buffer.c
index 72d53157b..708e91c4c 100644
--- a/src/core/core-secure-buffer.c
+++ b/src/core/core-secure-buffer.c
@@ -85,7 +85,7 @@ secure_buffer_display_data (void *data,
  */
 
 void
-secure_buffer_display ()
+secure_buffer_display (void)
 {
     int line, count, count_encrypted, hash_algo;
     char str_supported[1024];
@@ -197,7 +197,7 @@ secure_buffer_close_cb (const void *pointer, void *data,
  */
 
 void
-secure_buffer_assign ()
+secure_buffer_assign (void)
 {
     if (!secure_buffer)
     {
@@ -215,7 +215,7 @@ secure_buffer_assign ()
  */
 
 void
-secure_buffer_open ()
+secure_buffer_open (void)
 {
     struct t_hashtable *properties;
 
diff --git a/src/core/core-secure-buffer.h b/src/core/core-secure-buffer.h
index 6ae647700..1c7a659ca 100644
--- a/src/core/core-secure-buffer.h
+++ b/src/core/core-secure-buffer.h
@@ -25,8 +25,8 @@
 extern struct t_gui_buffer *secure_buffer;
 extern int secure_buffer_display_values;
 
-extern void secure_buffer_display ();
-extern void secure_buffer_assign ();
-extern void secure_buffer_open ();
+extern void secure_buffer_display (void);
+extern void secure_buffer_assign (void);
+extern void secure_buffer_open (void);
 
 #endif /* WEECHAT_SECURE_BUFFER_H */
diff --git a/src/core/core-secure-config.c b/src/core/core-secure-config.c
index 9e767cd00..edefd2b2a 100644
--- a/src/core/core-secure-config.c
+++ b/src/core/core-secure-config.c
@@ -542,7 +542,7 @@ secure_config_data_write_cb (const void *pointer, void *data,
  */
 
 int
-secure_config_init_options ()
+secure_config_init_options (void)
 {
     secure_config_file = config_file_new (NULL, SECURE_CONFIG_PRIO_NAME,
                                           &secure_config_reload_cb, NULL, NULL);
@@ -638,7 +638,7 @@ secure_config_init_options ()
  */
 
 int
-secure_config_read ()
+secure_config_read (void)
 {
     int rc;
 
@@ -661,7 +661,7 @@ secure_config_read ()
  */
 
 int
-secure_config_write ()
+secure_config_write (void)
 {
     return config_file_write (secure_config_file);
 }
@@ -675,7 +675,7 @@ secure_config_write ()
  */
 
 int
-secure_config_init ()
+secure_config_init (void)
 {
     int rc;
 
@@ -695,7 +695,7 @@ secure_config_init ()
  */
 
 void
-secure_config_free ()
+secure_config_free (void)
 {
     config_file_free (secure_config_file);
     secure_config_file = NULL;
diff --git a/src/core/core-secure-config.h b/src/core/core-secure-config.h
index 7b9be6342..4777b45a2 100644
--- a/src/core/core-secure-config.h
+++ b/src/core/core-secure-config.h
@@ -31,9 +31,9 @@ extern struct t_config_option *secure_config_crypt_hash_algo;
 extern struct t_config_option *secure_config_crypt_passphrase_command;
 extern struct t_config_option *secure_config_crypt_salt;
 
-extern int secure_config_read ();
-extern int secure_config_write ();
-extern int secure_config_init ();
-extern void secure_config_free ();
+extern int secure_config_read (void);
+extern int secure_config_write (void);
+extern int secure_config_init (void);
+extern void secure_config_free (void);
 
 #endif /* WEECHAT_SECURE_CONFIG_H */
diff --git a/src/core/core-secure.c b/src/core/core-secure.c
index f6a90d573..017852137 100644
--- a/src/core/core-secure.c
+++ b/src/core/core-secure.c
@@ -500,7 +500,7 @@ secure_decrypt_data_not_decrypted (const char *passphrase)
  */
 
 int
-secure_init ()
+secure_init (void)
 {
     char *ptr_phrase;
 
@@ -541,7 +541,7 @@ secure_init ()
  */
 
 void
-secure_end ()
+secure_end (void)
 {
     if (secure_passphrase)
     {
diff --git a/src/core/core-secure.h b/src/core/core-secure.h
index 0a3ed95cd..4a2bb024d 100644
--- a/src/core/core-secure.h
+++ b/src/core/core-secure.h
@@ -43,7 +43,7 @@ extern int secure_decrypt_data (const char *buffer, int length_buffer,
                                 const char *passphrase, char **decrypted,
                                 int *length_decrypted);
 extern int secure_decrypt_data_not_decrypted (const char *passphrase);
-extern int secure_init ();
-extern void secure_end ();
+extern int secure_init (void);
+extern void secure_end (void);
 
 #endif /* WEECHAT_SECURE_H */
diff --git a/src/core/core-signal.c b/src/core/core-signal.c
index 64643ac89..4f2ccf939 100644
--- a/src/core/core-signal.c
+++ b/src/core/core-signal.c
@@ -281,7 +281,7 @@ signal_handle_number (int signal_number, int count, const char *command)
  */
 
 void
-signal_handle ()
+signal_handle (void)
 {
     /* SIGUSR1 */
     signal_handle_number (SIGUSR1, signal_sigusr1_count,
@@ -314,7 +314,7 @@ signal_handle ()
  */
 
 void
-signal_suspend ()
+signal_suspend (void)
 {
     kill (getpid (), SIGTSTP);
     gui_window_ask_refresh (2);
@@ -325,7 +325,7 @@ signal_suspend ()
  */
 
 void
-signal_init ()
+signal_init (void)
 {
     /* ignore some signals */
     signal_catch (SIGINT, SIG_IGN);
diff --git a/src/core/core-signal.h b/src/core/core-signal.h
index e9f7fd0a2..8167f1896 100644
--- a/src/core/core-signal.h
+++ b/src/core/core-signal.h
@@ -31,8 +31,8 @@ extern struct t_signal signal_list[];
 extern int signal_search_number (int signal_number);
 extern int signal_search_name (const char *name);
 extern void signal_catch (int signum, void (*handler)(int));
-extern void signal_handle ();
-extern void signal_suspend ();
-extern void signal_init ();
+extern void signal_handle (void);
+extern void signal_suspend (void);
+extern void signal_init (void);
 
 #endif /* WEECHAT_SIGNAL_H */
diff --git a/src/core/core-string.c b/src/core/core-string.c
index 8e90bf7ec..2d94b8617 100644
--- a/src/core/core-string.c
+++ b/src/core/core-string.c
@@ -4875,7 +4875,7 @@ string_concat (const char *separator, ...)
  */
 
 void
-string_init ()
+string_init (void)
 {
     int i;
 
@@ -4890,7 +4890,7 @@ string_init ()
  */
 
 void
-string_end ()
+string_end (void)
 {
     int i;
 
diff --git a/src/core/core-string.h b/src/core/core-string.h
index 4be42773a..b6992f9cd 100644
--- a/src/core/core-string.h
+++ b/src/core/core-string.h
@@ -166,7 +166,7 @@ extern int string_dyn_copy (char **string, const char *new_string);
 extern int string_dyn_concat (char **string, const char *add, int bytes);
 extern char *string_dyn_free (char **string, int free_string);
 extern const char *string_concat (const char *separator, ...);
-extern void string_init ();
-extern void string_end ();
+extern void string_init (void);
+extern void string_end (void);
 
 #endif /* WEECHAT_STRING_H */
diff --git a/src/core/core-sys.c b/src/core/core-sys.c
index aeee6c548..68eff601f 100644
--- a/src/core/core-sys.c
+++ b/src/core/core-sys.c
@@ -176,7 +176,7 @@ sys_setrlimit_resource (const char *resource_name, long long limit)
  */
 
 void
-sys_setrlimit ()
+sys_setrlimit (void)
 {
 #ifdef HAVE_SYS_RESOURCE_H
     char **items, *pos, *error;
@@ -222,7 +222,7 @@ sys_setrlimit ()
  */
 
 void
-sys_display_rlimit ()
+sys_display_rlimit (void)
 {
 #ifdef HAVE_SYS_RESOURCE_H
     struct rlimit rlim;
@@ -280,7 +280,7 @@ sys_display_rlimit ()
  */
 
 void
-sys_display_rusage ()
+sys_display_rusage (void)
 {
 #ifdef HAVE_SYS_RESOURCE_H
     struct rusage usage;
diff --git a/src/core/core-sys.h b/src/core/core-sys.h
index ffc147a31..c0ab760ca 100644
--- a/src/core/core-sys.h
+++ b/src/core/core-sys.h
@@ -28,9 +28,9 @@ struct t_rlimit_resource
 };
 #endif /* HAVE_SYS_RESOURCE_H */
 
-extern void sys_setrlimit ();
-extern void sys_display_rlimit ();
-extern void sys_display_rusage ();
+extern void sys_setrlimit (void);
+extern void sys_display_rlimit (void);
+extern void sys_display_rusage (void);
 extern void sys_waitpid (int number_processes);
 
 #endif /* WEECHAT_SYS_H */
diff --git a/src/core/core-upgrade.c b/src/core/core-upgrade.c
index 5439a26c2..4077c5ec2 100644
--- a/src/core/core-upgrade.c
+++ b/src/core/core-upgrade.c
@@ -376,7 +376,7 @@ upgrade_weechat_save_layout_window (struct t_upgrade_file *upgrade_file)
  */
 
 int
-upgrade_weechat_save ()
+upgrade_weechat_save (void)
 {
     int rc;
     struct t_upgrade_file *upgrade_file;
@@ -904,7 +904,7 @@ upgrade_weechat_read_cb (const void *pointer, void *data,
  */
 
 int
-upgrade_weechat_load ()
+upgrade_weechat_load (void)
 {
     int rc;
     struct t_upgrade_file *upgrade_file;
@@ -977,7 +977,7 @@ upgrade_weechat_remove_file_cb (void *data, const char *filename)
  */
 
 void
-upgrade_weechat_end ()
+upgrade_weechat_end (void)
 {
     struct timeval tv_now;
     long long time_diff;
diff --git a/src/core/core-upgrade.h b/src/core/core-upgrade.h
index a62070ae1..432aa263a 100644
--- a/src/core/core-upgrade.h
+++ b/src/core/core-upgrade.h
@@ -37,8 +37,8 @@ enum t_upgrade_weechat_type
     UPGRADE_WEECHAT_TYPE_LAYOUT_WINDOW,
 };
 
-int upgrade_weechat_save ();
-int upgrade_weechat_load ();
-void upgrade_weechat_end ();
+int upgrade_weechat_save (void);
+int upgrade_weechat_load (void);
+void upgrade_weechat_end (void);
 
 #endif /* WEECHAT_UPGRADE_H */
diff --git a/src/core/core-url.c b/src/core/core-url.c
index d965bb89c..e17c31146 100644
--- a/src/core/core-url.c
+++ b/src/core/core-url.c
@@ -1293,7 +1293,7 @@ weeurl_option_add_to_infolist (struct t_infolist *infolist,
  */
 
 void
-weeurl_init ()
+weeurl_init (void)
 {
     curl_global_init (CURL_GLOBAL_ALL);
 }
@@ -1303,7 +1303,7 @@ weeurl_init ()
  */
 
 void
-weeurl_end ()
+weeurl_end (void)
 {
     curl_global_cleanup ();
 }
diff --git a/src/core/core-url.h b/src/core/core-url.h
index 86408041c..90cdaa02a 100644
--- a/src/core/core-url.h
+++ b/src/core/core-url.h
@@ -62,7 +62,7 @@ extern int weeurl_download (const char *url, struct t_hashtable *options,
                             struct t_hashtable *output);
 extern int weeurl_option_add_to_infolist (struct t_infolist *infolist,
                                           struct t_url_option *option);
-extern void weeurl_init ();
-extern void weeurl_end ();
+extern void weeurl_init (void);
+extern void weeurl_end (void);
 
 #endif /* WEECHAT_URL_H */
diff --git a/src/core/core-utf8.c b/src/core/core-utf8.c
index d812ff039..1f87e8b44 100644
--- a/src/core/core-utf8.c
+++ b/src/core/core-utf8.c
@@ -46,7 +46,7 @@ int local_utf8 = 0;
  */
 
 void
-utf8_init ()
+utf8_init (void)
 {
     local_utf8 = (string_strcasecmp (weechat_local_charset, "utf-8") == 0);
 }
diff --git a/src/core/core-utf8.h b/src/core/core-utf8.h
index 1029e8a31..77e5bc2c5 100644
--- a/src/core/core-utf8.h
+++ b/src/core/core-utf8.h
@@ -22,7 +22,7 @@
 
 extern int local_utf8;
 
-extern void utf8_init ();
+extern void utf8_init (void);
 extern int utf8_has_8bits (const char *string);
 extern int utf8_is_valid (const char *string, int length, char **error);
 extern void utf8_normalize (char *string, char replacement);
diff --git a/src/core/core-version.c b/src/core/core-version.c
index e6d63a922..41d5b8d4f 100644
--- a/src/core/core-version.c
+++ b/src/core/core-version.c
@@ -32,7 +32,7 @@
  */
 
 const char *
-version_get_name ()
+version_get_name (void)
 {
     return PACKAGE_NAME;
 }
@@ -47,7 +47,7 @@ version_get_name ()
  */
 
 const char *
-version_get_version ()
+version_get_version (void)
 {
     return PACKAGE_VERSION;
 }
@@ -62,7 +62,7 @@ version_get_version ()
  */
 
 const char *
-version_get_name_version ()
+version_get_name_version (void)
 {
     return PACKAGE_STRING;
 }
@@ -76,7 +76,7 @@ version_get_name_version ()
  */
 
 const char *
-version_get_git ()
+version_get_git (void)
 {
     return PACKAGE_VERSION_GIT;
 }
@@ -93,7 +93,7 @@ version_get_git ()
  */
 
 const char *
-version_get_version_with_git ()
+version_get_version_with_git (void)
 {
     const char *git_version;
     static char version[256];
@@ -117,7 +117,7 @@ version_get_version_with_git ()
  */
 
 const char *
-version_get_compilation_date ()
+version_get_compilation_date (void)
 {
     return __DATE__;
 }
@@ -130,7 +130,7 @@ version_get_compilation_date ()
  */
 
 const char *
-version_get_compilation_time ()
+version_get_compilation_time (void)
 {
     return __TIME__;
 }
@@ -143,7 +143,7 @@ version_get_compilation_time ()
  */
 
 const char *
-version_get_compilation_date_time ()
+version_get_compilation_date_time (void)
 {
     return __DATE__ " " __TIME__;
 }
diff --git a/src/core/core-version.h b/src/core/core-version.h
index 774af62d9..94b09f431 100644
--- a/src/core/core-version.h
+++ b/src/core/core-version.h
@@ -20,13 +20,13 @@
 #ifndef WEECHAT_VERSION_H
 #define WEECHAT_VERSION_H
 
-extern const char *version_get_name ();
-extern const char *version_get_version ();
-extern const char *version_get_name_version ();
-extern const char *version_get_git ();
-extern const char *version_get_version_with_git ();
-extern const char *version_get_compilation_date ();
-extern const char *version_get_compilation_time ();
-extern const char *version_get_compilation_date_time ();
+extern const char *version_get_name (void);
+extern const char *version_get_version (void);
+extern const char *version_get_name_version (void);
+extern const char *version_get_git (void);
+extern const char *version_get_version_with_git (void);
+extern const char *version_get_compilation_date (void);
+extern const char *version_get_compilation_time (void);
+extern const char *version_get_compilation_date_time (void);
 
 #endif /* WEECHAT_VERSION_H */
diff --git a/src/core/hook/hook-fd.c b/src/core/hook/hook-fd.c
index a4c6ae361..0264ba45f 100644
--- a/src/core/hook/hook-fd.c
+++ b/src/core/hook/hook-fd.c
@@ -89,7 +89,7 @@ hook_fd_search (int fd)
  */
 
 void
-hook_fd_realloc_pollfd ()
+hook_fd_realloc_pollfd (void)
 {
     struct pollfd *ptr_pollfd;
     int count;
@@ -201,7 +201,7 @@ hook_fd (struct t_weechat_plugin *plugin, int fd, int flag_read,
  */
 
 void
-hook_fd_exec ()
+hook_fd_exec (void)
 {
     struct t_hook *ptr_hook, *next_hook;
     struct t_hook_exec_cb hook_exec_cb;
diff --git a/src/core/hook/hook-fd.h b/src/core/hook/hook-fd.h
index 585bc6e2d..07e29339e 100644
--- a/src/core/hook/hook-fd.h
+++ b/src/core/hook/hook-fd.h
@@ -50,7 +50,7 @@ extern struct t_hook *hook_fd (struct t_weechat_plugin *plugin, int fd,
                                t_hook_callback_fd *callback,
                                const void *callback_pointer,
                                void *callback_data);
-extern void hook_fd_exec ();
+extern void hook_fd_exec (void);
 extern void hook_fd_free_data (struct t_hook *hook);
 extern int hook_fd_add_to_infolist (struct t_infolist_item *item,
                                     struct t_hook *hook);
diff --git a/src/core/hook/hook-process.c b/src/core/hook/hook-process.c
index 7263c1b41..2722c199a 100644
--- a/src/core/hook/hook-process.c
+++ b/src/core/hook/hook-process.c
@@ -787,7 +787,7 @@ error:
  */
 
 void
-hook_process_exec ()
+hook_process_exec (void)
 {
     struct t_hook *ptr_hook, *next_hook;
     struct t_hook_exec_cb hook_exec_cb;
diff --git a/src/core/hook/hook-process.h b/src/core/hook/hook-process.h
index b3599c4bf..be656cb1c 100644
--- a/src/core/hook/hook-process.h
+++ b/src/core/hook/hook-process.h
@@ -70,7 +70,7 @@ extern struct t_hook *hook_process_hashtable (struct t_weechat_plugin *plugin,
                                               t_hook_callback_process *callback,
                                               const void *callback_pointer,
                                               void *callback_data);
-extern void hook_process_exec ();
+extern void hook_process_exec (void);
 extern void hook_process_free_data (struct t_hook *hook);
 extern int hook_process_add_to_infolist (struct t_infolist_item *item,
                                          struct t_hook *hook);
diff --git a/src/core/hook/hook-timer.c b/src/core/hook/hook-timer.c
index 8dafe748d..5b490f070 100644
--- a/src/core/hook/hook-timer.c
+++ b/src/core/hook/hook-timer.c
@@ -182,7 +182,7 @@ hook_timer (struct t_weechat_plugin *plugin, long interval, int align_second,
  */
 
 void
-hook_timer_check_system_clock ()
+hook_timer_check_system_clock (void)
 {
     time_t now;
     long diff_time;
@@ -222,7 +222,7 @@ hook_timer_check_system_clock ()
  */
 
 int
-hook_timer_get_time_to_next ()
+hook_timer_get_time_to_next (void)
 {
     struct t_hook *ptr_hook;
     int found, timeout;
@@ -300,7 +300,7 @@ end:
  */
 
 void
-hook_timer_exec ()
+hook_timer_exec (void)
 {
     struct t_hook *ptr_hook, *next_hook;
     struct t_hook_exec_cb hook_exec_cb;
diff --git a/src/core/hook/hook-timer.h b/src/core/hook/hook-timer.h
index 9b56bc825..6b6050c52 100644
--- a/src/core/hook/hook-timer.h
+++ b/src/core/hook/hook-timer.h
@@ -51,8 +51,8 @@ extern struct t_hook *hook_timer (struct t_weechat_plugin *plugin,
                                   t_hook_callback_timer *callback,
                                   const void *callback_pointer,
                                   void *callback_data);
-extern int hook_timer_get_time_to_next ();
-extern void hook_timer_exec ();
+extern int hook_timer_get_time_to_next (void);
+extern void hook_timer_exec (void);
 extern void hook_timer_free_data (struct t_hook *hook);
 extern int hook_timer_add_to_infolist (struct t_infolist_item *item,
                                        struct t_hook *hook);
diff --git a/src/core/weechat.c b/src/core/weechat.c
index 5862e5b7b..187c73961 100644
--- a/src/core/weechat.c
+++ b/src/core/weechat.c
@@ -142,7 +142,7 @@ int weechat_auto_load_scripts = 1;     /* auto-load scripts                 */
  */
 
 void
-weechat_display_copyright ()
+weechat_display_copyright (void)
 {
     string_fprintf (stdout, "\n");
     string_fprintf (
@@ -164,7 +164,7 @@ weechat_display_copyright ()
  */
 
 void
-weechat_display_usage ()
+weechat_display_usage (void)
 {
     weechat_display_copyright ();
     string_fprintf (stdout, "\n");
@@ -410,7 +410,7 @@ weechat_parse_args (int argc, char *argv[])
  */
 
 void
-weechat_startup_message ()
+weechat_startup_message (void)
 {
     if (weechat_headless)
     {
@@ -485,7 +485,7 @@ weechat_startup_message ()
  */
 
 void
-weechat_term_check ()
+weechat_term_check (void)
 {
     char *term, *sty, *tmux;
     const char *screen_terms = "screen-256color, screen";
@@ -553,7 +553,7 @@ weechat_term_check ()
  */
 
 void
-weechat_locale_check ()
+weechat_locale_check (void)
 {
     if (!weechat_locale_ok)
     {
@@ -609,7 +609,7 @@ weechat_shutdown (int return_code, int crash)
  */
 
 void
-weechat_init_gettext ()
+weechat_init_gettext (void)
 {
     weechat_locale_ok = (setlocale (LC_ALL, "") != NULL);   /* init gettext */
 #if ENABLE_NLS == 1
@@ -631,7 +631,7 @@ weechat_init_gettext ()
  */
 
 void
-weechat_init (int argc, char *argv[], void (*gui_init_cb)())
+weechat_init (int argc, char *argv[], void (*gui_init_cb)(void))
 {
     weechat_first_start_time = time (NULL); /* initialize start time        */
     gettimeofday (&weechat_current_start_timeval, NULL);
diff --git a/src/core/weechat.h b/src/core/weechat.h
index 206d9cc49..fcbc6d943 100644
--- a/src/core/weechat.h
+++ b/src/core/weechat.h
@@ -127,10 +127,10 @@ extern struct t_weelist *weechat_startup_commands;
 extern int weechat_auto_connect;
 extern int weechat_auto_load_scripts;
 
-extern void weechat_term_check ();
+extern void weechat_term_check (void);
 extern void weechat_shutdown (int return_code, int crash);
-extern void weechat_init_gettext ();
-extern void weechat_init (int argc, char *argv[], void (*gui_init_cb)());
+extern void weechat_init_gettext (void);
+extern void weechat_init (int argc, char *argv[], void (*gui_init_cb)(void));
 extern void weechat_end (void (*gui_end_cb)(int clean_exit));
 
 #endif /* WEECHAT_H */
diff --git a/src/gui/curses/gui-curses-color.c b/src/gui/curses/gui-curses-color.c
index 3e0a69bc8..19ef7bbcf 100644
--- a/src/gui/curses/gui-curses-color.c
+++ b/src/gui/curses/gui-curses-color.c
@@ -325,7 +325,7 @@ gui_color_assign_by_diff (int *color, const char *color_name, int diff)
  */
 
 int
-gui_color_get_weechat_colors_number ()
+gui_color_get_weechat_colors_number (void)
 {
     return GUI_CURSES_NUM_WEECHAT_COLORS;
 }
@@ -335,7 +335,7 @@ gui_color_get_weechat_colors_number ()
  */
 
 int
-gui_color_get_term_colors ()
+gui_color_get_term_colors (void)
 {
     return gui_color_term_colors;
 }
@@ -345,7 +345,7 @@ gui_color_get_term_colors ()
  */
 
 int
-gui_color_get_term_color_pairs ()
+gui_color_get_term_color_pairs (void)
 {
     return gui_color_term_color_pairs;
 }
@@ -645,7 +645,7 @@ gui_color_build (int number, int foreground, int background)
  */
 
 void
-gui_color_init_vars ()
+gui_color_init_vars (void)
 {
     gui_color_term_has_colors = (has_colors ()) ? 1 : 0;
     gui_color_term_colors = 0;
@@ -705,7 +705,7 @@ gui_color_init_vars ()
  */
 
 void
-gui_color_free_vars ()
+gui_color_free_vars (void)
 {
     if (gui_color_pairs)
     {
@@ -724,7 +724,7 @@ gui_color_free_vars ()
  */
 
 void
-gui_color_init_pairs_terminal ()
+gui_color_init_pairs_terminal (void)
 {
     int i;
 
@@ -745,7 +745,7 @@ gui_color_init_pairs_terminal ()
  */
 
 void
-gui_color_init_pairs_weechat ()
+gui_color_init_pairs_weechat (void)
 {
     int i;
     short *foregrounds, *backgrounds;
@@ -775,7 +775,7 @@ gui_color_init_pairs_weechat ()
  */
 
 void
-gui_color_display_terminal_colors ()
+gui_color_display_terminal_colors (void)
 {
     int lines, columns, line, col, color;
     char str_line[1024], str_color[64];
@@ -833,7 +833,7 @@ gui_color_display_terminal_colors ()
  */
 
 void
-gui_color_buffer_display_timer ()
+gui_color_buffer_display_timer (void)
 {
     if (gui_color_buffer && gui_color_use_term_colors)
     {
@@ -866,7 +866,7 @@ gui_color_info_term_colors (char *buffer, int size)
  */
 
 void
-gui_color_buffer_display ()
+gui_color_buffer_display (void)
 {
     int y, i, lines, columns, line, col, color, max_color;
     char str_line[1024], str_color[64], str_rgb[64];
@@ -1170,7 +1170,7 @@ gui_color_timer_cb (const void *pointer, void *data, int remaining_calls)
  */
 
 void
-gui_color_switch_colors ()
+gui_color_switch_colors (void)
 {
     if (gui_color_hook_timer)
     {
@@ -1219,7 +1219,7 @@ gui_color_switch_colors ()
  */
 
 void
-gui_color_reset_pairs ()
+gui_color_reset_pairs (void)
 {
     if (gui_color_pairs)
     {
@@ -1291,7 +1291,7 @@ gui_color_buffer_close_cb (const void *pointer, void *data,
  */
 
 void
-gui_color_buffer_assign ()
+gui_color_buffer_assign (void)
 {
     if (!gui_color_buffer)
     {
@@ -1309,7 +1309,7 @@ gui_color_buffer_assign ()
  */
 
 void
-gui_color_buffer_open ()
+gui_color_buffer_open (void)
 {
     struct t_hashtable *properties;
 
@@ -1383,7 +1383,7 @@ gui_color_palette_add_alias_cb (void *data,
  */
 
 void
-gui_color_palette_build_aliases ()
+gui_color_palette_build_aliases (void)
 {
     int i;
     struct t_gui_color_palette *color_palette;
@@ -1540,7 +1540,7 @@ gui_color_palette_free (struct t_gui_color_palette *color_palette)
  */
 
 void
-gui_color_init_weechat ()
+gui_color_init_weechat (void)
 {
     if (CONFIG_BOOLEAN(config_look_color_basic_force_bold)
         || (gui_color_term_colors < 16))
@@ -1614,7 +1614,7 @@ gui_color_init_weechat ()
  */
 
 void
-gui_color_alloc ()
+gui_color_alloc (void)
 {
     if (has_colors ())
     {
@@ -1632,7 +1632,7 @@ gui_color_alloc ()
  */
 
 void
-gui_color_dump ()
+gui_color_dump (void)
 {
     char str_line[1024];
     int fg, bg, index;
diff --git a/src/gui/curses/gui-curses-color.h b/src/gui/curses/gui-curses-color.h
index b59661a1a..634c7a69e 100644
--- a/src/gui/curses/gui-curses-color.h
+++ b/src/gui/curses/gui-curses-color.h
@@ -39,6 +39,6 @@ extern int gui_color_buffer_refresh_needed;
 extern int gui_color_get_gui_attrs (int color);
 extern int gui_color_get_pair (int fg, int bg);
 extern int gui_color_weechat_get_pair (int weechat_color);
-extern void gui_color_alloc ();
+extern void gui_color_alloc (void);
 
 #endif /* WEECHAT_GUI_CURSES_COLOR_H */
diff --git a/src/gui/curses/gui-curses-main.c b/src/gui/curses/gui-curses-main.c
index 5038fb8fb..9f3e76bec 100644
--- a/src/gui/curses/gui-curses-main.c
+++ b/src/gui/curses/gui-curses-main.c
@@ -163,7 +163,7 @@ gui_main_signal_sigint (int signo)
  */
 
 void
-gui_main_init ()
+gui_main_init (void)
 {
     struct t_gui_buffer *ptr_buffer;
     char title[256];
@@ -269,7 +269,7 @@ gui_main_signal_sigwinch (int signo)
  */
 
 void
-gui_main_debug_libs ()
+gui_main_debug_libs (void)
 {
 #if defined(NCURSES_VERSION) && defined(NCURSES_VERSION_PATCH)
     gui_chat_printf (NULL, "    ncurses: %s (patch %d)",
@@ -284,7 +284,7 @@ gui_main_debug_libs ()
  */
 
 void
-gui_main_refreshes ()
+gui_main_refreshes (void)
 {
     struct t_gui_window *ptr_win;
     struct t_gui_buffer *ptr_buffer;
@@ -391,7 +391,7 @@ gui_main_refreshes ()
  */
 
 void
-gui_main_loop ()
+gui_main_loop (void)
 {
     struct t_hook *hook_fd_keyboard;
     int send_signal_sigwinch;
diff --git a/src/gui/curses/gui-curses-main.h b/src/gui/curses/gui-curses-main.h
index 82211a8e4..b50a4b68b 100644
--- a/src/gui/curses/gui-curses-main.h
+++ b/src/gui/curses/gui-curses-main.h
@@ -22,7 +22,7 @@
 
 extern int gui_term_cols, gui_term_lines;
 
-extern void gui_main_init ();
-extern void gui_main_loop ();
+extern void gui_main_init (void);
+extern void gui_main_loop (void);
 
 #endif /* WEECHAT_GUI_CURSES_MAIN_H */
diff --git a/src/gui/curses/gui-curses-mouse.c b/src/gui/curses/gui-curses-mouse.c
index 20c21f035..29af23731 100644
--- a/src/gui/curses/gui-curses-mouse.c
+++ b/src/gui/curses/gui-curses-mouse.c
@@ -86,7 +86,7 @@ char *gui_mouse_button_utf8_codes[][2] =
  */
 
 void
-gui_mouse_enable ()
+gui_mouse_enable (void)
 {
     gui_mouse_enabled = 1;
     fprintf (stderr, "\033[?1005h\033[?1006h\033[?1000h\033[?1002h");
@@ -101,7 +101,7 @@ gui_mouse_enable ()
  */
 
 void
-gui_mouse_disable ()
+gui_mouse_disable (void)
 {
     gui_mouse_enabled = 0;
     fprintf (stderr, "\033[?1002l\033[?1000l\033[?1006l\033[?1005l");
@@ -116,7 +116,7 @@ gui_mouse_disable ()
  */
 
 void
-gui_mouse_display_state ()
+gui_mouse_display_state (void)
 {
     gui_chat_printf (NULL,
                      gui_mouse_enabled ?
@@ -143,7 +143,7 @@ gui_mouse_grab_init (int area)
  */
 
 const char *
-gui_mouse_grab_event2input ()
+gui_mouse_grab_event2input (void)
 {
     struct t_gui_focus_info *focus_info;
     static char area[256];
diff --git a/src/gui/curses/gui-curses-window.c b/src/gui/curses/gui-curses-window.c
index 93a30e456..fd8aa017a 100644
--- a/src/gui/curses/gui-curses-window.c
+++ b/src/gui/curses/gui-curses-window.c
@@ -78,7 +78,7 @@ int gui_window_saved_style_index = 0;  /* index in list of savec styles     */
  */
 
 int
-gui_window_get_width ()
+gui_window_get_width (void)
 {
     return gui_term_cols;
 }
@@ -88,7 +88,7 @@ gui_window_get_width ()
  */
 
 int
-gui_window_get_height ()
+gui_window_get_height (void)
 {
     return gui_term_lines;
 }
@@ -98,7 +98,7 @@ gui_window_get_height ()
  */
 
 void
-gui_window_read_terminal_size ()
+gui_window_read_terminal_size (void)
 {
     struct winsize size;
     int new_width, new_height;
@@ -572,7 +572,7 @@ gui_window_set_custom_color_pair (WINDOW *window, int pair)
  */
 
 void
-gui_window_toggle_emphasis ()
+gui_window_toggle_emphasis (void)
 {
     gui_window_current_emphasis ^= 1;
 }
@@ -1808,7 +1808,7 @@ gui_window_auto_resize (struct t_gui_window_tree *tree,
  */
 
 void
-gui_window_refresh_windows ()
+gui_window_refresh_windows (void)
 {
     struct t_gui_window *ptr_win, *old_current_window;
     struct t_gui_bar_window *ptr_bar_win;
@@ -2685,7 +2685,7 @@ gui_window_set_bracketed_paste_mode (int enable)
  */
 
 void
-gui_window_move_cursor ()
+gui_window_move_cursor (void)
 {
     if (gui_cursor_mode)
     {
@@ -2699,7 +2699,7 @@ gui_window_move_cursor ()
  */
 
 void
-gui_window_term_display_infos ()
+gui_window_term_display_infos (void)
 {
     gui_chat_printf (NULL, "");
     gui_chat_printf (NULL, _("Terminal infos:"));
diff --git a/src/gui/curses/gui-curses-window.h b/src/gui/curses/gui-curses-window.h
index 1d92c6076..827018f8e 100644
--- a/src/gui/curses/gui-curses-window.h
+++ b/src/gui/curses/gui-curses-window.h
@@ -43,7 +43,7 @@ struct t_gui_window_curses_objects
 extern int gui_window_current_color_attr;
 extern int gui_window_current_emphasis;
 
-extern void gui_window_read_terminal_size ();
+extern void gui_window_read_terminal_size (void);
 extern void gui_window_clear (WINDOW *window, int fg, int bg);
 extern void gui_window_clrtoeol (WINDOW *window);
 extern void gui_window_save_style (WINDOW *window);
@@ -59,7 +59,7 @@ extern void gui_window_set_custom_color_fg_bg (WINDOW *window, int fg, int bg,
 extern void gui_window_set_custom_color_pair (WINDOW *window, int pair);
 extern void gui_window_set_custom_color_fg (WINDOW *window, int fg);
 extern void gui_window_set_custom_color_bg (WINDOW *window, int bg);
-extern void gui_window_toggle_emphasis ();
+extern void gui_window_toggle_emphasis (void);
 extern void gui_window_emphasize (WINDOW *window, int x, int y, int count);
 extern void gui_window_string_apply_color_fg (unsigned char **str,
                                               WINDOW *window);
diff --git a/src/gui/curses/headless/main.c b/src/gui/curses/headless/main.c
index 82bdd690d..594ad78d0 100644
--- a/src/gui/curses/headless/main.c
+++ b/src/gui/curses/headless/main.c
@@ -42,7 +42,7 @@
  */
 
 void
-daemonize ()
+daemonize (void)
 {
     pid_t pid;
     int fd, i;
diff --git a/src/gui/curses/headless/ncurses-fake.c b/src/gui/curses/headless/ncurses-fake.c
index c10ab337b..c9a38e36c 100644
--- a/src/gui/curses/headless/ncurses-fake.c
+++ b/src/gui/curses/headless/ncurses-fake.c
@@ -29,13 +29,13 @@ chtype acs_map[256];
 
 
 WINDOW *
-initscr ()
+initscr (void)
 {
     return stdscr;
 }
 
 int
-endwin ()
+endwin (void)
 {
     return OK;
 }
@@ -187,7 +187,7 @@ wclrtobot (WINDOW *win)
 }
 
 int
-refresh ()
+refresh (void)
 {
     return OK;
 }
@@ -238,31 +238,31 @@ init_pair (short pair, short f, short b)
 }
 
 bool
-has_colors ()
+has_colors (void)
 {
     return TRUE;
 }
 
 int
-cbreak ()
+cbreak (void)
 {
     return OK;
 }
 
 int
-start_color ()
+start_color (void)
 {
     return OK;
 }
 
 int
-noecho ()
+noecho (void)
 {
     return OK;
 }
 
 int
-clear ()
+clear (void)
 {
     return OK;
 }
@@ -276,7 +276,7 @@ wclear (WINDOW *win)
 }
 
 bool
-can_change_color ()
+can_change_color (void)
 {
     /* not supported in WeeChat anyway */
     return FALSE;
@@ -402,7 +402,7 @@ mvwvline (WINDOW *win, int y, int x, chtype ch, int n)
 }
 
 int
-raw ()
+raw (void)
 {
     return OK;
 }
@@ -418,12 +418,12 @@ wcolor_set (WINDOW *win, short pair, void *opts)
 }
 
 void
-cur_term ()
+cur_term (void)
 {
 }
 
 int
-use_default_colors ()
+use_default_colors (void)
 {
     return OK;
 }
@@ -438,7 +438,7 @@ resizeterm (int lines, int columns)
 }
 
 int
-getch ()
+getch (void)
 {
     return ERR;
 }
diff --git a/src/gui/curses/headless/ncurses-fake.h b/src/gui/curses/headless/ncurses-fake.h
index a7740f3e7..6f1e9d580 100644
--- a/src/gui/curses/headless/ncurses-fake.h
+++ b/src/gui/curses/headless/ncurses-fake.h
@@ -83,8 +83,8 @@ typedef struct _cchar_t cchar_t;
 extern WINDOW *stdscr;
 extern chtype acs_map[];
 
-extern WINDOW *initscr ();
-extern int endwin ();
+extern WINDOW *initscr (void);
+extern int endwin (void);
 extern WINDOW *newwin (int nlines, int ncols, int begin_y, int begin_x);
 extern int delwin (WINDOW *win);
 extern int move (int y, int x);
@@ -100,19 +100,19 @@ extern int waddnstr (WINDOW *win, const char *str, int n);
 extern int mvaddstr (int y, int x, const char *str);
 extern int mvwaddstr (WINDOW *win, int y, int x, const char *str);
 extern int wclrtobot (WINDOW *win);
-extern int refresh ();
+extern int refresh (void);
 extern int wrefresh (WINDOW *win);
 extern int wnoutrefresh (WINDOW *win);
 extern int wclrtoeol (WINDOW *win);
 extern int mvwprintw (WINDOW *win, int y, int x, const char *fmt, ...);
 extern int init_pair (short pair, short f, short b);
-extern bool has_colors ();
-extern int cbreak ();
-extern int start_color ();
-extern int noecho ();
-extern int clear ();
+extern bool has_colors (void);
+extern int cbreak (void);
+extern int start_color (void);
+extern int noecho (void);
+extern int clear (void);
 extern int wclear (WINDOW *win);
-extern bool can_change_color ();
+extern bool can_change_color (void);
 extern int curs_set (int visibility);
 extern int nodelay (WINDOW *win, bool bf);
 extern int werase (WINDOW *win);
@@ -127,12 +127,12 @@ extern void whline (WINDOW *win, chtype ch, int n);
 extern void wvline (WINDOW *win, chtype ch, int n);
 extern int mvwhline (WINDOW *win, int y, int x, chtype ch, int n);
 extern int mvwvline (WINDOW *win, int y, int x, chtype ch, int n);
-extern int raw ();
+extern int raw (void);
 extern int wcolor_set (WINDOW *win, short pair, void *opts);
-extern void cur_term ();
-extern int use_default_colors ();
+extern void cur_term (void);
+extern int use_default_colors (void);
 extern int resizeterm (int lines, int columns);
-extern int getch ();
+extern int getch (void);
 extern int wgetch (WINDOW *win);
 
 #endif /* WEECHAT_NCURSES_FAKE_H */
diff --git a/src/gui/gui-bar-item-custom.c b/src/gui/gui-bar-item-custom.c
index cc6459673..d1fa05c65 100644
--- a/src/gui/gui-bar-item-custom.c
+++ b/src/gui/gui-bar-item-custom.c
@@ -488,7 +488,7 @@ error:
  */
 
 void
-gui_bar_item_custom_use_temp_items ()
+gui_bar_item_custom_use_temp_items (void)
 {
     struct t_gui_bar_item_custom *ptr_temp_item, *ptr_next_temp_item;
     int i;
@@ -653,7 +653,7 @@ gui_bar_item_custom_free (struct t_gui_bar_item_custom *item)
  */
 
 void
-gui_bar_item_custom_free_all ()
+gui_bar_item_custom_free_all (void)
 {
     while (gui_custom_bar_items)
     {
diff --git a/src/gui/gui-bar-item-custom.h b/src/gui/gui-bar-item-custom.h
index 2a083aa9d..4e505ac6b 100644
--- a/src/gui/gui-bar-item-custom.h
+++ b/src/gui/gui-bar-item-custom.h
@@ -66,11 +66,11 @@ extern struct t_gui_bar_item_custom *gui_bar_item_custom_alloc (const char *name
 extern struct t_gui_bar_item_custom *gui_bar_item_custom_new (const char *name,
                                                               const char *conditions,
                                                               const char *content);
-extern void gui_bar_item_custom_use_temp_items ();
+extern void gui_bar_item_custom_use_temp_items (void);
 extern int gui_bar_item_custom_rename (struct t_gui_bar_item_custom *item,
                                        const char *new_name);
 extern void gui_bar_item_custom_free_data (struct t_gui_bar_item_custom *item);
 extern void gui_bar_item_custom_free (struct t_gui_bar_item_custom *item);
-extern void gui_bar_item_custom_free_all ();
+extern void gui_bar_item_custom_free_all (void);
 
 #endif /* WEECHAT_GUI_BAR_ITEM_CUSTOM_H */
diff --git a/src/gui/gui-bar-item.c b/src/gui/gui-bar-item.c
index 08f38ecdb..fecbb3fda 100644
--- a/src/gui/gui-bar-item.c
+++ b/src/gui/gui-bar-item.c
@@ -739,7 +739,7 @@ gui_bar_item_free (struct t_gui_bar_item *item)
  */
 
 void
-gui_bar_item_free_all ()
+gui_bar_item_free_all (void)
 {
     while (gui_bar_items)
     {
@@ -2341,7 +2341,7 @@ gui_bar_item_hook_signal (const char *signal, const char *item)
  */
 
 void
-gui_bar_item_init ()
+gui_bar_item_init (void)
 {
     char name[128];
 
@@ -2553,7 +2553,7 @@ gui_bar_item_init ()
  */
 
 void
-gui_bar_item_end ()
+gui_bar_item_end (void)
 {
     struct t_gui_bar_item_hook *next_bar_item_hook;
 
@@ -2643,7 +2643,7 @@ gui_bar_item_add_to_infolist (struct t_infolist *infolist,
  */
 
 void
-gui_bar_item_print_log ()
+gui_bar_item_print_log (void)
 {
     struct t_gui_bar_item *ptr_item;
 
diff --git a/src/gui/gui-bar-item.h b/src/gui/gui-bar-item.h
index bcb4fa040..a1c00268d 100644
--- a/src/gui/gui-bar-item.h
+++ b/src/gui/gui-bar-item.h
@@ -117,15 +117,15 @@ extern struct t_gui_bar_item *gui_bar_item_new (struct t_weechat_plugin *plugin,
                                                 void *build_callback_data);
 extern void gui_bar_item_update (const char *name);
 extern void gui_bar_item_free (struct t_gui_bar_item *item);
-extern void gui_bar_item_free_all ();
+extern void gui_bar_item_free_all (void);
 extern void gui_bar_item_free_all_plugin (struct t_weechat_plugin *plugin);
-extern void gui_bar_item_init ();
-extern void gui_bar_item_end ();
+extern void gui_bar_item_init (void);
+extern void gui_bar_item_end (void);
 extern struct t_hdata *gui_bar_item_hdata_bar_item_cb (const void *pointer,
                                                        void *data,
                                                        const char *hdata_name);
 extern int gui_bar_item_add_to_infolist (struct t_infolist *infolist,
                                          struct t_gui_bar_item *bar_item);
-extern void gui_bar_item_print_log ();
+extern void gui_bar_item_print_log (void);
 
 #endif /* WEECHAT_GUI_BAR_ITEM_H */
diff --git a/src/gui/gui-bar.c b/src/gui/gui-bar.c
index 7365968c6..2270d0e08 100644
--- a/src/gui/gui-bar.c
+++ b/src/gui/gui-bar.c
@@ -1835,7 +1835,7 @@ gui_bar_new_default (enum t_gui_bar_default bar)
  */
 
 void
-gui_bar_use_temp_bars ()
+gui_bar_use_temp_bars (void)
 {
     struct t_gui_bar *ptr_temp_bar, *next_temp_bar;
     int i, num_options_ok;
@@ -1908,7 +1908,7 @@ gui_bar_use_temp_bars ()
  */
 
 void
-gui_bar_create_default_input ()
+gui_bar_create_default_input (void)
 {
     struct t_gui_bar *ptr_bar;
     char *buf;
@@ -1952,7 +1952,7 @@ gui_bar_create_default_input ()
  */
 
 void
-gui_bar_create_default_title ()
+gui_bar_create_default_title (void)
 {
     struct t_gui_bar *ptr_bar;
 
@@ -1974,7 +1974,7 @@ gui_bar_create_default_title ()
  */
 
 void
-gui_bar_create_default_status ()
+gui_bar_create_default_status (void)
 {
     struct t_gui_bar *ptr_bar;
 
@@ -1996,7 +1996,7 @@ gui_bar_create_default_status ()
  */
 
 void
-gui_bar_create_default_nicklist ()
+gui_bar_create_default_nicklist (void)
 {
     struct t_gui_bar *ptr_bar;
 
@@ -2018,7 +2018,7 @@ gui_bar_create_default_nicklist ()
  */
 
 void
-gui_bar_create_default ()
+gui_bar_create_default (void)
 {
     gui_bar_create_default_input ();
     gui_bar_create_default_title ();
@@ -2213,7 +2213,7 @@ gui_bar_free (struct t_gui_bar *bar)
  */
 
 void
-gui_bar_free_all ()
+gui_bar_free_all (void)
 {
     while (gui_bars)
     {
@@ -2383,7 +2383,7 @@ gui_bar_add_to_infolist (struct t_infolist *infolist,
  */
 
 void
-gui_bar_print_log ()
+gui_bar_print_log (void)
 {
     struct t_gui_bar *ptr_bar;
     int i, j;
diff --git a/src/gui/gui-bar.h b/src/gui/gui-bar.h
index e92ebf9c7..ae5b62f87 100644
--- a/src/gui/gui-bar.h
+++ b/src/gui/gui-bar.h
@@ -153,22 +153,22 @@ extern struct t_gui_bar *gui_bar_new (const char *name,
                                       const char *color_bg_inactive,
                                       const char *separator,
                                       const char *items);
-extern void gui_bar_use_temp_bars ();
-extern void gui_bar_create_default_input ();
-extern void gui_bar_create_default_title ();
-extern void gui_bar_create_default_status ();
-extern void gui_bar_create_default_nicklist ();
-extern void gui_bar_create_default ();
+extern void gui_bar_use_temp_bars (void);
+extern void gui_bar_create_default_input (void);
+extern void gui_bar_create_default_title (void);
+extern void gui_bar_create_default_status (void);
+extern void gui_bar_create_default_nicklist (void);
+extern void gui_bar_create_default (void);
 extern void gui_bar_update (const char *name);
 extern int gui_bar_scroll (struct t_gui_bar *bar, struct t_gui_window *window,
                            const char *scroll);
 extern void gui_bar_free (struct t_gui_bar *bar);
-extern void gui_bar_free_all ();
+extern void gui_bar_free_all (void);
 extern struct t_hdata *gui_bar_hdata_bar_cb (const void *pointer,
                                              void *data,
                                              const char *hdata_name);
 extern int gui_bar_add_to_infolist (struct t_infolist *infolist,
                                     struct t_gui_bar *bar);
-extern void gui_bar_print_log ();
+extern void gui_bar_print_log (void);
 
 #endif /* WEECHAT_GUI_BAR_H */
diff --git a/src/gui/gui-buffer.c b/src/gui/gui-buffer.c
index 8575bc24e..62cb6317c 100644
--- a/src/gui/gui-buffer.c
+++ b/src/gui/gui-buffer.c
@@ -387,7 +387,7 @@ gui_buffer_notify_set (struct t_gui_buffer *buffer)
  */
 
 void
-gui_buffer_notify_set_all ()
+gui_buffer_notify_set_all (void)
 {
     struct t_gui_buffer *ptr_buffer;
 
@@ -617,7 +617,7 @@ gui_buffer_insert (struct t_gui_buffer *buffer)
  */
 
 long long
-gui_buffer_generate_id ()
+gui_buffer_generate_id (void)
 {
     struct timeval tv;
     long long id;
@@ -1181,7 +1181,7 @@ gui_buffer_new_user (const char *name, enum t_gui_buffer_type buffer_type)
  */
 
 void
-gui_buffer_user_set_callbacks ()
+gui_buffer_user_set_callbacks (void)
 {
     struct t_gui_buffer *ptr_buffer;
     const char *ptr_type;
@@ -2907,7 +2907,7 @@ gui_buffer_set_pointer (struct t_gui_buffer *buffer, const char *property,
  */
 
 void
-gui_buffer_compute_num_displayed ()
+gui_buffer_compute_num_displayed (void)
 {
     struct t_gui_buffer *ptr_buffer;
     struct t_gui_window *ptr_window;
@@ -2988,7 +2988,7 @@ gui_buffer_is_main (const char *plugin_name, const char *name)
  */
 
 struct t_gui_buffer *
-gui_buffer_search_main ()
+gui_buffer_search_main (void)
 {
     struct t_gui_buffer *ptr_buffer;
 
@@ -3411,7 +3411,7 @@ gui_buffer_clear (struct t_gui_buffer *buffer)
  */
 
 void
-gui_buffer_clear_all ()
+gui_buffer_clear_all (void)
 {
     struct t_gui_buffer *ptr_buffer;
 
@@ -3517,7 +3517,7 @@ gui_buffer_get_previous_active_buffer (struct t_gui_buffer *buffer,
  */
 
 int
-gui_buffer_visited_get_index_previous ()
+gui_buffer_visited_get_index_previous (void)
 {
     if ((gui_buffers_visited_count < 2) || (gui_buffers_visited_index == 0))
         return -1;
@@ -3535,7 +3535,7 @@ gui_buffer_visited_get_index_previous ()
  */
 
 int
-gui_buffer_visited_get_index_next ()
+gui_buffer_visited_get_index_next (void)
 {
     if ((gui_buffers_visited_count < 2)
         || (gui_buffers_visited_index < 0)
@@ -3645,7 +3645,7 @@ gui_buffer_visited_remove_by_buffer (struct t_gui_buffer *buffer)
  */
 
 void
-gui_buffer_visited_remove_all ()
+gui_buffer_visited_remove_all (void)
 {
     while (gui_buffers_visited)
     {
@@ -4716,7 +4716,7 @@ gui_buffer_unmerge (struct t_gui_buffer *buffer, int number)
  */
 
 void
-gui_buffer_unmerge_all ()
+gui_buffer_unmerge_all (void)
 {
     struct t_gui_buffer *ptr_buffer, *ptr_next_buffer;
     int number;
@@ -4761,7 +4761,7 @@ gui_buffer_hide (struct t_gui_buffer *buffer)
  */
 
 void
-gui_buffer_hide_all ()
+gui_buffer_hide_all (void)
 {
     struct t_gui_buffer *ptr_buffer;
 
@@ -4794,7 +4794,7 @@ gui_buffer_unhide (struct t_gui_buffer *buffer)
  */
 
 void
-gui_buffer_unhide_all ()
+gui_buffer_unhide_all (void)
 {
     struct t_gui_buffer *ptr_buffer;
 
@@ -4810,7 +4810,7 @@ gui_buffer_unhide_all ()
  */
 
 void
-gui_buffer_sort_by_layout_number ()
+gui_buffer_sort_by_layout_number (void)
 {
     struct t_gui_buffer *ptr_buffer, *ptr_next_buffer;
     struct t_gui_buffer *extra_buffers, *last_extra_buffer;
@@ -5720,7 +5720,7 @@ gui_buffer_dump_hexa (struct t_gui_buffer *buffer)
  */
 
 void
-gui_buffer_print_log ()
+gui_buffer_print_log (void)
 {
     struct t_gui_buffer *ptr_buffer;
     struct t_gui_line *ptr_line;
diff --git a/src/gui/gui-buffer.h b/src/gui/gui-buffer.h
index e9e95a4a7..94d330be8 100644
--- a/src/gui/gui-buffer.h
+++ b/src/gui/gui-buffer.h
@@ -309,8 +309,8 @@ extern void gui_buffer_local_var_add (struct t_gui_buffer *buffer,
                                       const char *value);
 extern void gui_buffer_local_var_remove (struct t_gui_buffer *buffer,
                                          const char *name);
-extern void gui_buffer_notify_set_all ();
-extern long long gui_buffer_generate_id ();
+extern void gui_buffer_notify_set_all (void);
+extern long long gui_buffer_generate_id (void);
 extern int gui_buffer_is_reserved_name (const char *name);
 extern void gui_buffer_apply_config_option_property (struct t_gui_buffer *buffer,
                                                      struct t_config_option *option);
@@ -358,7 +358,7 @@ extern struct t_gui_buffer *gui_buffer_new (struct t_weechat_plugin *plugin,
                                             void *close_callback_data);
 extern struct t_gui_buffer *gui_buffer_new_user (const char *name,
                                                  enum t_gui_buffer_type buffer_type);
-extern void gui_buffer_user_set_callbacks ();
+extern void gui_buffer_user_set_callbacks (void);
 extern int gui_buffer_valid (struct t_gui_buffer *buffer);
 extern char *gui_buffer_string_replace_local_var (struct t_gui_buffer *buffer,
                                                   const char *string);
@@ -399,11 +399,11 @@ extern void gui_buffer_set (struct t_gui_buffer *buffer, const char *property,
                             const char *value);
 extern void gui_buffer_set_pointer (struct t_gui_buffer *buffer,
                                     const char *property, void *pointer);
-extern void gui_buffer_compute_num_displayed ();
+extern void gui_buffer_compute_num_displayed (void);
 extern void gui_buffer_add_value_num_displayed (struct t_gui_buffer *buffer,
                                                 int value);
 extern int gui_buffer_is_main (const char *plugin_name, const char *name);
-extern struct t_gui_buffer *gui_buffer_search_main ();
+extern struct t_gui_buffer *gui_buffer_search_main (void);
 extern struct t_gui_buffer *gui_buffer_search_by_id (long long id);
 extern struct t_gui_buffer *gui_buffer_search_by_full_name (const char *full_name);
 extern struct t_gui_buffer *gui_buffer_search (const char *plugin, const char *name);
@@ -413,7 +413,7 @@ extern struct t_gui_buffer *gui_buffer_search_by_number (int number);
 extern struct t_gui_buffer *gui_buffer_search_by_id_number_name (const char *string);
 extern int gui_buffer_count_merged_buffers (int number);
 extern void gui_buffer_clear (struct t_gui_buffer *buffer);
-extern void gui_buffer_clear_all ();
+extern void gui_buffer_clear_all (void);
 extern void gui_buffer_close (struct t_gui_buffer *buffer);
 extern void gui_buffer_switch_by_number (struct t_gui_window *window,
                                          int number);
@@ -427,12 +427,12 @@ extern void gui_buffer_swap (int number1, int number2);
 extern void gui_buffer_merge (struct t_gui_buffer *buffer,
                               struct t_gui_buffer *target_buffer);
 extern void gui_buffer_unmerge (struct t_gui_buffer *buffer, int number);
-extern void gui_buffer_unmerge_all ();
+extern void gui_buffer_unmerge_all (void);
 extern void gui_buffer_hide (struct t_gui_buffer *buffer);
-extern void gui_buffer_hide_all ();
+extern void gui_buffer_hide_all (void);
 extern void gui_buffer_unhide (struct t_gui_buffer *buffer);
-extern void gui_buffer_unhide_all ();
-extern void gui_buffer_sort_by_layout_number ();
+extern void gui_buffer_unhide_all (void);
+extern void gui_buffer_sort_by_layout_number (void);
 extern void gui_buffer_undo_snap (struct t_gui_buffer *buffer);
 extern void gui_buffer_undo_snap_free (struct t_gui_buffer *buffer);
 extern void gui_buffer_undo_add (struct t_gui_buffer *buffer);
@@ -459,6 +459,6 @@ extern struct t_hdata *gui_buffer_hdata_buffer_visited_cb (const void *pointer,
 extern int gui_buffer_add_to_infolist (struct t_infolist *infolist,
                                        struct t_gui_buffer *buffer);
 extern void gui_buffer_dump_hexa (struct t_gui_buffer *buffer);
-extern void gui_buffer_print_log ();
+extern void gui_buffer_print_log (void);
 
 #endif /* WEECHAT_GUI_BUFFER_H */
diff --git a/src/gui/gui-chat.c b/src/gui/gui-chat.c
index b34d1193b..5c12c38e0 100644
--- a/src/gui/gui-chat.c
+++ b/src/gui/gui-chat.c
@@ -86,7 +86,7 @@ char *gui_chat_pipe_color_string[GUI_CHAT_PIPE_NUM_COLORS] =
  */
 
 void
-gui_chat_init ()
+gui_chat_init (void)
 {
     char *default_prefix[GUI_CHAT_NUM_PREFIXES] =
         { GUI_CHAT_PREFIX_ERROR_DEFAULT, GUI_CHAT_PREFIX_NETWORK_DEFAULT,
@@ -114,7 +114,7 @@ gui_chat_init ()
  */
 
 void
-gui_chat_prefix_build ()
+gui_chat_prefix_build (void)
 {
     const char *ptr_prefix;
     char prefix[512], *pos_color;
@@ -525,7 +525,7 @@ gui_chat_get_time_string (time_t date, int date_usec, int highlight)
  */
 
 int
-gui_chat_get_time_length ()
+gui_chat_get_time_length (void)
 {
     struct timeval tv_now;
     char *text_time;
@@ -553,7 +553,7 @@ gui_chat_get_time_length ()
  */
 
 void
-gui_chat_change_time_format ()
+gui_chat_change_time_format (void)
 {
     struct t_gui_buffer *ptr_buffer;
     struct t_gui_line *ptr_line;
@@ -808,7 +808,7 @@ gui_chat_pipe_handle_line (struct t_gui_line *line)
  */
 
 void
-gui_chat_pipe_end ()
+gui_chat_pipe_end (void)
 {
     struct t_gui_buffer *pipe_buffer;
     struct t_hashtable *hashtable;
@@ -1492,7 +1492,7 @@ gui_chat_hsignal_quote_line_cb (const void *pointer, void *data,
  */
 
 void
-gui_chat_end ()
+gui_chat_end (void)
 {
     int i;
 
diff --git a/src/gui/gui-chat.h b/src/gui/gui-chat.h
index d375092f9..2a23e6885 100644
--- a/src/gui/gui-chat.h
+++ b/src/gui/gui-chat.h
@@ -98,8 +98,8 @@ extern int gui_chat_display_tags;
 
 /* chat functions */
 
-extern void gui_chat_init ();
-extern void gui_chat_prefix_build ();
+extern void gui_chat_init (void);
+extern void gui_chat_prefix_build (void);
 extern int gui_chat_strlen (const char *string);
 extern int gui_chat_strlen_screen (const char *string);
 extern const char *gui_chat_string_add_offset (const char *string, int offset);
@@ -115,12 +115,12 @@ extern void gui_chat_get_word_info (struct t_gui_window *window,
                                     int *word_length);
 extern char *gui_chat_get_time_string (time_t date, int date_usec,
                                        int highlight);
-extern int gui_chat_get_time_length ();
-extern void gui_chat_change_time_format ();
+extern int gui_chat_get_time_length (void);
+extern void gui_chat_change_time_format (void);
 extern int gui_chat_buffer_valid (struct t_gui_buffer *buffer,
                                   int buffer_type);
 extern int gui_chat_pipe_search_color (const char *color);
-extern void gui_chat_pipe_end ();
+extern void gui_chat_pipe_end (void);
 extern void gui_chat_printf_datetime_tags (struct t_gui_buffer *buffer,
                                            time_t date, int date_usec,
                                            const char *tags,
@@ -134,7 +134,7 @@ extern void gui_chat_print_lines_waiting_buffer (FILE *f);
 extern int gui_chat_hsignal_quote_line_cb (const void *pointer, void *data,
                                            const char *signal,
                                            struct t_hashtable *hashtable);
-extern void gui_chat_end ();
+extern void gui_chat_end (void);
 
 /* chat functions (GUI dependent) */
 
diff --git a/src/gui/gui-color.c b/src/gui/gui-color.c
index 83d372eb3..16d5e7901 100644
--- a/src/gui/gui-color.c
+++ b/src/gui/gui-color.c
@@ -1918,7 +1918,7 @@ gui_color_palette_free_value_cb (struct t_hashtable *hashtable,
  */
 
 void
-gui_color_palette_alloc_structs ()
+gui_color_palette_alloc_structs (void)
 {
     if (!gui_color_hash_palette_color)
     {
@@ -2034,7 +2034,7 @@ gui_color_palette_remove (int number)
  */
 
 void
-gui_color_palette_free_structs ()
+gui_color_palette_free_structs (void)
 {
     hashtable_free (gui_color_hash_palette_color);
     hashtable_free (gui_color_hash_palette_alias);
@@ -2046,7 +2046,7 @@ gui_color_palette_free_structs ()
  */
 
 void
-gui_color_init ()
+gui_color_init (void)
 {
     int i;
 
@@ -2061,7 +2061,7 @@ gui_color_init ()
  */
 
 void
-gui_color_end ()
+gui_color_end (void)
 {
     int i;
 
diff --git a/src/gui/gui-color.h b/src/gui/gui-color.h
index 94cdfc1e0..cff4a3dac 100644
--- a/src/gui/gui-color.h
+++ b/src/gui/gui-color.h
@@ -206,13 +206,13 @@ extern char *gui_color_encode_ansi (const char *string);
 extern char *gui_color_emphasize (const char *string, const char *search,
                                   int case_sensitive, regex_t *regex);
 extern void gui_color_free (struct t_gui_color *color);
-extern void gui_color_palette_alloc_structs ();
+extern void gui_color_palette_alloc_structs (void);
 extern int gui_color_palette_get_alias (const char *alias);
 extern struct t_gui_color_palette *gui_color_palette_get (int number);
 extern void gui_color_palette_add (int number, const char *value);
 extern void gui_color_palette_remove (int number);
-extern void gui_color_init ();
-extern void gui_color_end ();
+extern void gui_color_init (void);
+extern void gui_color_end (void);
 
 /* color functions (GUI dependent) */
 
@@ -222,23 +222,23 @@ extern int gui_color_get_extended_flags (int attrs);
 extern int gui_color_assign (int *color, char const *color_name);
 extern int gui_color_assign_by_diff (int *color, const char *color_name,
                                      int diff);
-extern int gui_color_get_weechat_colors_number ();
-extern int gui_color_get_term_colors ();
-extern int gui_color_get_term_color_pairs ();
+extern int gui_color_get_weechat_colors_number (void);
+extern int gui_color_get_term_colors (void);
+extern int gui_color_get_term_color_pairs (void);
 extern const char *gui_color_get_name (int num_color);
-extern void gui_color_free_vars ();
-extern void gui_color_init_weechat ();
-extern void gui_color_display_terminal_colors ();
+extern void gui_color_free_vars (void);
+extern void gui_color_init_weechat (void);
+extern void gui_color_display_terminal_colors (void);
 extern void gui_color_info_term_colors (char *buffer, int size);
-extern void gui_color_buffer_display ();
-extern void gui_color_switch_colors ();
-extern void gui_color_reset_pairs ();
-extern void gui_color_buffer_assign ();
-extern void gui_color_buffer_open ();
-extern void gui_color_palette_build_aliases ();
+extern void gui_color_buffer_display (void);
+extern void gui_color_switch_colors (void);
+extern void gui_color_reset_pairs (void);
+extern void gui_color_buffer_assign (void);
+extern void gui_color_buffer_open (void);
+extern void gui_color_palette_build_aliases (void);
 extern struct t_gui_color_palette *gui_color_palette_new (int number,
                                                           const char *value);
 extern void gui_color_palette_free (struct t_gui_color_palette *color_palette);
-extern void gui_color_dump ();
+extern void gui_color_dump (void);
 
 #endif /* WEECHAT_GUI_COLOR_H */
diff --git a/src/gui/gui-completion.c b/src/gui/gui-completion.c
index 0d6eaa63c..267c72bc9 100644
--- a/src/gui/gui-completion.c
+++ b/src/gui/gui-completion.c
@@ -1714,7 +1714,7 @@ gui_completion_list_words_print_log (struct t_arraylist *list,
  */
 
 void
-gui_completion_print_log ()
+gui_completion_print_log (void)
 {
     struct t_gui_completion *ptr_completion;
 
diff --git a/src/gui/gui-completion.h b/src/gui/gui-completion.h
index fe804520b..ff64714e9 100644
--- a/src/gui/gui-completion.h
+++ b/src/gui/gui-completion.h
@@ -102,6 +102,6 @@ extern struct t_hdata *gui_completion_hdata_completion_cb (const void *pointer,
 extern struct t_hdata *gui_completion_hdata_completion_word_cb (const void *pointer,
                                                                 void *data,
                                                                 const char *hdata_name);
-extern void gui_completion_print_log ();
+extern void gui_completion_print_log (void);
 
 #endif /* WEECHAT_GUI_COMPLETION_H */
diff --git a/src/gui/gui-cursor.c b/src/gui/gui-cursor.c
index 6c43e4384..9d9121a39 100644
--- a/src/gui/gui-cursor.c
+++ b/src/gui/gui-cursor.c
@@ -52,7 +52,7 @@ int gui_cursor_y = 0;                  /* position of cursor in cursor mode */
  */
 
 void
-gui_cursor_mode_toggle ()
+gui_cursor_mode_toggle (void)
 {
     gui_cursor_mode ^= 1;
 
@@ -86,7 +86,7 @@ gui_cursor_mode_toggle ()
  */
 
 void
-gui_cursor_mode_stop ()
+gui_cursor_mode_stop (void)
 {
     if (gui_cursor_mode)
         gui_cursor_mode_toggle ();
@@ -115,7 +115,7 @@ gui_cursor_debug_set (int debug)
  */
 
 void
-gui_cursor_display_debug_info ()
+gui_cursor_display_debug_info (void)
 {
     struct t_gui_focus_info *focus_info;
     char str_info[1024];
diff --git a/src/gui/gui-cursor.h b/src/gui/gui-cursor.h
index b333bdf52..a85f8da03 100644
--- a/src/gui/gui-cursor.h
+++ b/src/gui/gui-cursor.h
@@ -29,8 +29,8 @@ extern int gui_cursor_y;
 
 /* cursor functions */
 
-extern void gui_cursor_mode_toggle ();
-extern void gui_cursor_mode_stop ();
+extern void gui_cursor_mode_toggle (void);
+extern void gui_cursor_mode_stop (void);
 extern void gui_cursor_debug_set (int debug);
 extern void gui_cursor_move_xy (int x, int y);
 extern void gui_cursor_move_add_xy (int add_x, int add_y);
diff --git a/src/gui/gui-filter.c b/src/gui/gui-filter.c
index 4d18168c5..a40d867e9 100644
--- a/src/gui/gui-filter.c
+++ b/src/gui/gui-filter.c
@@ -214,7 +214,7 @@ gui_filter_all_buffers (struct t_gui_filter *filter)
  */
 
 void
-gui_filter_global_enable ()
+gui_filter_global_enable (void)
 {
     if (!gui_filters_enabled)
     {
@@ -230,7 +230,7 @@ gui_filter_global_enable ()
  */
 
 void
-gui_filter_global_disable ()
+gui_filter_global_disable (void)
 {
     if (gui_filters_enabled)
     {
@@ -567,7 +567,7 @@ gui_filter_free (struct t_gui_filter *filter)
  */
 
 void
-gui_filter_free_all ()
+gui_filter_free_all (void)
 {
     while (gui_filters)
     {
@@ -672,7 +672,7 @@ gui_filter_add_to_infolist (struct t_infolist *infolist,
  */
 
 void
-gui_filter_print_log ()
+gui_filter_print_log (void)
 {
     struct t_gui_filter *ptr_filter;
     int i;
diff --git a/src/gui/gui-filter.h b/src/gui/gui-filter.h
index 6b4aa083a..4e28ace9f 100644
--- a/src/gui/gui-filter.h
+++ b/src/gui/gui-filter.h
@@ -57,8 +57,8 @@ extern int gui_filter_check_line (struct t_gui_line_data *line_data);
 extern void gui_filter_buffer (struct t_gui_buffer *buffer,
                                struct t_gui_line_data *line_data);
 extern void gui_filter_all_buffers (struct t_gui_filter *filter);
-extern void gui_filter_global_enable ();
-extern void gui_filter_global_disable ();
+extern void gui_filter_global_enable (void);
+extern void gui_filter_global_disable (void);
 extern struct t_gui_filter *gui_filter_search_by_name (const char *name);
 extern struct t_gui_filter *gui_filter_new (int enabled,
                                             const char *name,
@@ -68,12 +68,12 @@ extern struct t_gui_filter *gui_filter_new (int enabled,
 extern int gui_filter_rename (struct t_gui_filter *filter,
                               const char *new_name);
 extern void gui_filter_free (struct t_gui_filter *filter);
-extern void gui_filter_free_all ();
+extern void gui_filter_free_all (void);
 extern struct t_hdata *gui_filter_hdata_filter_cb (const void *pointer,
                                                    void *data,
                                                    const char *hdata_name);
 extern int gui_filter_add_to_infolist (struct t_infolist *infolist,
                                        struct t_gui_filter *filter);
-extern void gui_filter_print_log ();
+extern void gui_filter_print_log (void);
 
 #endif /* WEECHAT_GUI_FILTER_H */
diff --git a/src/gui/gui-history.c b/src/gui/gui-history.c
index 8d131a59c..dd544273a 100644
--- a/src/gui/gui-history.c
+++ b/src/gui/gui-history.c
@@ -118,7 +118,7 @@ gui_history_buffer_add (struct t_gui_buffer *buffer, const char *string)
  */
 
 void
-gui_history_global_remove_oldest ()
+gui_history_global_remove_oldest (void)
 {
     struct t_gui_buffer *ptr_buffer;
     struct t_gui_history *ptr_history;
@@ -300,7 +300,7 @@ gui_history_search (struct t_gui_buffer *buffer,
  */
 
 void
-gui_history_global_free ()
+gui_history_global_free (void)
 {
     struct t_gui_history *ptr_history;
 
diff --git a/src/gui/gui-history.h b/src/gui/gui-history.h
index df6305b22..5ae674cd6 100644
--- a/src/gui/gui-history.h
+++ b/src/gui/gui-history.h
@@ -39,7 +39,7 @@ extern void gui_history_global_add (const char *string);
 extern void gui_history_add (struct t_gui_buffer *buffer, const char *string);
 extern int gui_history_search (struct t_gui_buffer *buffer,
                                struct t_gui_history *history);
-extern void gui_history_global_free ();
+extern void gui_history_global_free (void);
 extern void gui_history_buffer_free (struct t_gui_buffer *buffer);
 extern struct t_hdata *gui_history_hdata_history_cb (const void *pointer,
                                                      void *data,
diff --git a/src/gui/gui-hotlist.c b/src/gui/gui-hotlist.c
index 4e063dbaf..31733ad52 100644
--- a/src/gui/gui-hotlist.c
+++ b/src/gui/gui-hotlist.c
@@ -525,7 +525,7 @@ gui_hotlist_restore_buffer (struct t_gui_buffer *buffer)
  */
 
 void
-gui_hotlist_restore_all_buffers ()
+gui_hotlist_restore_all_buffers (void)
 {
     struct t_gui_buffer *ptr_buffer;
 
@@ -541,7 +541,7 @@ gui_hotlist_restore_all_buffers ()
  */
 
 void
-gui_hotlist_resort ()
+gui_hotlist_resort (void)
 {
     struct t_gui_hotlist *new_hotlist, *last_new_hotlist;
     struct t_gui_hotlist *ptr_hotlist, *ptr_next_hotlist, *ptr_prev_hotlist;
@@ -841,7 +841,7 @@ gui_hotlist_add_to_infolist (struct t_infolist *infolist,
  */
 
 void
-gui_hotlist_print_log ()
+gui_hotlist_print_log (void)
 {
     struct t_gui_hotlist *ptr_hotlist;
     int i;
@@ -869,7 +869,7 @@ gui_hotlist_print_log ()
  */
 
 void
-gui_hotlist_end ()
+gui_hotlist_end (void)
 {
     if (gui_hotlist_hashtable_add_conditions_pointers)
     {
diff --git a/src/gui/gui-hotlist.h b/src/gui/gui-hotlist.h
index a8f84a48b..bc3e5a80b 100644
--- a/src/gui/gui-hotlist.h
+++ b/src/gui/gui-hotlist.h
@@ -64,8 +64,8 @@ extern struct t_gui_hotlist *gui_hotlist_add (struct t_gui_buffer *buffer,
                                               struct timeval *creation_time,
                                               int check_conditions);
 extern void gui_hotlist_restore_buffer (struct t_gui_buffer *buffer);
-extern void gui_hotlist_restore_all_buffers ();
-extern void gui_hotlist_resort ();
+extern void gui_hotlist_restore_all_buffers (void);
+extern void gui_hotlist_resort (void);
 extern void gui_hotlist_clear (int level_mask);
 extern void gui_hotlist_clear_level_string (struct t_gui_buffer *buffer,
                                             const char *str_level_mask);
@@ -76,7 +76,7 @@ extern struct t_hdata *gui_hotlist_hdata_hotlist_cb (const void *pointer,
                                                      const char *hdata_name);
 extern int gui_hotlist_add_to_infolist (struct t_infolist *infolist,
                                         struct t_gui_hotlist *hotlist);
-extern void gui_hotlist_print_log ();
-extern void gui_hotlist_end ();
+extern void gui_hotlist_print_log (void);
+extern void gui_hotlist_end (void);
 
 #endif /* WEECHAT_GUI_HOTLIST_H */
diff --git a/src/gui/gui-input.c b/src/gui/gui-input.c
index ace0e79d9..99d0bf5b4 100644
--- a/src/gui/gui-input.c
+++ b/src/gui/gui-input.c
@@ -123,7 +123,7 @@ gui_input_replace_input (struct t_gui_buffer *buffer, const char *new_input)
  */
 
 void
-gui_input_paste_pending_signal ()
+gui_input_paste_pending_signal (void)
 {
     if (CONFIG_BOOLEAN(config_look_bare_display_exit_on_input)
         && gui_window_bare_display)
diff --git a/src/gui/gui-input.h b/src/gui/gui-input.h
index b7d1303dc..fc37b8907 100644
--- a/src/gui/gui-input.h
+++ b/src/gui/gui-input.h
@@ -30,7 +30,7 @@ extern char *gui_input_clipboard;
 
 extern void gui_input_replace_input (struct t_gui_buffer *buffer,
                                      const char *new_input);
-extern void gui_input_paste_pending_signal ();
+extern void gui_input_paste_pending_signal (void);
 extern void gui_input_text_changed_modifier_and_signal (struct t_gui_buffer *buffer,
                                                         int save_undo,
                                                         int stop_completion);
diff --git a/src/gui/gui-key.c b/src/gui/gui-key.c
index b395524fc..be82fd08b 100644
--- a/src/gui/gui-key.c
+++ b/src/gui/gui-key.c
@@ -111,7 +111,7 @@ time_t gui_key_last_activity_time = 0; /* last activity time (key)          */
  */
 
 void
-gui_key_init ()
+gui_key_init (void)
 {
     int context;
 
@@ -168,7 +168,7 @@ gui_key_search_context (const char *context)
  */
 
 int
-gui_key_get_current_context ()
+gui_key_get_current_context (void)
 {
     if (gui_cursor_mode)
         return GUI_KEY_CONTEXT_CURSOR;
@@ -2680,7 +2680,7 @@ gui_key_free_all (int context, struct t_gui_key **keys,
  */
 
 void
-gui_key_buffer_optimize ()
+gui_key_buffer_optimize (void)
 {
     int optimal_size, *gui_key_buffer2;
 
@@ -2711,7 +2711,7 @@ gui_key_buffer_optimize ()
  */
 
 void
-gui_key_buffer_reset ()
+gui_key_buffer_reset (void)
 {
     if (!gui_key_buffer)
     {
@@ -2827,7 +2827,7 @@ gui_key_buffer_remove (int index, int number)
  */
 
 void
-gui_key_paste_remove_newline ()
+gui_key_paste_remove_newline (void)
 {
     if ((gui_key_buffer_size > 0)
         && ((gui_key_buffer[gui_key_buffer_size - 1] == '\r')
@@ -2843,7 +2843,7 @@ gui_key_paste_remove_newline ()
  */
 
 void
-gui_key_paste_replace_tabs ()
+gui_key_paste_replace_tabs (void)
 {
     int i;
 
@@ -2859,7 +2859,7 @@ gui_key_paste_replace_tabs ()
  */
 
 void
-gui_key_paste_start ()
+gui_key_paste_start (void)
 {
     gui_key_paste_pending = 1;
     gui_input_paste_pending_signal ();
@@ -2870,7 +2870,7 @@ gui_key_paste_start ()
  */
 
 void
-gui_key_paste_finish ()
+gui_key_paste_finish (void)
 {
     gui_key_paste_remove_newline ();
     gui_key_paste_replace_tabs ();
@@ -2883,7 +2883,7 @@ gui_key_paste_finish ()
  */
 
 int
-gui_key_get_paste_lines ()
+gui_key_get_paste_lines (void)
 {
     int length;
 
@@ -2968,7 +2968,7 @@ gui_key_paste_bracketed_timer_cb (const void *pointer, void *data,
  */
 
 void
-gui_key_paste_bracketed_timer_remove ()
+gui_key_paste_bracketed_timer_remove (void)
 {
     if (gui_key_paste_bracketed_timer)
     {
@@ -2982,7 +2982,7 @@ gui_key_paste_bracketed_timer_remove ()
  */
 
 void
-gui_key_paste_bracketed_timer_add ()
+gui_key_paste_bracketed_timer_add (void)
 {
     gui_key_paste_bracketed_timer_remove ();
     gui_key_paste_bracketed_timer = hook_timer (
@@ -2997,7 +2997,7 @@ gui_key_paste_bracketed_timer_add ()
  */
 
 void
-gui_key_paste_bracketed_start ()
+gui_key_paste_bracketed_start (void)
 {
     gui_key_paste_bracketed = 1;
     gui_key_paste_bracketed_timer_add ();
@@ -3009,7 +3009,7 @@ gui_key_paste_bracketed_start ()
  */
 
 void
-gui_key_paste_bracketed_stop ()
+gui_key_paste_bracketed_stop (void)
 {
     gui_key_paste_check (1);
     gui_key_paste_bracketed = 0;
@@ -3020,7 +3020,7 @@ gui_key_paste_bracketed_stop ()
  */
 
 void
-gui_key_paste_accept ()
+gui_key_paste_accept (void)
 {
     gui_key_paste_pending = 0;
     gui_input_paste_pending_signal ();
@@ -3032,7 +3032,7 @@ gui_key_paste_accept ()
  */
 
 void
-gui_key_paste_cancel ()
+gui_key_paste_cancel (void)
 {
     gui_key_buffer_reset ();
     gui_key_paste_pending = 0;
@@ -3044,7 +3044,7 @@ gui_key_paste_cancel ()
  */
 
 void
-gui_key_end ()
+gui_key_end (void)
 {
     int context;
 
diff --git a/src/gui/gui-key.h b/src/gui/gui-key.h
index d997d2873..e6e6e97f3 100644
--- a/src/gui/gui-key.h
+++ b/src/gui/gui-key.h
@@ -90,7 +90,7 @@ extern time_t gui_key_last_activity_time;
 
 /* key functions */
 
-extern void gui_key_init ();
+extern void gui_key_init (void);
 extern int gui_key_search_context (const char *context);
 extern void gui_key_grab_init (int grab_command, const char *delay);
 extern int gui_key_expand (const char *key,
@@ -128,24 +128,24 @@ extern void gui_key_free_all (int context,
                               struct t_gui_key **last_key,
                               int *keys_count,
                               int delete_option);
-extern void gui_key_buffer_reset ();
+extern void gui_key_buffer_reset (void);
 extern void gui_key_buffer_add (unsigned char key);
 extern int gui_key_buffer_search (int start_index, int max_index,
                                   const char *string);
 extern void gui_key_buffer_remove (int index, int number);
-extern void gui_key_paste_remove_newline ();
-extern void gui_key_paste_replace_tabs ();
-extern void gui_key_paste_start ();
-extern void gui_key_paste_finish ();
-extern int gui_key_get_paste_lines ();
+extern void gui_key_paste_remove_newline (void);
+extern void gui_key_paste_replace_tabs (void);
+extern void gui_key_paste_start (void);
+extern void gui_key_paste_finish (void);
+extern int gui_key_get_paste_lines (void);
 extern int gui_key_paste_check (int bracketed_paste);
-extern void gui_key_paste_bracketed_timer_remove ();
-extern void gui_key_paste_bracketed_timer_add ();
-extern void gui_key_paste_bracketed_start ();
-extern void gui_key_paste_bracketed_stop ();
-extern void gui_key_paste_accept ();
-extern void gui_key_paste_cancel ();
-extern void gui_key_end ();
+extern void gui_key_paste_bracketed_timer_remove (void);
+extern void gui_key_paste_bracketed_timer_add (void);
+extern void gui_key_paste_bracketed_start (void);
+extern void gui_key_paste_bracketed_stop (void);
+extern void gui_key_paste_accept (void);
+extern void gui_key_paste_cancel (void);
+extern void gui_key_end (void);
 extern struct t_hdata *gui_key_hdata_key_cb (const void *pointer,
                                              void *data,
                                              const char *hdata_name);
diff --git a/src/gui/gui-layout.c b/src/gui/gui-layout.c
index 2afb409e9..5dd8f8e6a 100644
--- a/src/gui/gui-layout.c
+++ b/src/gui/gui-layout.c
@@ -198,7 +198,7 @@ gui_layout_buffer_remove_all (struct t_gui_layout *layout)
  */
 
 void
-gui_layout_buffer_reset ()
+gui_layout_buffer_reset (void)
 {
     struct t_gui_buffer *ptr_buffer;
 
@@ -419,7 +419,7 @@ gui_layout_window_remove_all (struct t_gui_layout *layout)
  */
 
 void
-gui_layout_window_reset ()
+gui_layout_window_reset (void)
 {
     struct t_gui_window *ptr_win;
 
@@ -652,7 +652,7 @@ gui_layout_window_assign_buffer (struct t_gui_buffer *buffer)
  */
 
 void
-gui_layout_window_assign_all_buffers ()
+gui_layout_window_assign_all_buffers (void)
 {
     struct t_gui_window *ptr_win;
     struct t_gui_buffer *ptr_buffer;
@@ -768,7 +768,7 @@ gui_layout_window_apply (struct t_gui_layout *layout,
  */
 
 void
-gui_layout_store_on_exit ()
+gui_layout_store_on_exit (void)
 {
     struct t_gui_layout *ptr_layout;
 
@@ -874,7 +874,7 @@ gui_layout_remove (struct t_gui_layout *layout)
  */
 
 void
-gui_layout_remove_all ()
+gui_layout_remove_all (void)
 {
     while (gui_layouts)
     {
@@ -1116,7 +1116,7 @@ gui_layout_print_log_window (struct t_gui_layout_window *layout_window,
  */
 
 void
-gui_layout_print_log ()
+gui_layout_print_log (void)
 {
     struct t_gui_layout *ptr_layout;
     struct t_gui_layout_buffer *ptr_layout_buffer;
diff --git a/src/gui/gui-layout.h b/src/gui/gui-layout.h
index 95957a0ff..b312d8a5a 100644
--- a/src/gui/gui-layout.h
+++ b/src/gui/gui-layout.h
@@ -79,7 +79,7 @@ extern struct t_gui_layout *gui_layout_alloc (const char *name);
 extern int gui_layout_add (struct t_gui_layout *layout);
 extern void gui_layout_rename (struct t_gui_layout *layout, const char *new_name);
 extern void gui_layout_buffer_remove_all (struct t_gui_layout *layout);
-extern void gui_layout_buffer_reset ();
+extern void gui_layout_buffer_reset (void);
 extern struct t_gui_layout_buffer *gui_layout_buffer_add (struct t_gui_layout *layout,
                                                           const char *plugin_name,
                                                           const char *buffer_name,
@@ -94,7 +94,7 @@ extern void gui_layout_buffer_store (struct t_gui_layout *layout);
 extern void gui_layout_buffer_apply (struct t_gui_layout *layout);
 
 extern void gui_layout_window_remove_all (struct t_gui_layout *layout);
-extern void gui_layout_window_reset ();
+extern void gui_layout_window_reset (void);
 extern struct t_gui_layout_window *gui_layout_window_search_by_id (struct t_gui_layout_window *layout_window,
                                                                    int id);
 extern struct t_gui_layout_window *gui_layout_window_add (struct t_gui_layout_window **layout_window,
@@ -109,10 +109,10 @@ extern int gui_layout_window_check_buffer (struct t_gui_window *window);
 extern void gui_layout_window_assign_buffer (struct t_gui_buffer *buffer);
 extern void gui_layout_window_apply (struct t_gui_layout *layout,
                                      int internal_id_current_window);
-extern void gui_layout_store_on_exit ();
+extern void gui_layout_store_on_exit (void);
 extern void gui_layout_free (struct t_gui_layout *layout);
 extern void gui_layout_remove (struct t_gui_layout *layout);
-extern void gui_layout_remove_all ();
+extern void gui_layout_remove_all (void);
 extern struct t_hdata *gui_layout_hdata_layout_buffer_cb (const void *pointer,
                                                           void *data,
                                                           const char *hdata_name);
@@ -128,6 +128,6 @@ extern int gui_layout_window_add_to_infolist (struct t_infolist *infolist,
                                               struct t_gui_layout_window *layout_window);
 extern int gui_layout_add_to_infolist (struct t_infolist *infolist,
                                        struct t_gui_layout *layout);
-extern void gui_layout_print_log ();
+extern void gui_layout_print_log (void);
 
 #endif /* WEECHAT_GUI_LAYOUT_H */
diff --git a/src/gui/gui-line.c b/src/gui/gui-line.c
index 43158c57f..9db1f09fb 100644
--- a/src/gui/gui-line.c
+++ b/src/gui/gui-line.c
@@ -55,7 +55,7 @@
  */
 
 struct t_gui_lines *
-gui_line_lines_alloc ()
+gui_line_lines_alloc (void)
 {
     struct t_gui_lines *new_lines;
 
diff --git a/src/gui/gui-line.h b/src/gui/gui-line.h
index 184290728..a3d5d660d 100644
--- a/src/gui/gui-line.h
+++ b/src/gui/gui-line.h
@@ -74,7 +74,7 @@ struct t_gui_lines
 
 /* line functions */
 
-extern struct t_gui_lines *gui_line_lines_alloc ();
+extern struct t_gui_lines *gui_line_lines_alloc (void);
 extern void gui_line_lines_free (struct t_gui_lines *lines);
 extern void gui_line_tags_alloc (struct t_gui_line_data *line_data,
                                  const char *tags);
diff --git a/src/gui/gui-main.h b/src/gui/gui-main.h
index 4f7cda3e4..61edf9811 100644
--- a/src/gui/gui-main.h
+++ b/src/gui/gui-main.h
@@ -24,7 +24,7 @@
 
 extern void gui_main_get_password (const char **prompt,
                                    char *password, int size);
-extern void gui_main_debug_libs ();
+extern void gui_main_debug_libs (void);
 extern void gui_main_end (int clean_exit);
 
 /* terminal functions (GUI dependent) */
diff --git a/src/gui/gui-mouse.c b/src/gui/gui-mouse.c
index a13aed85b..3b9e169ba 100644
--- a/src/gui/gui-mouse.c
+++ b/src/gui/gui-mouse.c
@@ -67,7 +67,7 @@ gui_mouse_debug_set (int debug)
  */
 
 void
-gui_mouse_event_reset ()
+gui_mouse_event_reset (void)
 {
     gui_mouse_event_index = 0;
     gui_mouse_event_x[0] = 0;
diff --git a/src/gui/gui-mouse.h b/src/gui/gui-mouse.h
index 81b3c210c..c9560fe48 100644
--- a/src/gui/gui-mouse.h
+++ b/src/gui/gui-mouse.h
@@ -34,13 +34,13 @@ extern char gui_mouse_event_button;
 /* mouse functions */
 
 extern void gui_mouse_debug_set (int debug);
-extern void gui_mouse_event_reset ();
+extern void gui_mouse_event_reset (void);
 
 /* mouse functions (GUI dependent) */
 
-extern void gui_mouse_enable ();
-extern void gui_mouse_disable ();
-extern void gui_mouse_display_state ();
+extern void gui_mouse_enable (void);
+extern void gui_mouse_disable (void);
+extern void gui_mouse_display_state (void);
 extern void gui_mouse_grab_init (int area);
 extern int gui_mouse_event_size (const char *key);
 extern void gui_mouse_event_process (const char *key);
diff --git a/src/gui/gui-nicklist.c b/src/gui/gui-nicklist.c
index 7cc6071c9..bad94fc60 100644
--- a/src/gui/gui-nicklist.c
+++ b/src/gui/gui-nicklist.c
@@ -1541,7 +1541,7 @@ gui_nicklist_print_log (struct t_gui_nick_group *group, int indent)
  */
 
 void
-gui_nicklist_end ()
+gui_nicklist_end (void)
 {
     if (gui_nicklist_hsignal)
     {
diff --git a/src/gui/gui-nicklist.h b/src/gui/gui-nicklist.h
index 7fc1408d8..adbd597aa 100644
--- a/src/gui/gui-nicklist.h
+++ b/src/gui/gui-nicklist.h
@@ -135,6 +135,6 @@ extern int gui_nicklist_add_to_infolist (struct t_infolist *infolist,
                                          struct t_gui_buffer *buffer,
                                          const char *name);
 extern void gui_nicklist_print_log (struct t_gui_nick_group *group, int indent);
-extern void gui_nicklist_end ();
+extern void gui_nicklist_end (void);
 
 #endif /* WEECHAT_GUI_NICKLIST_H */
diff --git a/src/gui/gui-window.c b/src/gui/gui-window.c
index 3f6d75d6e..4803c0697 100644
--- a/src/gui/gui-window.c
+++ b/src/gui/gui-window.c
@@ -2099,7 +2099,7 @@ gui_window_add_to_infolist (struct t_infolist *infolist,
  */
 
 void
-gui_window_print_log ()
+gui_window_print_log (void)
 {
     struct t_gui_window *ptr_window;
     struct t_gui_window_scroll *ptr_scroll;
diff --git a/src/gui/gui-window.h b/src/gui/gui-window.h
index c2d129bb5..c0501c18d 100644
--- a/src/gui/gui-window.h
+++ b/src/gui/gui-window.h
@@ -206,12 +206,12 @@ extern struct t_hdata *gui_window_hdata_window_tree_cb (const void *pointer,
                                                         const char *hdata_name);
 extern int gui_window_add_to_infolist (struct t_infolist *infolist,
                                        struct t_gui_window *window);
-extern void gui_window_print_log ();
+extern void gui_window_print_log (void);
 
 /* window functions (GUI dependent) */
 
-extern int gui_window_get_width ();
-extern int gui_window_get_height ();
+extern int gui_window_get_width (void);
+extern int gui_window_get_height (void);
 extern int gui_window_objects_init (struct t_gui_window *window);
 extern void gui_window_objects_free (struct t_gui_window *window,
                                      int free_separators);
@@ -249,8 +249,8 @@ extern void gui_window_set_title (const char *title);
 extern void gui_window_send_clipboard (const char *storage_unit,
                                        const char *text);
 extern void gui_window_set_bracketed_paste_mode (int enable);
-extern void gui_window_move_cursor ();
-extern void gui_window_term_display_infos ();
+extern void gui_window_move_cursor (void);
+extern void gui_window_term_display_infos (void);
 extern void gui_window_objects_print_log (struct t_gui_window *window);
 
 #endif /* WEECHAT_GUI_WINDOW_H */
diff --git a/src/plugins/alias/alias-command.c b/src/plugins/alias/alias-command.c
index 6180a29da..9f5653ebb 100644
--- a/src/plugins/alias/alias-command.c
+++ b/src/plugins/alias/alias-command.c
@@ -350,7 +350,7 @@ alias_command_cb (const void *pointer, void *data,
  */
 
 void
-alias_command_init ()
+alias_command_init (void)
 {
     struct t_hook *ptr_hook;
 
diff --git a/src/plugins/alias/alias-command.h b/src/plugins/alias/alias-command.h
index 994cb7988..9e3345d55 100644
--- a/src/plugins/alias/alias-command.h
+++ b/src/plugins/alias/alias-command.h
@@ -22,6 +22,6 @@
 
 #define ALIAS_COMMAND_KEEP_SPACES weechat_hook_set (ptr_hook, "keep_spaces_right", "1")
 
-extern void alias_command_init ();
+extern void alias_command_init (void);
 
 #endif /* WEECHAT_PLUGIN_ALIAS_COMMAND_H */
diff --git a/src/plugins/alias/alias-completion.c b/src/plugins/alias/alias-completion.c
index 0fafeec6b..86f358bfa 100644
--- a/src/plugins/alias/alias-completion.c
+++ b/src/plugins/alias/alias-completion.c
@@ -115,7 +115,7 @@ alias_completion_alias_value_cb (const void *pointer, void *data,
  */
 
 void
-alias_completion_init ()
+alias_completion_init (void)
 {
     weechat_hook_completion ("alias", N_("list of aliases"),
                              &alias_completion_alias_cb, NULL, NULL);
diff --git a/src/plugins/alias/alias-completion.h b/src/plugins/alias/alias-completion.h
index 53fd0e740..6b3d8400d 100644
--- a/src/plugins/alias/alias-completion.h
+++ b/src/plugins/alias/alias-completion.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_ALIAS_COMPLETION_H
 #define WEECHAT_PLUGIN_ALIAS_COMPLETION_H
 
-extern void alias_completion_init ();
+extern void alias_completion_init (void);
 
 #endif /* WEECHAT_PLUGIN_ALIAS_COMPLETION_H */
diff --git a/src/plugins/alias/alias-config.c b/src/plugins/alias/alias-config.c
index 70d94b0ce..a8bad518d 100644
--- a/src/plugins/alias/alias-config.c
+++ b/src/plugins/alias/alias-config.c
@@ -427,7 +427,7 @@ alias_config_update_cb (const void *pointer, void *data,
  */
 
 int
-alias_config_init ()
+alias_config_init (void)
 {
     alias_config_file = weechat_config_new (ALIAS_CONFIG_PRIO_NAME,
                                             &alias_config_reload, NULL, NULL);
@@ -470,7 +470,7 @@ alias_config_init ()
  */
 
 int
-alias_config_read ()
+alias_config_read (void)
 {
     return weechat_config_read (alias_config_file);
 }
@@ -480,7 +480,7 @@ alias_config_read ()
  */
 
 int
-alias_config_write ()
+alias_config_write (void)
 {
     return weechat_config_write (alias_config_file);
 }
diff --git a/src/plugins/alias/alias-config.h b/src/plugins/alias/alias-config.h
index b38a90b0b..277e3f3f7 100644
--- a/src/plugins/alias/alias-config.h
+++ b/src/plugins/alias/alias-config.h
@@ -35,8 +35,8 @@ extern void alias_config_cmd_new_option (const char *name,
                                          const char *command);
 extern void alias_config_completion_new_option (const char *name,
                                                 const char *completion);
-extern int alias_config_init ();
-extern int alias_config_read ();
-extern int alias_config_write ();
+extern int alias_config_init (void);
+extern int alias_config_read (void);
+extern int alias_config_write (void);
 
 #endif /* WEECHAT_PLUGIN_ALIAS_CONFIG_H */
diff --git a/src/plugins/alias/alias-info.c b/src/plugins/alias/alias-info.c
index 26373bde8..2b63cfad0 100644
--- a/src/plugins/alias/alias-info.c
+++ b/src/plugins/alias/alias-info.c
@@ -139,7 +139,7 @@ alias_info_infolist_alias_default_cb (const void *pointer, void *data,
  */
 
 void
-alias_info_init ()
+alias_info_init (void)
 {
     weechat_hook_infolist (
         "alias", N_("list of aliases"),
diff --git a/src/plugins/alias/alias-info.h b/src/plugins/alias/alias-info.h
index b235cfd4b..65fbaeed9 100644
--- a/src/plugins/alias/alias-info.h
+++ b/src/plugins/alias/alias-info.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_ALIAS_INFO_H
 #define WEECHAT_PLUGIN_ALIAS_INFO_H
 
-extern void alias_info_init ();
+extern void alias_info_init (void);
 
 #endif /* WEECHAT_PLUGIN_ALIAS_INFO_H */
diff --git a/src/plugins/alias/alias.c b/src/plugins/alias/alias.c
index 9d7b711ba..611f87fd1 100644
--- a/src/plugins/alias/alias.c
+++ b/src/plugins/alias/alias.c
@@ -606,7 +606,7 @@ alias_free (struct t_alias *alias)
  */
 
 void
-alias_free_all ()
+alias_free_all (void)
 {
     while (alias_list)
     {
diff --git a/src/plugins/alias/alias.h b/src/plugins/alias/alias.h
index 4d97f5079..98d42fa44 100644
--- a/src/plugins/alias/alias.h
+++ b/src/plugins/alias/alias.h
@@ -48,7 +48,7 @@ extern struct t_alias *alias_new (const char *name, const char *command,
                                   const char *completion);
 extern int alias_rename (struct t_alias *alias, const char *new_name);
 extern void alias_free (struct t_alias *alias);
-extern void alias_free_all ();
+extern void alias_free_all (void);
 extern int alias_add_to_infolist (struct t_infolist *infolist,
                                   struct t_alias *alias);
 
diff --git a/src/plugins/buflist/buflist-bar-item.c b/src/plugins/buflist/buflist-bar-item.c
index 8af98b416..6c98a9dd4 100644
--- a/src/plugins/buflist/buflist-bar-item.c
+++ b/src/plugins/buflist/buflist-bar-item.c
@@ -699,7 +699,7 @@ end:
  */
 
 int
-buflist_bar_item_init ()
+buflist_bar_item_init (void)
 {
     int i;
 
@@ -758,7 +758,7 @@ buflist_bar_item_init ()
  */
 
 void
-buflist_bar_item_end ()
+buflist_bar_item_end (void)
 {
     int i;
 
diff --git a/src/plugins/buflist/buflist-bar-item.h b/src/plugins/buflist/buflist-bar-item.h
index 350d23b49..22a40cfb1 100644
--- a/src/plugins/buflist/buflist-bar-item.h
+++ b/src/plugins/buflist/buflist-bar-item.h
@@ -33,7 +33,7 @@ extern const char *buflist_bar_item_get_name (int index);
 extern int buflist_bar_item_get_index (const char *item_name);
 extern int buflist_bar_item_get_index_with_pointer (struct t_gui_bar_item *item);
 extern void buflist_bar_item_update (int index, int force);
-extern int buflist_bar_item_init ();
-extern void buflist_bar_item_end ();
+extern int buflist_bar_item_init (void);
+extern void buflist_bar_item_end (void);
 
 #endif /* WEECHAT_PLUGIN_BUFLIST_BAR_ITEM_H */
diff --git a/src/plugins/buflist/buflist-command.c b/src/plugins/buflist/buflist-command.c
index 7b36c8c21..cf47d1759 100644
--- a/src/plugins/buflist/buflist-command.c
+++ b/src/plugins/buflist/buflist-command.c
@@ -99,7 +99,7 @@ buflist_command_buflist (const void *pointer, void *data,
  */
 
 void
-buflist_command_init ()
+buflist_command_init (void)
 {
     weechat_hook_command (
         "buflist",
diff --git a/src/plugins/buflist/buflist-command.h b/src/plugins/buflist/buflist-command.h
index d00a6f04a..37d3e6581 100644
--- a/src/plugins/buflist/buflist-command.h
+++ b/src/plugins/buflist/buflist-command.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_BUFLIST_COMMAND_H
 #define WEECHAT_PLUGIN_BUFLIST_COMMAND_H
 
-extern void buflist_command_init ();
+extern void buflist_command_init (void);
 
 #endif /* WEECHAT_PLUGIN_BUFLIST_COMMAND_H */
diff --git a/src/plugins/buflist/buflist-completion.c b/src/plugins/buflist/buflist-completion.c
index e6c97a32c..d8ee778a6 100644
--- a/src/plugins/buflist/buflist-completion.c
+++ b/src/plugins/buflist/buflist-completion.c
@@ -88,7 +88,7 @@ buflist_completion_items_used_cb (const void *pointer, void *data,
  */
 
 void
-buflist_completion_init ()
+buflist_completion_init (void)
 {
     weechat_hook_completion ("buflist_items",
                              N_("buflist bar items"),
diff --git a/src/plugins/buflist/buflist-completion.h b/src/plugins/buflist/buflist-completion.h
index d30b44e3c..22df3563f 100644
--- a/src/plugins/buflist/buflist-completion.h
+++ b/src/plugins/buflist/buflist-completion.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_BUFLIST_COMPLETION_H
 #define WEECHAT_PLUGIN_BUFLIST_COMPLETION_H
 
-extern void buflist_completion_init ();
+extern void buflist_completion_init (void);
 
 #endif /* WEECHAT_PLUGIN_BUFLIST_COMPLETION_H */
diff --git a/src/plugins/buflist/buflist-config.c b/src/plugins/buflist/buflist-config.c
index 7a1030eb8..d6ca3b7d5 100644
--- a/src/plugins/buflist/buflist-config.c
+++ b/src/plugins/buflist/buflist-config.c
@@ -105,7 +105,7 @@ buflist_config_reload (const void *pointer, void *data,
  */
 
 void
-buflist_config_free_signals_refresh ()
+buflist_config_free_signals_refresh (void)
 {
     int i;
 
@@ -169,7 +169,7 @@ buflist_config_signal_buffer_cb (const void *pointer, void *data,
  */
 
 void
-buflist_config_hook_signals_refresh ()
+buflist_config_hook_signals_refresh (void)
 {
     char **all_signals, **signals;
     const char *ptr_signals_refresh;
@@ -469,7 +469,7 @@ buflist_config_change_format (const void *pointer, void *data,
  */
 
 int
-buflist_config_init ()
+buflist_config_init (void)
 {
     buflist_config_file = weechat_config_new (
         BUFLIST_CONFIG_PRIO_NAME,
@@ -804,7 +804,7 @@ buflist_config_init ()
  */
 
 int
-buflist_config_read ()
+buflist_config_read (void)
 {
     int rc;
 
@@ -825,7 +825,7 @@ buflist_config_read ()
  */
 
 int
-buflist_config_write ()
+buflist_config_write (void)
 {
     return weechat_config_write (buflist_config_file);
 }
@@ -835,7 +835,7 @@ buflist_config_write ()
  */
 
 void
-buflist_config_free ()
+buflist_config_free (void)
 {
     int i;
 
diff --git a/src/plugins/buflist/buflist-config.h b/src/plugins/buflist/buflist-config.h
index 86bb437bd..abcd9801e 100644
--- a/src/plugins/buflist/buflist-config.h
+++ b/src/plugins/buflist/buflist-config.h
@@ -69,9 +69,9 @@ extern char *buflist_config_format_hotlist_eval;
 
 extern void buflist_config_change_sort (const void *pointer, void *data,
                                         struct t_config_option *option);
-extern int buflist_config_init ();
-extern int buflist_config_read ();
-extern int buflist_config_write ();
-extern void buflist_config_free ();
+extern int buflist_config_init (void);
+extern int buflist_config_read (void);
+extern int buflist_config_write (void);
+extern void buflist_config_free (void);
 
 #endif /* WEECHAT_PLUGIN_BUFLIST_CONFIG_H */
diff --git a/src/plugins/buflist/buflist-info.c b/src/plugins/buflist/buflist-info.c
index 1d9915499..aca4ae01b 100644
--- a/src/plugins/buflist/buflist-info.c
+++ b/src/plugins/buflist/buflist-info.c
@@ -114,7 +114,7 @@ buflist_info_infolist_buflist_cb (const void *pointer, void *data,
  */
 
 void
-buflist_info_init ()
+buflist_info_init (void)
 {
     weechat_hook_infolist (
         "buflist", N_("list of buffers in a buflist bar item"),
diff --git a/src/plugins/buflist/buflist-info.h b/src/plugins/buflist/buflist-info.h
index 6dc6de7ba..fddf2ac65 100644
--- a/src/plugins/buflist/buflist-info.h
+++ b/src/plugins/buflist/buflist-info.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_BUFLIST_INFO_H
 #define WEECHAT_PLUGIN_BUFLIST_INFO_H
 
-extern void buflist_info_init ();
+extern void buflist_info_init (void);
 
 #endif /* WEECHAT_PLUGIN_BUFLIST_INFO_H */
diff --git a/src/plugins/buflist/buflist-mouse.c b/src/plugins/buflist/buflist-mouse.c
index 405fecba7..aa917c3f3 100644
--- a/src/plugins/buflist/buflist-mouse.c
+++ b/src/plugins/buflist/buflist-mouse.c
@@ -437,7 +437,7 @@ buflist_hsignal_cb (const void *pointer, void *data, const char *signal,
  */
 
 int
-buflist_mouse_init ()
+buflist_mouse_init (void)
 {
     int i;
 
@@ -458,6 +458,6 @@ buflist_mouse_init ()
  */
 
 void
-buflist_mouse_end ()
+buflist_mouse_end (void)
 {
 }
diff --git a/src/plugins/buflist/buflist-mouse.h b/src/plugins/buflist/buflist-mouse.h
index 2503d5b3c..b25d5118f 100644
--- a/src/plugins/buflist/buflist-mouse.h
+++ b/src/plugins/buflist/buflist-mouse.h
@@ -22,7 +22,7 @@
 
 #define BUFLIST_MOUSE_HSIGNAL "buflist_mouse"
 
-extern int buflist_mouse_init ();
-extern void buflist_mouse_end ();
+extern int buflist_mouse_init (void);
+extern void buflist_mouse_end (void);
 
 #endif /* WEECHAT_PLUGIN_BUFLIST_MOUSE_H */
diff --git a/src/plugins/buflist/buflist.c b/src/plugins/buflist/buflist.c
index ba19faeaf..199af90cc 100644
--- a/src/plugins/buflist/buflist.c
+++ b/src/plugins/buflist/buflist.c
@@ -56,7 +56,7 @@ struct t_hdata *buflist_hdata_bar_window = NULL;
  */
 
 void
-buflist_add_bar ()
+buflist_add_bar (void)
 {
     weechat_bar_new (
         BUFLIST_BAR_NAME,
diff --git a/src/plugins/buflist/buflist.h b/src/plugins/buflist/buflist.h
index c8c2ece5a..2f9cc2f3b 100644
--- a/src/plugins/buflist/buflist.h
+++ b/src/plugins/buflist/buflist.h
@@ -37,7 +37,7 @@ extern struct t_hdata *buflist_hdata_bar;
 extern struct t_hdata *buflist_hdata_bar_item;
 extern struct t_hdata *buflist_hdata_bar_window;
 
-extern void buflist_add_bar ();
+extern void buflist_add_bar (void);
 extern void buflist_buffer_get_irc_pointers (struct t_gui_buffer *buffer,
                                              void **irc_server,
                                              void **irc_channel);
diff --git a/src/plugins/charset/charset.c b/src/plugins/charset/charset.c
index 580c33ebe..90827c86a 100644
--- a/src/plugins/charset/charset.c
+++ b/src/plugins/charset/charset.c
@@ -193,7 +193,7 @@ charset_config_create_option (const void *pointer, void *data,
  */
 
 int
-charset_config_init ()
+charset_config_init (void)
 {
     struct t_config_section *ptr_section;
 
@@ -281,7 +281,7 @@ charset_config_init ()
  */
 
 int
-charset_config_read ()
+charset_config_read (void)
 {
     return weechat_config_read (charset_config_file);
 }
@@ -291,7 +291,7 @@ charset_config_read ()
  */
 
 int
-charset_config_write ()
+charset_config_write (void)
 {
     return weechat_config_write (charset_config_file);
 }
@@ -465,7 +465,7 @@ charset_set (struct t_config_section *section, const char *type,
  */
 
 void
-charset_display_charsets ()
+charset_display_charsets (void)
 {
     weechat_printf (NULL,
                     _("%s: terminal: %s, internal: %s"),
diff --git a/src/plugins/exec/exec-buffer.c b/src/plugins/exec/exec-buffer.c
index d25d3c399..1226f020f 100644
--- a/src/plugins/exec/exec-buffer.c
+++ b/src/plugins/exec/exec-buffer.c
@@ -111,7 +111,7 @@ exec_buffer_close_cb (const void *pointer, void *data,
  */
 
 void
-exec_buffer_set_callbacks ()
+exec_buffer_set_callbacks (void)
 {
     struct t_infolist *ptr_infolist;
     struct t_gui_buffer *ptr_buffer;
diff --git a/src/plugins/exec/exec-buffer.h b/src/plugins/exec/exec-buffer.h
index a641d7b29..1d916a921 100644
--- a/src/plugins/exec/exec-buffer.h
+++ b/src/plugins/exec/exec-buffer.h
@@ -20,7 +20,7 @@
 #ifndef WEECHAT_PLUGIN_EXEC_BUFFER_H
 #define WEECHAT_PLUGIN_EXEC_BUFFER_H
 
-extern void exec_buffer_set_callbacks ();
+extern void exec_buffer_set_callbacks (void);
 extern struct t_gui_buffer *exec_buffer_new (const char *name,
                                              int free_content,
                                              int clear_buffer,
diff --git a/src/plugins/exec/exec-command.c b/src/plugins/exec/exec-command.c
index 6bb711681..58c1b6bf0 100644
--- a/src/plugins/exec/exec-command.c
+++ b/src/plugins/exec/exec-command.c
@@ -36,7 +36,7 @@
  */
 
 void
-exec_command_list ()
+exec_command_list (void)
 {
     struct t_exec_cmd *ptr_exec_cmd;
     char str_elapsed[32], str_time1[256], str_time2[256];
@@ -815,7 +815,7 @@ exec_command_exec (const void *pointer, void *data,
  */
 
 void
-exec_command_init ()
+exec_command_init (void)
 {
     weechat_hook_command (
         "exec",
diff --git a/src/plugins/exec/exec-command.h b/src/plugins/exec/exec-command.h
index ddc510d42..1ee947eea 100644
--- a/src/plugins/exec/exec-command.h
+++ b/src/plugins/exec/exec-command.h
@@ -47,6 +47,6 @@ struct t_exec_cmd_options
 extern int exec_command_run (struct t_gui_buffer *buffer,
                              int argc, char **argv, char **argv_eol,
                              int start_arg);
-extern void exec_command_init ();
+extern void exec_command_init (void);
 
 #endif /* WEECHAT_PLUGIN_EXEC_COMMAND_H */
diff --git a/src/plugins/exec/exec-completion.c b/src/plugins/exec/exec-completion.c
index 733cc1635..1090128e5 100644
--- a/src/plugins/exec/exec-completion.c
+++ b/src/plugins/exec/exec-completion.c
@@ -68,7 +68,7 @@ exec_completion_commands_ids_cb (const void *pointer, void *data,
  */
 
 void
-exec_completion_init ()
+exec_completion_init (void)
 {
     weechat_hook_completion ("exec_commands_ids",
                              N_("ids (numbers and names) of executed commands"),
diff --git a/src/plugins/exec/exec-completion.h b/src/plugins/exec/exec-completion.h
index 513c9d266..ca2bb3852 100644
--- a/src/plugins/exec/exec-completion.h
+++ b/src/plugins/exec/exec-completion.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_EXEC_COMPLETION_H
 #define WEECHAT_PLUGIN_EXEC_COMPLETION_H
 
-extern void exec_completion_init ();
+extern void exec_completion_init (void);
 
 #endif /* WEECHAT_PLUGIN_EXEC_COMPLETION_H */
diff --git a/src/plugins/exec/exec-config.c b/src/plugins/exec/exec-config.c
index 0ac5ce9a3..61b5e1366 100644
--- a/src/plugins/exec/exec-config.c
+++ b/src/plugins/exec/exec-config.c
@@ -99,7 +99,7 @@ exec_config_reload_cb (const void *pointer, void *data,
  */
 
 int
-exec_config_init ()
+exec_config_init (void)
 {
     exec_config_file = weechat_config_new (EXEC_CONFIG_PRIO_NAME,
                                            &exec_config_reload_cb, NULL, NULL);
@@ -181,7 +181,7 @@ exec_config_init ()
  */
 
 int
-exec_config_read ()
+exec_config_read (void)
 {
     return weechat_config_read (exec_config_file);
 }
@@ -191,7 +191,7 @@ exec_config_read ()
  */
 
 int
-exec_config_write ()
+exec_config_write (void)
 {
     return weechat_config_write (exec_config_file);
 }
@@ -201,7 +201,7 @@ exec_config_write ()
  */
 
 void
-exec_config_free ()
+exec_config_free (void)
 {
     weechat_config_free (exec_config_file);
     exec_config_file = NULL;
diff --git a/src/plugins/exec/exec-config.h b/src/plugins/exec/exec-config.h
index 39c323267..3deffb83a 100644
--- a/src/plugins/exec/exec-config.h
+++ b/src/plugins/exec/exec-config.h
@@ -35,9 +35,9 @@ extern struct t_config_option *exec_config_color_flag_running;
 extern char **exec_config_cmd_options;
 extern int exec_config_cmd_num_options;
 
-extern int exec_config_init ();
-extern int exec_config_read ();
-extern int exec_config_write ();
-extern void exec_config_free ();
+extern int exec_config_init (void);
+extern int exec_config_read (void);
+extern int exec_config_write (void);
+extern void exec_config_free (void);
 
 #endif /* WEECHAT_PLUGIN_EXEC_CONFIG_H */
diff --git a/src/plugins/exec/exec.c b/src/plugins/exec/exec.c
index 709bfe01f..96d0c9319 100644
--- a/src/plugins/exec/exec.c
+++ b/src/plugins/exec/exec.c
@@ -115,7 +115,7 @@ exec_search_by_id (const char *id)
  */
 
 struct t_exec_cmd *
-exec_add ()
+exec_add (void)
 {
     struct t_exec_cmd *new_exec_cmd;
     int i;
@@ -642,7 +642,7 @@ exec_free (struct t_exec_cmd *exec_cmd)
  */
 
 void
-exec_free_all ()
+exec_free_all (void)
 {
     while (exec_cmds)
     {
@@ -655,7 +655,7 @@ exec_free_all ()
  */
 
 void
-exec_print_log ()
+exec_print_log (void)
 {
     struct t_exec_cmd *ptr_exec_cmd;
 
diff --git a/src/plugins/exec/exec.h b/src/plugins/exec/exec.h
index 12d223243..d30e8c0bd 100644
--- a/src/plugins/exec/exec.h
+++ b/src/plugins/exec/exec.h
@@ -83,11 +83,11 @@ extern int exec_cmds_count;
 
 extern int exec_search_color (const char *color);
 extern struct t_exec_cmd *exec_search_by_id (const char *id);
-extern struct t_exec_cmd *exec_add ();
+extern struct t_exec_cmd *exec_add (void);
 extern int exec_process_cb (const void *pointer, void *data,
                             const char *command, int return_code,
                             const char *out, const char *err);
 extern void exec_free (struct t_exec_cmd *exec_cmd);
-extern void exec_free_all ();
+extern void exec_free_all (void);
 
 #endif /* WEECHAT_PLUGIN_EXEC_H */
diff --git a/src/plugins/fifo/fifo-command.c b/src/plugins/fifo/fifo-command.c
index 8649463ac..0826cdf4d 100644
--- a/src/plugins/fifo/fifo-command.c
+++ b/src/plugins/fifo/fifo-command.c
@@ -90,7 +90,7 @@ fifo_command_fifo (const void *pointer, void *data,
  */
 
 void
-fifo_command_init ()
+fifo_command_init (void)
 {
     weechat_hook_command (
         "fifo",
diff --git a/src/plugins/fifo/fifo-command.h b/src/plugins/fifo/fifo-command.h
index 3e8331288..d30725bfd 100644
--- a/src/plugins/fifo/fifo-command.h
+++ b/src/plugins/fifo/fifo-command.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_FIFO_COMMAND_H
 #define WEECHAT_PLUGIN_FIFO_COMMAND_H
 
-extern void fifo_command_init ();
+extern void fifo_command_init (void);
 
 #endif /* WEECHAT_PLUGIN_FIFO_COMMAND_H */
diff --git a/src/plugins/fifo/fifo-config.c b/src/plugins/fifo/fifo-config.c
index 7f95ad0f3..4b9c9be43 100644
--- a/src/plugins/fifo/fifo-config.c
+++ b/src/plugins/fifo/fifo-config.c
@@ -87,7 +87,7 @@ fifo_config_change_file_path (const void *pointer, void *data,
  */
 
 int
-fifo_config_init ()
+fifo_config_init (void)
 {
     fifo_config_file = weechat_config_new (FIFO_CONFIG_PRIO_NAME,
                                            NULL, NULL, NULL);
@@ -134,7 +134,7 @@ fifo_config_init ()
  */
 
 int
-fifo_config_read ()
+fifo_config_read (void)
 {
     return weechat_config_read (fifo_config_file);
 }
@@ -144,7 +144,7 @@ fifo_config_read ()
  */
 
 int
-fifo_config_write ()
+fifo_config_write (void)
 {
     return weechat_config_write (fifo_config_file);
 }
@@ -154,7 +154,7 @@ fifo_config_write ()
  */
 
 void
-fifo_config_free ()
+fifo_config_free (void)
 {
     weechat_config_free (fifo_config_file);
     fifo_config_file = NULL;
diff --git a/src/plugins/fifo/fifo-config.h b/src/plugins/fifo/fifo-config.h
index fcb2ac531..fd33fc561 100644
--- a/src/plugins/fifo/fifo-config.h
+++ b/src/plugins/fifo/fifo-config.h
@@ -26,9 +26,9 @@
 extern struct t_config_option *fifo_config_file_enabled;
 extern struct t_config_option *fifo_config_file_path;
 
-extern int fifo_config_init ();
-extern int fifo_config_read ();
-extern int fifo_config_write ();
-extern void fifo_config_free ();
+extern int fifo_config_init (void);
+extern int fifo_config_read (void);
+extern int fifo_config_write (void);
+extern void fifo_config_free (void);
 
 #endif /* WEECHAT_PLUGIN_FIFO_CONFIG_H */
diff --git a/src/plugins/fifo/fifo-info.c b/src/plugins/fifo/fifo-info.c
index 57f6dec6f..3f28fe67e 100644
--- a/src/plugins/fifo/fifo-info.c
+++ b/src/plugins/fifo/fifo-info.c
@@ -49,7 +49,7 @@ fifo_info_info_fifo_filename_cb (const void *pointer, void *data,
  */
 
 void
-fifo_info_init ()
+fifo_info_init (void)
 {
     weechat_hook_info ("fifo_filename", N_("name of FIFO pipe"), NULL,
                        &fifo_info_info_fifo_filename_cb, NULL, NULL);
diff --git a/src/plugins/fifo/fifo-info.h b/src/plugins/fifo/fifo-info.h
index fd2c8d2d5..04eb1abc7 100644
--- a/src/plugins/fifo/fifo-info.h
+++ b/src/plugins/fifo/fifo-info.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_FIFO_INFO_H
 #define WEECHAT_PLUGIN_FIFO_INFO_H
 
-extern void fifo_info_init ();
+extern void fifo_info_init (void);
 
 #endif /* WEECHAT_PLUGIN_FIFO_INFO_H */
diff --git a/src/plugins/fifo/fifo.c b/src/plugins/fifo/fifo.c
index 93d3a3eec..1df442748 100644
--- a/src/plugins/fifo/fifo.c
+++ b/src/plugins/fifo/fifo.c
@@ -62,7 +62,7 @@ int fifo_fd_cb (const void *pointer, void *data, int fd);
  */
 
 void
-fifo_create ()
+fifo_create (void)
 {
     struct stat st;
     struct t_hashtable *options;
@@ -146,7 +146,7 @@ fifo_create ()
  */
 
 void
-fifo_remove ()
+fifo_remove (void)
 {
     int fifo_found;
 
diff --git a/src/plugins/fifo/fifo.h b/src/plugins/fifo/fifo.h
index ba0a4a2fa..17237c9bf 100644
--- a/src/plugins/fifo/fifo.h
+++ b/src/plugins/fifo/fifo.h
@@ -29,7 +29,7 @@ extern int fifo_quiet;
 extern int fifo_fd;
 extern char *fifo_filename;
 
-extern void fifo_create ();
-extern void fifo_remove ();
+extern void fifo_create (void);
+extern void fifo_remove (void);
 
 #endif /* WEECHAT_PLUGIN_FIFO_H */
diff --git a/src/plugins/fset/fset-bar-item.c b/src/plugins/fset/fset-bar-item.c
index 32ab59ea4..207ca167a 100644
--- a/src/plugins/fset/fset-bar-item.c
+++ b/src/plugins/fset/fset-bar-item.c
@@ -39,7 +39,7 @@ struct t_gui_bar_item *fset_bar_item_fset = NULL;
  */
 
 void
-fset_bar_item_update ()
+fset_bar_item_update (void)
 {
     weechat_bar_item_update (FSET_BAR_ITEM_NAME);
 }
@@ -231,7 +231,7 @@ fset_bar_item_fset_cb (const void *pointer, void *data,
  */
 
 int
-fset_bar_item_init ()
+fset_bar_item_init (void)
 {
     fset_bar_item_fset = weechat_bar_item_new (
         FSET_BAR_ITEM_NAME,
@@ -245,7 +245,7 @@ fset_bar_item_init ()
  */
 
 void
-fset_bar_item_end ()
+fset_bar_item_end (void)
 {
     weechat_bar_item_remove (fset_bar_item_fset);
     fset_bar_item_fset = NULL;
diff --git a/src/plugins/fset/fset-bar-item.h b/src/plugins/fset/fset-bar-item.h
index d4162cc63..889f4ac21 100644
--- a/src/plugins/fset/fset-bar-item.h
+++ b/src/plugins/fset/fset-bar-item.h
@@ -22,8 +22,8 @@
 
 #define FSET_BAR_ITEM_NAME "fset"
 
-extern void fset_bar_item_update ();
-extern int fset_bar_item_init ();
-extern void fset_bar_item_end ();
+extern void fset_bar_item_update (void);
+extern int fset_bar_item_init (void);
+extern void fset_bar_item_end (void);
 
 #endif /* WEECHAT_PLUGIN_FSET_BAR_ITEM_H */
diff --git a/src/plugins/fset/fset-buffer.c b/src/plugins/fset/fset-buffer.c
index 74d586dc0..314ddd68e 100644
--- a/src/plugins/fset/fset-buffer.c
+++ b/src/plugins/fset/fset-buffer.c
@@ -42,7 +42,7 @@ struct t_hashtable *fset_buffer_hashtable_extra_vars = NULL;
  */
 
 void
-fset_buffer_set_title ()
+fset_buffer_set_title (void)
 {
     int num_options;
     char str_marked[32], str_title[8192];
@@ -1237,7 +1237,7 @@ fset_buffer_get_window_info (struct t_gui_window *window,
  */
 
 void
-fset_buffer_check_line_outside_window ()
+fset_buffer_check_line_outside_window (void)
 {
     struct t_gui_window *window;
     int start_line_y, chat_height, format_number, lines_per_option;
@@ -1477,7 +1477,7 @@ fset_buffer_close_cb (const void *pointer, void *data,
  */
 
 void
-fset_buffer_set_callbacks ()
+fset_buffer_set_callbacks (void)
 {
     struct t_gui_buffer *ptr_buffer;
 
@@ -1553,7 +1553,7 @@ fset_buffer_set_keys (struct t_hashtable *hashtable)
  */
 
 void
-fset_buffer_set_localvar_filter ()
+fset_buffer_set_localvar_filter (void)
 {
     if (!fset_buffer)
         return;
@@ -1567,7 +1567,7 @@ fset_buffer_set_localvar_filter ()
  */
 
 void
-fset_buffer_open ()
+fset_buffer_open (void)
 {
     struct t_hashtable *buffer_props;
 
@@ -1612,7 +1612,7 @@ fset_buffer_open ()
  */
 
 int
-fset_buffer_init ()
+fset_buffer_init (void)
 {
     fset_buffer_set_callbacks ();
 
@@ -1646,7 +1646,7 @@ fset_buffer_init ()
  */
 
 void
-fset_buffer_end ()
+fset_buffer_end (void)
 {
     if (fset_buffer)
     {
diff --git a/src/plugins/fset/fset-buffer.h b/src/plugins/fset/fset-buffer.h
index bb556b5d0..464b850b5 100644
--- a/src/plugins/fset/fset-buffer.h
+++ b/src/plugins/fset/fset-buffer.h
@@ -27,20 +27,20 @@ struct t_fset_option;
 extern struct t_gui_buffer *fset_buffer;
 extern int fset_buffer_selected_line;
 
-extern void fset_buffer_set_title ();
+extern void fset_buffer_set_title (void);
 extern int fset_buffer_display_option (struct t_fset_option *fset_option);
 extern void fset_buffer_refresh (int clear);
 extern void fset_buffer_set_current_line (int line);
-extern void fset_buffer_check_line_outside_window ();
+extern void fset_buffer_check_line_outside_window (void);
 extern int fset_buffer_window_scrolled_cb (const void *pointer,
                                            void *data,
                                            const char *signal,
                                            const char *type_data,
                                            void *signal_data);
 extern void fset_buffer_set_keys (struct t_hashtable *hashtable);
-extern void fset_buffer_set_localvar_filter ();
-extern void fset_buffer_open ();
-extern int fset_buffer_init ();
-extern void fset_buffer_end ();
+extern void fset_buffer_set_localvar_filter (void);
+extern void fset_buffer_open (void);
+extern int fset_buffer_init (void);
+extern void fset_buffer_end (void);
 
 #endif /* WEECHAT_PLUGIN_FSET_BUFFER_H */
diff --git a/src/plugins/fset/fset-command.c b/src/plugins/fset/fset-command.c
index 21f017956..74e179efd 100644
--- a/src/plugins/fset/fset-command.c
+++ b/src/plugins/fset/fset-command.c
@@ -638,7 +638,7 @@ fset_command_run_key_cb (const void *pointer, void *data,
  */
 
 void
-fset_command_init ()
+fset_command_init (void)
 {
     weechat_hook_command (
         "fset",
diff --git a/src/plugins/fset/fset-command.h b/src/plugins/fset/fset-command.h
index d0bc0f3e9..48cbd1e14 100644
--- a/src/plugins/fset/fset-command.h
+++ b/src/plugins/fset/fset-command.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_FSET_COMMAND_H
 #define WEECHAT_PLUGIN_FSET_COMMAND_H
 
-extern void fset_command_init ();
+extern void fset_command_init (void);
 
 #endif /* WEECHAT_PLUGIN_FSET_COMMAND_H */
diff --git a/src/plugins/fset/fset-completion.c b/src/plugins/fset/fset-completion.c
index c2bd6de53..b34692d75 100644
--- a/src/plugins/fset/fset-completion.c
+++ b/src/plugins/fset/fset-completion.c
@@ -115,7 +115,7 @@ fset_completion_option_cb (const void *pointer, void *data,
  */
 
 void
-fset_completion_init ()
+fset_completion_init (void)
 {
     weechat_hook_completion ("fset_options",
                              N_("configuration files, sections, options and "
diff --git a/src/plugins/fset/fset-completion.h b/src/plugins/fset/fset-completion.h
index d841c9a18..c9e9be1f2 100644
--- a/src/plugins/fset/fset-completion.h
+++ b/src/plugins/fset/fset-completion.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_FSET_COMPLETION_H
 #define WEECHAT_PLUGIN_FSET_COMPLETION_H
 
-extern void fset_completion_init ();
+extern void fset_completion_init (void);
 
 #endif /* WEECHAT_PLUGIN_FSET_COMPLETION_H */
diff --git a/src/plugins/fset/fset-config.c b/src/plugins/fset/fset-config.c
index 8b6bda1d0..3c3205f90 100644
--- a/src/plugins/fset/fset-config.c
+++ b/src/plugins/fset/fset-config.c
@@ -365,7 +365,7 @@ fset_config_change_title_color_cb (const void *pointer, void *data,
  */
 
 int
-fset_config_init ()
+fset_config_init (void)
 {
     fset_config_file = weechat_config_new (FSET_CONFIG_PRIO_NAME,
                                            &fset_config_reload, NULL, NULL);
@@ -1148,7 +1148,7 @@ fset_config_init ()
  */
 
 int
-fset_config_read ()
+fset_config_read (void)
 {
     int rc;
 
@@ -1169,7 +1169,7 @@ fset_config_read ()
  */
 
 int
-fset_config_write ()
+fset_config_write (void)
 {
     return weechat_config_write (fset_config_file);
 }
@@ -1179,7 +1179,7 @@ fset_config_write ()
  */
 
 void
-fset_config_free ()
+fset_config_free (void)
 {
     weechat_config_free (fset_config_file);
     fset_config_file = NULL;
diff --git a/src/plugins/fset/fset-config.h b/src/plugins/fset/fset-config.h
index 5fd350d59..5a283521b 100644
--- a/src/plugins/fset/fset-config.h
+++ b/src/plugins/fset/fset-config.h
@@ -88,9 +88,9 @@ extern char **fset_config_sort_fields;
 extern int fset_config_sort_fields_count;
 extern int fset_config_format_option_num_lines[2];
 
-extern int fset_config_init ();
-extern int fset_config_read ();
-extern int fset_config_write ();
-extern void fset_config_free ();
+extern int fset_config_init (void);
+extern int fset_config_read (void);
+extern int fset_config_write (void);
+extern void fset_config_free (void);
 
 #endif /* WEECHAT_PLUGIN_FSET_CONFIG_H */
diff --git a/src/plugins/fset/fset-info.c b/src/plugins/fset/fset-info.c
index 9ee715ec6..75ce14b0d 100644
--- a/src/plugins/fset/fset-info.c
+++ b/src/plugins/fset/fset-info.c
@@ -94,7 +94,7 @@ fset_info_infolist_fset_option_cb (const void *pointer, void *data,
  */
 
 void
-fset_info_init ()
+fset_info_init (void)
 {
     /* infolist hooks */
     weechat_hook_infolist (
diff --git a/src/plugins/fset/fset-info.h b/src/plugins/fset/fset-info.h
index 62ab14bc2..51d07c680 100644
--- a/src/plugins/fset/fset-info.h
+++ b/src/plugins/fset/fset-info.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_FSET_INFO_H
 #define WEECHAT_PLUGIN_FSET_INFO_H
 
-extern void fset_info_init ();
+extern void fset_info_init (void);
 
 #endif /* WEECHAT_PLUGIN_FSET_INFO_H */
diff --git a/src/plugins/fset/fset-mouse.c b/src/plugins/fset/fset-mouse.c
index 1e4123ccb..8afd7625f 100644
--- a/src/plugins/fset/fset-mouse.c
+++ b/src/plugins/fset/fset-mouse.c
@@ -311,7 +311,7 @@ fset_mouse_hsignal_cb (const void *pointer, void *data, const char *signal,
  */
 
 int
-fset_mouse_init ()
+fset_mouse_init (void)
 {
     struct t_hashtable *keys;
 
@@ -356,6 +356,6 @@ fset_mouse_init ()
  */
 
 void
-fset_mouse_end ()
+fset_mouse_end (void)
 {
 }
diff --git a/src/plugins/fset/fset-mouse.h b/src/plugins/fset/fset-mouse.h
index 71cf1ea07..84ea23cda 100644
--- a/src/plugins/fset/fset-mouse.h
+++ b/src/plugins/fset/fset-mouse.h
@@ -22,7 +22,7 @@
 
 #define FSET_MOUSE_HSIGNAL "fset_mouse"
 
-extern int fset_mouse_init ();
-extern void fset_mouse_end ();
+extern int fset_mouse_init (void);
+extern void fset_mouse_end (void);
 
 #endif /* WEECHAT_PLUGIN_FSET_MOUSE_H */
diff --git a/src/plugins/fset/fset-option.c b/src/plugins/fset/fset-option.c
index 4f2a74908..d53988a36 100644
--- a/src/plugins/fset/fset-option.c
+++ b/src/plugins/fset/fset-option.c
@@ -743,7 +743,7 @@ fset_option_init_max_length (struct t_fset_option_max_length *max_length)
  */
 
 void
-fset_option_set_max_length_fields_all ()
+fset_option_set_max_length_fields_all (void)
 {
     int i, num_options;
     struct t_fset_option *ptr_fset_option;
@@ -929,7 +929,7 @@ fset_option_free_cb (void *data, struct t_arraylist *arraylist, void *pointer)
  */
 
 struct t_arraylist *
-fset_option_get_arraylist_options ()
+fset_option_get_arraylist_options (void)
 {
     return weechat_arraylist_new (100, 1, 0,
                                   &fset_option_compare_options_cb, NULL,
@@ -941,7 +941,7 @@ fset_option_get_arraylist_options ()
  */
 
 struct t_fset_option_max_length *
-fset_option_get_max_length ()
+fset_option_get_max_length (void)
 {
     struct t_fset_option_max_length *max_length;
 
@@ -957,7 +957,7 @@ fset_option_get_max_length ()
  */
 
 void
-fset_option_get_options ()
+fset_option_get_options (void)
 {
     struct t_fset_option *new_fset_option, *ptr_fset_option;
     struct t_config_file *ptr_config;
@@ -1278,7 +1278,7 @@ fset_option_mark_options_matching_filter (const char *filter, int mark)
  */
 
 void
-fset_option_unmark_all ()
+fset_option_unmark_all (void)
 {
     int num_options, marked, set_title, i;
     struct t_fset_option *ptr_fset_option;
@@ -1772,7 +1772,7 @@ fset_option_add_to_infolist (struct t_infolist *infolist,
  */
 
 void
-fset_option_print_log ()
+fset_option_print_log (void)
 {
     struct t_fset_option *ptr_fset_option;
     int num_options, i;
@@ -1815,7 +1815,7 @@ fset_option_print_log ()
  */
 
 int
-fset_option_init ()
+fset_option_init (void)
 {
     fset_options = fset_option_get_arraylist_options ();
     if (!fset_options)
@@ -1891,7 +1891,7 @@ fset_option_init ()
  */
 
 void
-fset_option_end ()
+fset_option_end (void)
 {
     if (fset_options)
     {
diff --git a/src/plugins/fset/fset-option.h b/src/plugins/fset/fset-option.h
index 1e5b770e4..10cf62b7e 100644
--- a/src/plugins/fset/fset-option.h
+++ b/src/plugins/fset/fset-option.h
@@ -95,11 +95,11 @@ extern int fset_option_valid (struct t_fset_option *option);
 extern struct t_fset_option *fset_option_search_by_name (const char *name,
                                                          int *line);
 extern int fset_option_value_is_changed (struct t_fset_option *option);
-extern void fset_option_set_max_length_fields_all ();
+extern void fset_option_set_max_length_fields_all (void);
 extern void fset_option_free (struct t_fset_option *fset_option);
-extern struct t_arraylist *fset_option_get_arraylist_options ();
-extern struct t_fset_option_max_length *fset_option_get_max_length ();
-extern void fset_option_get_options ();
+extern struct t_arraylist *fset_option_get_arraylist_options (void);
+extern struct t_fset_option_max_length *fset_option_get_max_length (void);
+extern void fset_option_get_options (void);
 extern void fset_option_set_filter (const char *filter);
 extern void fset_option_filter_options (const char *filter);
 extern void fset_option_toggle_value (struct t_fset_option *fset_option,
@@ -119,7 +119,7 @@ extern void fset_option_toggle_mark (struct t_fset_option *fset_option,
                                      struct t_config_option *option);
 extern void fset_option_mark_options_matching_filter (const char *filter,
                                                       int mark);
-extern void fset_option_unmark_all ();
+extern void fset_option_unmark_all (void);
 extern int fset_option_export (const char *filename, int with_help);
 extern int fset_option_import (const char *filename);
 extern int fset_option_config_cb (const void *pointer,
@@ -131,8 +131,8 @@ extern struct t_hdata *fset_option_hdata_option_cb (const void *pointer,
                                                     const char *hdata_name);
 extern int fset_option_add_to_infolist (struct t_infolist *infolist,
                                         struct t_fset_option *option);
-extern void fset_option_print_log ();
-extern int fset_option_init ();
-extern void fset_option_end ();
+extern void fset_option_print_log (void);
+extern int fset_option_init (void);
+extern void fset_option_end (void);
 
 #endif /* WEECHAT_PLUGIN_FSET_OPTION_H */
diff --git a/src/plugins/fset/fset.c b/src/plugins/fset/fset.c
index 1bb34b5bd..7c5067cba 100644
--- a/src/plugins/fset/fset.c
+++ b/src/plugins/fset/fset.c
@@ -86,7 +86,7 @@ fset_debug_dump_cb (const void *pointer, void *data,
  */
 
 void
-fset_add_bar ()
+fset_add_bar (void)
 {
     weechat_bar_new (
         FSET_BAR_NAME, "off", "0", "window",
diff --git a/src/plugins/fset/fset.h b/src/plugins/fset/fset.h
index 53cf3a19d..08fd6adc9 100644
--- a/src/plugins/fset/fset.h
+++ b/src/plugins/fset/fset.h
@@ -33,6 +33,6 @@ extern struct t_hdata *fset_hdata_config_section;
 extern struct t_hdata *fset_hdata_config_option;
 extern struct t_hdata *fset_hdata_fset_option;
 
-extern void fset_add_bar ();
+extern void fset_add_bar (void);
 
 #endif /* WEECHAT_PLUGIN_FSET_H */
diff --git a/src/plugins/guile/weechat-guile-api.c b/src/plugins/guile/weechat-guile-api.c
index e2b0c19e2..f47ca9175 100644
--- a/src/plugins/guile/weechat-guile-api.c
+++ b/src/plugins/guile/weechat-guile-api.c
@@ -621,7 +621,7 @@ weechat_guile_api_mkdir_parents (SCM directory, SCM mode)
 }
 
 SCM
-weechat_guile_api_list_new ()
+weechat_guile_api_list_new (void)
 {
     const char *result;
     SCM return_value;
@@ -3541,7 +3541,7 @@ weechat_guile_api_unhook (SCM hook)
 }
 
 SCM
-weechat_guile_api_unhook_all ()
+weechat_guile_api_unhook_all (void)
 {
     API_INIT_FUNC(1, "unhook_all", API_RETURN_ERROR);
 
@@ -3707,7 +3707,7 @@ weechat_guile_api_buffer_search (SCM plugin, SCM name)
 }
 
 SCM
-weechat_guile_api_buffer_search_main ()
+weechat_guile_api_buffer_search_main (void)
 {
     const char *result;
     SCM return_value;
@@ -3720,7 +3720,7 @@ weechat_guile_api_buffer_search_main ()
 }
 
 SCM
-weechat_guile_api_current_buffer ()
+weechat_guile_api_current_buffer (void)
 {
     const char *result;
     SCM return_value;
@@ -3892,7 +3892,7 @@ weechat_guile_api_line_search_by_id (SCM buffer, SCM id)
 }
 
 SCM
-weechat_guile_api_current_window ()
+weechat_guile_api_current_window (void)
 {
     const char *result;
     SCM return_value;
@@ -4652,7 +4652,7 @@ weechat_guile_api_info_get_hashtable (SCM info_name, SCM hash)
 }
 
 SCM
-weechat_guile_api_infolist_new ()
+weechat_guile_api_infolist_new (void)
 {
     const char *result;
     SCM return_value;
diff --git a/src/plugins/guile/weechat-guile.c b/src/plugins/guile/weechat-guile.c
index 22900675e..64e024742 100644
--- a/src/plugins/guile/weechat-guile.c
+++ b/src/plugins/guile/weechat-guile.c
@@ -116,7 +116,7 @@ char *guile_action_autoload_list = NULL;
  */
 
 void
-weechat_guile_output_flush ()
+weechat_guile_output_flush (void)
 {
     const char *ptr_command;
     char *temp_buffer, *command;
@@ -684,7 +684,7 @@ weechat_guile_unload_name (const char *name)
  */
 
 void
-weechat_guile_unload_all ()
+weechat_guile_unload_all (void)
 {
     while (guile_scripts)
     {
diff --git a/src/plugins/irc/irc-bar-item.c b/src/plugins/irc/irc-bar-item.c
index 932c34224..ea3633d4a 100644
--- a/src/plugins/irc/irc-bar-item.c
+++ b/src/plugins/irc/irc-bar-item.c
@@ -704,7 +704,7 @@ irc_bar_item_buffer_switch (const void *pointer, void *data,
  */
 
 void
-irc_bar_item_update_channel ()
+irc_bar_item_update_channel (void)
 {
     weechat_bar_item_update ("buffer_name");
     weechat_bar_item_update ("buffer_short_name");
@@ -716,7 +716,7 @@ irc_bar_item_update_channel ()
  */
 
 void
-irc_bar_item_init ()
+irc_bar_item_init (void)
 {
     weechat_bar_item_new ("buffer_plugin",
                           &irc_bar_item_buffer_plugin, NULL, NULL);
diff --git a/src/plugins/irc/irc-bar-item.h b/src/plugins/irc/irc-bar-item.h
index 14c659ded..9cc48fae3 100644
--- a/src/plugins/irc/irc-bar-item.h
+++ b/src/plugins/irc/irc-bar-item.h
@@ -20,7 +20,7 @@
 #ifndef WEECHAT_PLUGIN_IRC_BAR_ITEM_H
 #define WEECHAT_PLUGIN_IRC_BAR_ITEM_H
 
-extern void irc_bar_item_update_channel ();
-extern void irc_bar_item_init ();
+extern void irc_bar_item_update_channel (void);
+extern void irc_bar_item_init (void);
 
 #endif /* WEECHAT_PLUGIN_IRC_BAR_ITEM_H */
diff --git a/src/plugins/irc/irc-buffer.c b/src/plugins/irc/irc-buffer.c
index 2977ebd2c..12373e18d 100644
--- a/src/plugins/irc/irc-buffer.c
+++ b/src/plugins/irc/irc-buffer.c
@@ -305,7 +305,7 @@ irc_buffer_nickcmp_cb (const void *pointer, void *data,
  */
 
 struct t_gui_buffer *
-irc_buffer_search_server_lowest_number ()
+irc_buffer_search_server_lowest_number (void)
 {
     struct t_gui_buffer *ptr_buffer;
     struct t_irc_server *ptr_server;
diff --git a/src/plugins/irc/irc-buffer.h b/src/plugins/irc/irc-buffer.h
index 4d46e6819..8c90cde61 100644
--- a/src/plugins/irc/irc-buffer.h
+++ b/src/plugins/irc/irc-buffer.h
@@ -52,7 +52,7 @@ extern int irc_buffer_close_cb (const void *pointer, void *data,
 extern int irc_buffer_nickcmp_cb (const void *pointer, void *data,
                                   struct t_gui_buffer *buffer,
                                   const char *nick1, const char *nick2);
-extern struct t_gui_buffer *irc_buffer_search_server_lowest_number ();
+extern struct t_gui_buffer *irc_buffer_search_server_lowest_number (void);
 extern struct t_gui_buffer *irc_buffer_search_private_lowest_number (struct t_irc_server *server);
 extern void irc_buffer_move_near_server (struct t_irc_server *server,
                                          int list_buffer, int channel_type,
diff --git a/src/plugins/irc/irc-color.c b/src/plugins/irc/irc-color.c
index 23bffd1fd..6ab50064f 100644
--- a/src/plugins/irc/irc-color.c
+++ b/src/plugins/irc/irc-color.c
@@ -1080,7 +1080,7 @@ irc_color_weechat_add_to_infolist (struct t_infolist *infolist)
  */
 
 void
-irc_color_init ()
+irc_color_init (void)
 {
     irc_color_index_string_decoded = 0;
     memset (irc_color_string_decoded, 0, sizeof (irc_color_string_decoded));
@@ -1091,7 +1091,7 @@ irc_color_init ()
  */
 
 void
-irc_color_end ()
+irc_color_end (void)
 {
     int i;
 
diff --git a/src/plugins/irc/irc-color.h b/src/plugins/irc/irc-color.h
index c410eda00..5e1c7b468 100644
--- a/src/plugins/irc/irc-color.h
+++ b/src/plugins/irc/irc-color.h
@@ -127,7 +127,7 @@ extern char *irc_color_modifier_cb (const void *pointer, void *data,
                                     const char *string);
 extern char *irc_color_for_tags (const char *color);
 extern int irc_color_weechat_add_to_infolist (struct t_infolist *infolist);
-extern void irc_color_init ();
-extern void irc_color_end ();
+extern void irc_color_init (void);
+extern void irc_color_end (void);
 
 #endif /* WEECHAT_PLUGIN_IRC_COLOR_H */
diff --git a/src/plugins/irc/irc-command.c b/src/plugins/irc/irc-command.c
index e57f07dd4..13ac13490 100644
--- a/src/plugins/irc/irc-command.c
+++ b/src/plugins/irc/irc-command.c
@@ -7036,7 +7036,7 @@ IRC_COMMAND_CALLBACK(whowas)
  */
 
 void
-irc_command_init ()
+irc_command_init (void)
 {
     struct t_hook *ptr_hook;
 
diff --git a/src/plugins/irc/irc-command.h b/src/plugins/irc/irc-command.h
index 35c40d4cd..c3319ca25 100644
--- a/src/plugins/irc/irc-command.h
+++ b/src/plugins/irc/irc-command.h
@@ -85,6 +85,6 @@ extern void irc_command_part_channel (struct t_irc_server *server,
                                       const char *part_message);
 extern void irc_command_quit_server (struct t_irc_server *server,
                                      const char *arguments);
-extern void irc_command_init ();
+extern void irc_command_init (void);
 
 #endif /* WEECHAT_PLUGIN_IRC_COMMAND_H */
diff --git a/src/plugins/irc/irc-completion.c b/src/plugins/irc/irc-completion.c
index 6176fd4b3..25ec7c820 100644
--- a/src/plugins/irc/irc-completion.c
+++ b/src/plugins/irc/irc-completion.c
@@ -956,7 +956,7 @@ irc_completion_raw_filters_cb (const void *pointer, void *data,
  */
 
 void
-irc_completion_init ()
+irc_completion_init (void)
 {
     weechat_hook_completion ("irc_server",
                              N_("current IRC server"),
diff --git a/src/plugins/irc/irc-completion.h b/src/plugins/irc/irc-completion.h
index 8bc63b6f2..6dbdd238c 100644
--- a/src/plugins/irc/irc-completion.h
+++ b/src/plugins/irc/irc-completion.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_IRC_COMPLETION_H
 #define WEECHAT_PLUGIN_IRC_COMPLETION_H
 
-extern void irc_completion_init ();
+extern void irc_completion_init (void);
 
 #endif /* WEECHAT_PLUGIN_IRC_COMPLETION_H */
diff --git a/src/plugins/irc/irc-config.c b/src/plugins/irc/irc-config.c
index a2f0fb337..4a5492336 100644
--- a/src/plugins/irc/irc-config.c
+++ b/src/plugins/irc/irc-config.c
@@ -228,7 +228,7 @@ irc_config_get_server_from_option_name (const char *name)
  */
 
 void
-irc_config_compute_nick_colors ()
+irc_config_compute_nick_colors (void)
 {
     struct t_irc_server *ptr_server;
     struct t_irc_channel *ptr_channel;
@@ -3174,7 +3174,7 @@ irc_config_update_cb (const void *pointer, void *data,
  */
 
 int
-irc_config_init ()
+irc_config_init (void)
 {
     int i;
 
@@ -4249,7 +4249,7 @@ irc_config_init ()
  */
 
 int
-irc_config_read ()
+irc_config_read (void)
 {
     int rc;
 
@@ -4289,7 +4289,7 @@ irc_config_write (int write_temp_servers)
  */
 
 void
-irc_config_free ()
+irc_config_free (void)
 {
     weechat_config_free (irc_config_file);
     irc_config_file = NULL;
diff --git a/src/plugins/irc/irc-config.h b/src/plugins/irc/irc-config.h
index 5d488544b..78555f039 100644
--- a/src/plugins/irc/irc-config.h
+++ b/src/plugins/irc/irc-config.h
@@ -244,9 +244,9 @@ struct t_config_option *irc_config_server_new_option (struct t_config_file *conf
                                                                               struct t_config_option *option),
                                                       const void *callback_change_pointer,
                                                       void *callback_change_data);
-extern int irc_config_init ();
-extern int irc_config_read ();
+extern int irc_config_init (void);
+extern int irc_config_read (void);
 extern int irc_config_write (int write_temp_servers);
-extern void irc_config_free ();
+extern void irc_config_free (void);
 
 #endif /* WEECHAT_PLUGIN_IRC_CONFIG_H */
diff --git a/src/plugins/irc/irc-debug.c b/src/plugins/irc/irc-debug.c
index 07bbc25a5..1f17e6ac8 100644
--- a/src/plugins/irc/irc-debug.c
+++ b/src/plugins/irc/irc-debug.c
@@ -68,7 +68,7 @@ irc_debug_signal_debug_dump_cb (const void *pointer, void *data,
  */
 
 void
-irc_debug_init ()
+irc_debug_init (void)
 {
     weechat_hook_signal ("debug_dump",
                          &irc_debug_signal_debug_dump_cb, NULL, NULL);
diff --git a/src/plugins/irc/irc-debug.h b/src/plugins/irc/irc-debug.h
index c7d793e8d..037df3885 100644
--- a/src/plugins/irc/irc-debug.h
+++ b/src/plugins/irc/irc-debug.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_IRC_DEBUG_H
 #define WEECHAT_PLUGIN_IRC_DEBUG_H
 
-extern void irc_debug_init ();
+extern void irc_debug_init (void);
 
 #endif /* WEECHAT_PLUGIN_IRC_DEBUG_H */
diff --git a/src/plugins/irc/irc-ignore.c b/src/plugins/irc/irc-ignore.c
index a2ca46783..77a805305 100644
--- a/src/plugins/irc/irc-ignore.c
+++ b/src/plugins/irc/irc-ignore.c
@@ -339,7 +339,7 @@ irc_ignore_free (struct t_irc_ignore *ignore)
  */
 
 void
-irc_ignore_free_all ()
+irc_ignore_free_all (void)
 {
     while (irc_ignore_list)
     {
@@ -414,7 +414,7 @@ irc_ignore_add_to_infolist (struct t_infolist *infolist,
  */
 
 void
-irc_ignore_print_log ()
+irc_ignore_print_log (void)
 {
     struct t_irc_ignore *ptr_ignore;
 
diff --git a/src/plugins/irc/irc-ignore.h b/src/plugins/irc/irc-ignore.h
index 405ddc29a..763a8fe7a 100644
--- a/src/plugins/irc/irc-ignore.h
+++ b/src/plugins/irc/irc-ignore.h
@@ -59,12 +59,12 @@ extern int irc_ignore_check (struct t_irc_server *server,
                              const char *channel, const char *nick,
                              const char *host);
 extern void irc_ignore_free (struct t_irc_ignore *ignore);
-extern void irc_ignore_free_all ();
+extern void irc_ignore_free_all (void);
 extern struct t_hdata *irc_ignore_hdata_ignore_cb (const void *pointer,
                                                    void *data,
                                                    const char *hdata_name);
 extern int irc_ignore_add_to_infolist (struct t_infolist *infolist,
                                        struct t_irc_ignore *ignore);
-extern void irc_ignore_print_log ();
+extern void irc_ignore_print_log (void);
 
 #endif /* WEECHAT_PLUGIN_IRC_IGNORE_H */
diff --git a/src/plugins/irc/irc-info.c b/src/plugins/irc/irc-info.c
index 16d675eeb..d778278c0 100644
--- a/src/plugins/irc/irc-info.c
+++ b/src/plugins/irc/irc-info.c
@@ -1335,7 +1335,7 @@ irc_info_infolist_irc_color_weechat_cb (const void *pointer, void *data,
  */
 
 void
-irc_info_init ()
+irc_info_init (void)
 {
     /* info hooks */
     weechat_hook_info (
diff --git a/src/plugins/irc/irc-info.h b/src/plugins/irc/irc-info.h
index 19fe39955..0d3c7f62e 100644
--- a/src/plugins/irc/irc-info.h
+++ b/src/plugins/irc/irc-info.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_IRC_INFO_H
 #define WEECHAT_PLUGIN_IRC_INFO_H
 
-extern void irc_info_init ();
+extern void irc_info_init (void);
 
 #endif /* WEECHAT_PLUGIN_IRC_INFO_H */
diff --git a/src/plugins/irc/irc-list.c b/src/plugins/irc/irc-list.c
index 65d5f98b1..0d1601367 100644
--- a/src/plugins/irc/irc-list.c
+++ b/src/plugins/irc/irc-list.c
@@ -1167,7 +1167,7 @@ irc_list_reset (struct t_irc_server *server)
  */
 
 struct t_irc_list *
-irc_list_alloc ()
+irc_list_alloc (void)
 {
     struct t_irc_list *list;
 
@@ -1348,7 +1348,7 @@ irc_list_mouse_hsignal_cb (const void *pointer, void *data, const char *signal,
  */
 
 void
-irc_list_init ()
+irc_list_init (void)
 {
     struct t_hashtable *keys;
 
@@ -1409,7 +1409,7 @@ irc_list_init ()
  */
 
 void
-irc_list_end ()
+irc_list_end (void)
 {
     if (irc_list_filter_hashtable_pointers)
     {
diff --git a/src/plugins/irc/irc-list.h b/src/plugins/irc/irc-list.h
index 308275039..6f8c0b4e0 100644
--- a/src/plugins/irc/irc-list.h
+++ b/src/plugins/irc/irc-list.h
@@ -69,7 +69,7 @@ extern int irc_list_hsignal_redirect_list_cb (const void *pointer,
                                               struct t_hashtable *hashtable);
 extern int irc_list_export (struct t_irc_server *server, const char *filename);
 extern void irc_list_reset (struct t_irc_server *server);
-extern struct t_irc_list *irc_list_alloc ();
+extern struct t_irc_list *irc_list_alloc (void);
 extern void irc_list_free_data (struct t_irc_server *server);
 extern void irc_list_free (struct t_irc_server *server);
 extern struct t_hdata *irc_list_hdata_list_channel_cb (const void *pointer,
@@ -77,7 +77,7 @@ extern struct t_hdata *irc_list_hdata_list_channel_cb (const void *pointer,
                                                        const char *hdata_name);
 extern struct t_hdata *irc_list_hdata_list_cb (const void *pointer, void *data,
                                                const char *hdata_name);
-extern void irc_list_init ();
-extern void irc_list_end ();
+extern void irc_list_init (void);
+extern void irc_list_end (void);
 
 #endif /* WEECHAT_PLUGIN_IRC_LIST_H */
diff --git a/src/plugins/irc/irc-nick.c b/src/plugins/irc/irc-nick.c
index c95dcef6d..50bc2788e 100644
--- a/src/plugins/irc/irc-nick.c
+++ b/src/plugins/irc/irc-nick.c
@@ -465,7 +465,7 @@ irc_nick_nicklist_set (struct t_irc_channel *channel,
  */
 
 void
-irc_nick_nicklist_set_prefix_color_all ()
+irc_nick_nicklist_set_prefix_color_all (void)
 {
     struct t_irc_server *ptr_server;
     struct t_irc_channel *ptr_channel;
@@ -493,7 +493,7 @@ irc_nick_nicklist_set_prefix_color_all ()
  */
 
 void
-irc_nick_nicklist_set_color_all ()
+irc_nick_nicklist_set_color_all (void)
 {
     struct t_irc_server *ptr_server;
     struct t_irc_channel *ptr_channel;
diff --git a/src/plugins/irc/irc-nick.h b/src/plugins/irc/irc-nick.h
index 0e3345db8..f45d68edf 100644
--- a/src/plugins/irc/irc-nick.h
+++ b/src/plugins/irc/irc-nick.h
@@ -59,8 +59,8 @@ extern int irc_nick_has_prefix_mode (struct t_irc_server *server,
                                      char prefix_mode);
 extern const char *irc_nick_get_prefix_color_name (struct t_irc_server *server,
                                                    char prefix);
-extern void irc_nick_nicklist_set_prefix_color_all ();
-extern void irc_nick_nicklist_set_color_all ();
+extern void irc_nick_nicklist_set_prefix_color_all (void);
+extern void irc_nick_nicklist_set_color_all (void);
 extern struct t_irc_nick *irc_nick_new_in_channel (struct t_irc_server *server,
                                                    struct t_irc_channel *channel,
                                                    const char *nickname,
diff --git a/src/plugins/irc/irc-notify.c b/src/plugins/irc/irc-notify.c
index f986c53c2..9c70b8683 100644
--- a/src/plugins/irc/irc-notify.c
+++ b/src/plugins/irc/irc-notify.c
@@ -409,7 +409,7 @@ irc_notify_new_for_server (struct t_irc_server *server)
  */
 
 void
-irc_notify_new_for_all_servers ()
+irc_notify_new_for_all_servers (void)
 {
     struct t_irc_server *ptr_server;
 
@@ -1231,7 +1231,7 @@ irc_notify_print_log (struct t_irc_server *server)
  */
 
 void
-irc_notify_hook_timer_ison ()
+irc_notify_hook_timer_ison (void)
 {
     weechat_unhook (irc_notify_timer_ison);
     irc_notify_timer_ison = weechat_hook_timer (
@@ -1244,7 +1244,7 @@ irc_notify_hook_timer_ison ()
  */
 
 void
-irc_notify_hook_timer_whois ()
+irc_notify_hook_timer_whois (void)
 {
     weechat_unhook (irc_notify_timer_whois);
     irc_notify_timer_whois = weechat_hook_timer (
@@ -1257,7 +1257,7 @@ irc_notify_hook_timer_whois ()
  */
 
 void
-irc_notify_init ()
+irc_notify_init (void)
 {
     irc_notify_hook_timer_ison ();
     irc_notify_hook_timer_whois ();
@@ -1272,7 +1272,7 @@ irc_notify_init ()
  */
 
 void
-irc_notify_end ()
+irc_notify_end (void)
 {
     if (irc_notify_timer_ison)
     {
diff --git a/src/plugins/irc/irc-notify.h b/src/plugins/irc/irc-notify.h
index 32dd65fd6..620b34d6a 100644
--- a/src/plugins/irc/irc-notify.h
+++ b/src/plugins/irc/irc-notify.h
@@ -52,7 +52,7 @@ extern struct t_irc_notify *irc_notify_new (struct t_irc_server *server,
                                             int check_away);
 extern void irc_notify_check_now (struct t_irc_notify *notify);
 extern void irc_notify_new_for_server (struct t_irc_server *server);
-extern void irc_notify_new_for_all_servers ();
+extern void irc_notify_new_for_all_servers (void);
 extern void irc_notify_free (struct t_irc_server *server,
                              struct t_irc_notify *notify, int remove_monitor);
 extern void irc_notify_display_is_on (struct t_irc_server *server,
@@ -75,9 +75,9 @@ extern struct t_hdata *irc_notify_hdata_notify_cb (const void *pointer,
 extern int irc_notify_add_to_infolist (struct t_infolist *infolist,
                                        struct t_irc_notify *notify);
 extern void irc_notify_print_log (struct t_irc_server *server);
-extern void irc_notify_hook_timer_ison ();
-extern void irc_notify_hook_timer_whois ();
-extern void irc_notify_init ();
-extern void irc_notify_end ();
+extern void irc_notify_hook_timer_ison (void);
+extern void irc_notify_hook_timer_whois (void);
+extern void irc_notify_init (void);
+extern void irc_notify_end (void);
 
 #endif /* WEECHAT_PLUGIN_IRC_NOTIFY_H */
diff --git a/src/plugins/irc/irc-raw.c b/src/plugins/irc/irc-raw.c
index fc7fce3d1..439121845 100644
--- a/src/plugins/irc/irc-raw.c
+++ b/src/plugins/irc/irc-raw.c
@@ -315,7 +315,7 @@ irc_raw_message_print (struct t_irc_raw_message *raw_message)
  */
 
 void
-irc_raw_set_localvar_filter ()
+irc_raw_set_localvar_filter (void)
 {
     if (!irc_raw_buffer)
         return;
@@ -329,7 +329,7 @@ irc_raw_set_localvar_filter ()
  */
 
 void
-irc_raw_set_title ()
+irc_raw_set_title (void)
 {
     char str_title[1024];
 
@@ -490,7 +490,7 @@ irc_raw_message_free (struct t_irc_raw_message *raw_message)
  */
 
 void
-irc_raw_message_free_all ()
+irc_raw_message_free_all (void)
 {
     while (irc_raw_messages)
     {
@@ -503,7 +503,7 @@ irc_raw_message_free_all ()
  */
 
 void
-irc_raw_message_remove_old ()
+irc_raw_message_remove_old (void)
 {
     int max_messages;
 
@@ -643,7 +643,7 @@ irc_raw_add_to_infolist (struct t_infolist *infolist,
  */
 
 void
-irc_raw_init ()
+irc_raw_init (void)
 {
     irc_raw_filter_hashtable_options = weechat_hashtable_new (
         8,
@@ -662,7 +662,7 @@ irc_raw_init ()
  */
 
 void
-irc_raw_end ()
+irc_raw_end (void)
 {
     irc_raw_message_free_all ();
 
diff --git a/src/plugins/irc/irc-raw.h b/src/plugins/irc/irc-raw.h
index b131ce40e..8758fdb89 100644
--- a/src/plugins/irc/irc-raw.h
+++ b/src/plugins/irc/irc-raw.h
@@ -68,7 +68,7 @@ extern void irc_raw_print (struct t_irc_server *server, int flags,
                            const char *message);
 extern int irc_raw_add_to_infolist (struct t_infolist *infolist,
                                     struct t_irc_raw_message *raw_message);
-extern void irc_raw_init ();
-extern void irc_raw_end ();
+extern void irc_raw_init (void);
+extern void irc_raw_end (void);
 
 #endif /* WEECHAT_PLUGIN_IRC_RAW_H */
diff --git a/src/plugins/irc/irc-redirect.c b/src/plugins/irc/irc-redirect.c
index 4fe6233e6..c25125b06 100644
--- a/src/plugins/irc/irc-redirect.c
+++ b/src/plugins/irc/irc-redirect.c
@@ -377,7 +377,7 @@ irc_redirect_pattern_free (struct t_irc_redirect_pattern *redirect_pattern)
  */
 
 void
-irc_redirect_pattern_free_all ()
+irc_redirect_pattern_free_all (void)
 {
     while (irc_redirect_patterns)
     {
@@ -1177,7 +1177,7 @@ irc_redirect_add_to_infolist (struct t_infolist *infolist,
  */
 
 void
-irc_redirect_pattern_print_log ()
+irc_redirect_pattern_print_log (void)
 {
     struct t_irc_redirect_pattern *ptr_redirect_pattern;
 
@@ -1391,7 +1391,7 @@ irc_redirect_command_hsignal_cb (const void *pointer, void *data,
  */
 
 void
-irc_redirect_init ()
+irc_redirect_init (void)
 {
     int i;
 
@@ -1411,7 +1411,7 @@ irc_redirect_init ()
  */
 
 void
-irc_redirect_end ()
+irc_redirect_end (void)
 {
     irc_redirect_pattern_free_all ();
 }
diff --git a/src/plugins/irc/irc-redirect.h b/src/plugins/irc/irc-redirect.h
index de35f25d6..b6b3fad5c 100644
--- a/src/plugins/irc/irc-redirect.h
+++ b/src/plugins/irc/irc-redirect.h
@@ -121,7 +121,7 @@ extern int irc_redirect_pattern_add_to_infolist (struct t_infolist *infolist,
                                                  struct t_irc_redirect_pattern *redirect_pattern);
 extern int irc_redirect_add_to_infolist (struct t_infolist *infolist,
                                          struct t_irc_redirect *redirect);
-extern void irc_redirect_pattern_print_log ();
+extern void irc_redirect_pattern_print_log (void);
 extern void irc_redirect_print_log (struct t_irc_server *server);
 extern int irc_redirect_pattern_hsignal_cb (const void *pointer, void *data,
                                             const char *signal,
@@ -129,7 +129,7 @@ extern int irc_redirect_pattern_hsignal_cb (const void *pointer, void *data,
 extern int irc_redirect_command_hsignal_cb (const void *pointer, void *data,
                                             const char *signal,
                                             struct t_hashtable *hashtable);
-extern void irc_redirect_init ();
-extern void irc_redirect_end ();
+extern void irc_redirect_init (void);
+extern void irc_redirect_end (void);
 
 #endif /* WEECHAT_PLUGIN_IRC_REDIRECT_H */
diff --git a/src/plugins/irc/irc-server.c b/src/plugins/irc/irc-server.c
index c06e1f9ca..e9ff96bc1 100644
--- a/src/plugins/irc/irc-server.c
+++ b/src/plugins/irc/irc-server.c
@@ -2422,7 +2422,7 @@ irc_server_free (struct t_irc_server *server)
  */
 
 void
-irc_server_free_all ()
+irc_server_free_all (void)
 {
     /* for each server in memory, remove it */
     while (irc_servers)
@@ -3480,7 +3480,7 @@ irc_server_msgq_add_buffer (struct t_irc_server *server, const char *buffer)
  */
 
 void
-irc_server_msgq_flush ()
+irc_server_msgq_flush (void)
 {
     struct t_irc_message *next;
     char *ptr_data, *new_msg, *new_msg2, *ptr_msg, *ptr_msg2, *pos;
@@ -4849,7 +4849,7 @@ irc_server_create_buffer (struct t_irc_server *server)
  */
 
 char *
-irc_server_fingerprint_str_sizes ()
+irc_server_fingerprint_str_sizes (void)
 {
     char str_sizes[1024], str_one_size[128];
     int i;
@@ -5819,7 +5819,7 @@ irc_server_disconnect (struct t_irc_server *server, int switch_address,
  */
 
 void
-irc_server_disconnect_all ()
+irc_server_disconnect_all (void)
 {
     struct t_irc_server *ptr_server;
 
@@ -6948,7 +6948,7 @@ irc_server_add_to_infolist (struct t_infolist *infolist,
  */
 
 void
-irc_server_print_log ()
+irc_server_print_log (void)
 {
     struct t_irc_server *ptr_server;
     struct t_irc_channel *ptr_channel;
diff --git a/src/plugins/irc/irc-server.h b/src/plugins/irc/irc-server.h
index 038084188..a3e755f3e 100644
--- a/src/plugins/irc/irc-server.h
+++ b/src/plugins/irc/irc-server.h
@@ -400,7 +400,7 @@ extern struct t_irc_server *irc_server_alloc (const char *name);
 extern struct t_irc_server *irc_server_alloc_with_url (const char *irc_url);
 extern void irc_server_apply_command_line_options (struct t_irc_server *server,
                                                    int argc, char **argv);
-extern void irc_server_free_all ();
+extern void irc_server_free_all (void);
 extern struct t_irc_server *irc_server_copy (struct t_irc_server *server,
                                              const char *new_name);
 extern int irc_server_rename (struct t_irc_server *server, const char *new_name);
@@ -418,10 +418,10 @@ extern struct t_arraylist *irc_server_sendf (struct t_irc_server *server,
                                              const char *format, ...);
 extern void irc_server_msgq_add_buffer (struct t_irc_server *server,
                                         const char *buffer);
-extern void irc_server_msgq_flush ();
+extern void irc_server_msgq_flush (void);
 extern void irc_server_set_buffer_title (struct t_irc_server *server);
 extern struct t_gui_buffer *irc_server_create_buffer (struct t_irc_server *server);
-char *irc_server_fingerprint_str_sizes ();
+char *irc_server_fingerprint_str_sizes (void);
 extern int irc_server_connect (struct t_irc_server *server);
 extern void irc_server_auto_connect (int auto_connect);
 extern void irc_server_autojoin_channels (struct t_irc_server *server);
@@ -442,7 +442,7 @@ extern void irc_server_switch_address (struct t_irc_server *server,
                                        int connection);
 extern void irc_server_disconnect (struct t_irc_server *server,
                                    int switch_address, int reconnect);
-extern void irc_server_disconnect_all ();
+extern void irc_server_disconnect_all (void);
 extern void irc_server_execute_command (struct t_irc_server *server);
 extern void irc_server_free_sasl_data (struct t_irc_server *server);
 extern void irc_server_free (struct t_irc_server *server);
@@ -465,6 +465,6 @@ extern struct t_hdata *irc_server_hdata_server_cb (const void *pointer,
 extern int irc_server_add_to_infolist (struct t_infolist *infolist,
                                        struct t_irc_server *server,
                                        int force_disconnected_state);
-extern void irc_server_print_log ();
+extern void irc_server_print_log (void);
 
 #endif /* WEECHAT_PLUGIN_IRC_SERVER_H */
diff --git a/src/plugins/irc/irc-upgrade.c b/src/plugins/irc/irc-upgrade.c
index f0d3d4b83..12b83b6ca 100644
--- a/src/plugins/irc/irc-upgrade.c
+++ b/src/plugins/irc/irc-upgrade.c
@@ -293,7 +293,7 @@ irc_upgrade_save (int force_disconnected_state)
  */
 
 void
-irc_upgrade_set_buffer_callbacks ()
+irc_upgrade_set_buffer_callbacks (void)
 {
     struct t_infolist *infolist;
     struct t_gui_buffer *ptr_buffer;
@@ -990,7 +990,7 @@ irc_upgrade_read_cb (const void *pointer, void *data,
  */
 
 void
-irc_upgrade_set_buffer_properties ()
+irc_upgrade_set_buffer_properties (void)
 {
     struct t_irc_server *ptr_server;
     struct t_irc_channel *ptr_channel;
@@ -1021,7 +1021,7 @@ irc_upgrade_set_buffer_properties ()
  */
 
 int
-irc_upgrade_load ()
+irc_upgrade_load (void)
 {
     int rc;
     struct t_upgrade_file *upgrade_file;
diff --git a/src/plugins/irc/irc-upgrade.h b/src/plugins/irc/irc-upgrade.h
index 6a1093204..3aba9cd01 100644
--- a/src/plugins/irc/irc-upgrade.h
+++ b/src/plugins/irc/irc-upgrade.h
@@ -40,6 +40,6 @@ enum t_irc_upgrade_type
 extern int irc_upgrading;
 
 extern int irc_upgrade_save (int force_disconnected_state);
-extern int irc_upgrade_load ();
+extern int irc_upgrade_load (void);
 
 #endif /* WEECHAT_PLUGIN_IRC_UPGRADE_H */
diff --git a/src/plugins/logger/logger-buffer.c b/src/plugins/logger/logger-buffer.c
index c86fb9c69..df0ffbcc2 100644
--- a/src/plugins/logger/logger-buffer.c
+++ b/src/plugins/logger/logger-buffer.c
@@ -767,7 +767,7 @@ logger_buffer_start_all (int write_info_line)
  */
 
 void
-logger_buffer_flush ()
+logger_buffer_flush (void)
 {
     struct t_logger_buffer *ptr_logger_buffer;
 
@@ -800,7 +800,7 @@ logger_buffer_flush ()
  */
 
 void
-logger_buffer_adjust_log_filenames ()
+logger_buffer_adjust_log_filenames (void)
 {
     struct t_infolist *ptr_infolist;
     struct t_logger_buffer *ptr_logger_buffer;
diff --git a/src/plugins/logger/logger-buffer.h b/src/plugins/logger/logger-buffer.h
index c494e7c5e..ec4da52af 100644
--- a/src/plugins/logger/logger-buffer.h
+++ b/src/plugins/logger/logger-buffer.h
@@ -73,8 +73,8 @@ extern void logger_buffer_stop (struct t_logger_buffer *logger_buffer,
 extern void logger_buffer_stop_all (int write_info_line);
 extern void logger_buffer_start (struct t_gui_buffer *buffer, int write_info_line);
 extern void logger_buffer_start_all (int write_info_line);
-extern void logger_buffer_flush ();
-extern void logger_buffer_adjust_log_filenames ();
+extern void logger_buffer_flush (void);
+extern void logger_buffer_adjust_log_filenames (void);
 extern void logger_buffer_free (struct t_logger_buffer *logger_buffer);
 extern int logger_buffer_add_to_infolist (struct t_infolist *infolist,
                                           struct t_logger_buffer *logger_buffer);
diff --git a/src/plugins/logger/logger-command.c b/src/plugins/logger/logger-command.c
index 98b0078dd..1d3f6f9db 100644
--- a/src/plugins/logger/logger-command.c
+++ b/src/plugins/logger/logger-command.c
@@ -33,7 +33,7 @@
  */
 
 void
-logger_list ()
+logger_list (void)
 {
     struct t_infolist *ptr_infolist;
     struct t_logger_buffer *ptr_logger_buffer;
@@ -161,7 +161,7 @@ logger_command_cb (const void *pointer, void *data,
  */
 
 void
-logger_command_init ()
+logger_command_init (void)
 {
     weechat_hook_command (
         "logger",
diff --git a/src/plugins/logger/logger-command.h b/src/plugins/logger/logger-command.h
index 924fd88ae..ea1f3189a 100644
--- a/src/plugins/logger/logger-command.h
+++ b/src/plugins/logger/logger-command.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_LOGGER_COMMAND_H
 #define WEECHAT_PLUGIN_LOGGER_COMMAND_H
 
-extern void logger_command_init ();
+extern void logger_command_init (void);
 
 #endif /* WEECHAT_PLUGIN_LOGGER_COMMAND_H */
diff --git a/src/plugins/logger/logger-config.c b/src/plugins/logger/logger-config.c
index a80ce74d7..16a2bbfc3 100644
--- a/src/plugins/logger/logger-config.c
+++ b/src/plugins/logger/logger-config.c
@@ -489,7 +489,7 @@ logger_config_get_mask (const char *name)
  */
 
 int
-logger_config_init ()
+logger_config_init (void)
 {
     logger_config_file = weechat_config_new (LOGGER_CONFIG_PRIO_NAME,
                                              NULL, NULL, NULL);
@@ -748,7 +748,7 @@ logger_config_init ()
  */
 
 int
-logger_config_read ()
+logger_config_read (void)
 {
     int rc;
 
@@ -766,7 +766,7 @@ logger_config_read ()
  */
 
 int
-logger_config_write ()
+logger_config_write (void)
 {
     return weechat_config_write (logger_config_file);
 }
@@ -776,7 +776,7 @@ logger_config_write ()
  */
 
 void
-logger_config_free ()
+logger_config_free (void)
 {
     weechat_config_free (logger_config_file);
     logger_config_file = NULL;
diff --git a/src/plugins/logger/logger-config.h b/src/plugins/logger/logger-config.h
index f56a4f7d1..3ce53fbe5 100644
--- a/src/plugins/logger/logger-config.h
+++ b/src/plugins/logger/logger-config.h
@@ -53,9 +53,9 @@ extern int logger_config_set_level (const char *name, const char *value);
 extern struct t_config_option *logger_config_get_mask (const char *name);
 extern void logger_config_color_lines_change (const void *pointer, void *data,
                                               struct t_config_option *option);
-extern int logger_config_init ();
-extern int logger_config_read ();
-extern int logger_config_write ();
-extern void logger_config_free ();
+extern int logger_config_init (void);
+extern int logger_config_read (void);
+extern int logger_config_write (void);
+extern void logger_config_free (void);
 
 #endif /* WEECHAT_PLUGIN_LOGGER_CONFIG_H */
diff --git a/src/plugins/logger/logger-info.c b/src/plugins/logger/logger-info.c
index 2abcc23b7..7dbbf8b7f 100644
--- a/src/plugins/logger/logger-info.c
+++ b/src/plugins/logger/logger-info.c
@@ -143,7 +143,7 @@ logger_info_infolist_logger_buffer_cb (const void *pointer, void *data,
  */
 
 void
-logger_info_init ()
+logger_info_init (void)
 {
     /* info hooks */
     weechat_hook_info (
diff --git a/src/plugins/logger/logger-info.h b/src/plugins/logger/logger-info.h
index 9431f6cca..1d0bbd887 100644
--- a/src/plugins/logger/logger-info.h
+++ b/src/plugins/logger/logger-info.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_LOGGER_INFO_H
 #define WEECHAT_PLUGIN_LOGGER_INFO_H
 
-extern void logger_info_init ();
+extern void logger_info_init (void);
 
 #endif /* WEECHAT_PLUGIN_LOGGER_INFO_H */
diff --git a/src/plugins/logger/logger.c b/src/plugins/logger/logger.c
index f874abb9f..3daececa4 100644
--- a/src/plugins/logger/logger.c
+++ b/src/plugins/logger/logger.c
@@ -114,7 +114,7 @@ logger_check_conditions (struct t_gui_buffer *buffer, const char *conditions)
  */
 
 char *
-logger_get_file_path ()
+logger_get_file_path (void)
 {
     char *path, *path2;
     int length;
@@ -171,7 +171,7 @@ end:
  */
 
 int
-logger_create_directory ()
+logger_create_directory (void)
 {
     int rc;
     char *file_path;
diff --git a/src/plugins/logger/logger.h b/src/plugins/logger/logger.h
index 5fe050dfa..34dcdd0e7 100644
--- a/src/plugins/logger/logger.h
+++ b/src/plugins/logger/logger.h
@@ -36,7 +36,7 @@ extern struct t_hook *logger_hook_print;
 
 extern int logger_check_conditions (struct t_gui_buffer *buffer,
                                     const char *conditions);
-extern int logger_create_directory ();
+extern int logger_create_directory (void);
 extern char *logger_build_option_name (struct t_gui_buffer *buffer);
 extern int logger_get_level_for_buffer (struct t_gui_buffer *buffer);
 extern char *logger_get_filename (struct t_gui_buffer *buffer);
diff --git a/src/plugins/lua/weechat-lua.c b/src/plugins/lua/weechat-lua.c
index 239054e8a..8c17f90a1 100644
--- a/src/plugins/lua/weechat-lua.c
+++ b/src/plugins/lua/weechat-lua.c
@@ -186,7 +186,7 @@ weechat_lua_tohashtable (lua_State *interpreter, int index, int size,
  */
 
 void
-weechat_lua_output_flush ()
+weechat_lua_output_flush (void)
 {
     const char *ptr_command;
     char *temp_buffer, *command;
@@ -838,7 +838,7 @@ weechat_lua_reload_name (const char *name)
  */
 
 void
-weechat_lua_unload_all ()
+weechat_lua_unload_all (void)
 {
     while (lua_scripts)
     {
diff --git a/src/plugins/perl/weechat-perl.c b/src/plugins/perl/weechat-perl.c
index e80003992..eac7f6642 100644
--- a/src/plugins/perl/weechat-perl.c
+++ b/src/plugins/perl/weechat-perl.c
@@ -233,7 +233,7 @@ weechat_perl_hash_to_hashtable (SV *hash, int size, const char *type_keys,
  */
 
 void
-weechat_perl_output_flush ()
+weechat_perl_output_flush (void)
 {
     const char *ptr_command;
     char *temp_buffer, *command;
@@ -784,7 +784,7 @@ weechat_perl_unload_name (const char *name)
  */
 
 void
-weechat_perl_unload_all ()
+weechat_perl_unload_all (void)
 {
     while (perl_scripts)
     {
diff --git a/src/plugins/php/weechat-php.c b/src/plugins/php/weechat-php.c
index 7f9310c18..951f4bb92 100644
--- a/src/plugins/php/weechat-php.c
+++ b/src/plugins/php/weechat-php.c
@@ -798,7 +798,7 @@ weechat_php_unload_name (const char *name)
  */
 
 void
-weechat_php_unload_all ()
+weechat_php_unload_all (void)
 {
     while (php_scripts)
     {
diff --git a/src/plugins/plugin-api-info.c b/src/plugins/plugin-api-info.c
index b2ed504cd..86b18e9ae 100644
--- a/src/plugins/plugin-api-info.c
+++ b/src/plugins/plugin-api-info.c
@@ -2125,7 +2125,7 @@ plugin_api_infolist_window_cb (const void *pointer, void *data,
  */
 
 void
-plugin_api_info_init ()
+plugin_api_info_init (void)
 {
     /* WeeChat core info hooks */
     hook_info (NULL, "version",
diff --git a/src/plugins/plugin-api-info.h b/src/plugins/plugin-api-info.h
index e62c61794..35a6b6557 100644
--- a/src/plugins/plugin-api-info.h
+++ b/src/plugins/plugin-api-info.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_PLUGIN_API_INFO_H
 #define WEECHAT_PLUGIN_PLUGIN_API_INFO_H
 
-extern void plugin_api_info_init ();
+extern void plugin_api_info_init (void);
 
 #endif /* WEECHAT_PLUGIN_PLUGIN_API_INFO_H */
diff --git a/src/plugins/plugin-api.c b/src/plugins/plugin-api.c
index ca0913a39..7231c1348 100644
--- a/src/plugins/plugin-api.c
+++ b/src/plugins/plugin-api.c
@@ -693,7 +693,7 @@ plugin_api_infolist_free (struct t_infolist *infolist)
  */
 
 void
-plugin_api_init ()
+plugin_api_init (void)
 {
     /* WeeChat core modifiers */
     hook_modifier (NULL, "color_decode",
diff --git a/src/plugins/plugin-api.h b/src/plugins/plugin-api.h
index 5ce4896f2..3ad501ad8 100644
--- a/src/plugins/plugin-api.h
+++ b/src/plugins/plugin-api.h
@@ -92,6 +92,6 @@ extern time_t plugin_api_infolist_time (struct t_infolist *infolist,
                                         const char *var);
 extern void plugin_api_infolist_free (struct t_infolist *infolist);
 
-extern void plugin_api_init ();
+extern void plugin_api_init (void);
 
 #endif /* WEECHAT_PLUGIN_PLUGIN_API_H */
diff --git a/src/plugins/plugin-config.c b/src/plugins/plugin-config.c
index 9bffa4e9c..dbd7a34e1 100644
--- a/src/plugins/plugin-config.c
+++ b/src/plugins/plugin-config.c
@@ -338,7 +338,7 @@ plugin_config_delete_desc (const void *pointer, void *data,
  */
 
 void
-plugin_config_init ()
+plugin_config_init (void)
 {
     plugin_config_file = config_file_new (NULL, PLUGIN_CONFIG_PRIO_NAME,
                                           &plugin_config_reload, NULL, NULL);
@@ -366,7 +366,7 @@ plugin_config_init ()
  */
 
 int
-plugin_config_read ()
+plugin_config_read (void)
 {
     return config_file_read (plugin_config_file);
 }
@@ -376,7 +376,7 @@ plugin_config_read ()
  */
 
 int
-plugin_config_write ()
+plugin_config_write (void)
 {
     return config_file_write (plugin_config_file);
 }
@@ -386,7 +386,7 @@ plugin_config_write ()
  */
 
 void
-plugin_config_end ()
+plugin_config_end (void)
 {
     /* free all plugin configuration options and descriptions */
     config_file_section_free_options (plugin_config_section_var);
diff --git a/src/plugins/plugin-config.h b/src/plugins/plugin-config.h
index 6c3df1555..2933d0a36 100644
--- a/src/plugins/plugin-config.h
+++ b/src/plugins/plugin-config.h
@@ -33,9 +33,9 @@ extern int plugin_config_set (const char *plugin_name, const char *option_name,
 extern void plugin_config_set_desc (const char *plugin_name,
                                     const char *option_name,
                                     const char *description);
-extern void plugin_config_init ();
-extern int plugin_config_read ();
-extern int plugin_config_write ();
-extern void plugin_config_end ();
+extern void plugin_config_init (void);
+extern int plugin_config_read (void);
+extern int plugin_config_write (void);
+extern void plugin_config_end (void);
 
 #endif /* WEECHAT_PLUGIN_PLUGIN_CONFIG_H */
diff --git a/src/plugins/plugin-script.h b/src/plugins/plugin-script.h
index 78a51e15a..735daea03 100644
--- a/src/plugins/plugin-script.h
+++ b/src/plugins/plugin-script.h
@@ -122,8 +122,8 @@ struct t_plugin_script_data
     void (*callback_load_file) (void *data, const char *filename);
 
     /* functions */
-    void (*init_before_autoload) ();
-    void (*unload_all) ();
+    void (*init_before_autoload) (void);
+    void (*unload_all) (void);
 };
 
 extern struct t_weechat_script_constant weechat_script_constants[];
diff --git a/src/plugins/plugin.c b/src/plugins/plugin.c
index 3ce3349d6..16bf2e43e 100644
--- a/src/plugins/plugin.c
+++ b/src/plugins/plugin.c
@@ -1295,7 +1295,7 @@ plugin_unload_name (const char *name)
  */
 
 void
-plugin_unload_all ()
+plugin_unload_all (void)
 {
     int plugins_loaded;
 
@@ -1349,7 +1349,7 @@ plugin_reload_name (const char *name, int argc, char **argv)
  */
 
 void
-plugin_display_short_list ()
+plugin_display_short_list (void)
 {
     char **buf;
     struct t_weechat_plugin *ptr_plugin;
@@ -1413,7 +1413,7 @@ plugin_init (char *force_plugin_autoload, int argc, char *argv[])
  */
 
 void
-plugin_end ()
+plugin_end (void)
 {
     /* write plugins configuration options */
     plugin_config_write ();
@@ -1529,7 +1529,7 @@ plugin_add_to_infolist (struct t_infolist *infolist,
  */
 
 void
-plugin_print_log ()
+plugin_print_log (void)
 {
     struct t_weechat_plugin *ptr_plugin;
 
diff --git a/src/plugins/plugin.h b/src/plugins/plugin.h
index 00d34dc08..b2b375a4f 100644
--- a/src/plugins/plugin.h
+++ b/src/plugins/plugin.h
@@ -47,15 +47,15 @@ extern void plugin_auto_load (char *force_plugin_autoload,
                               char **argv);
 extern void plugin_unload (struct t_weechat_plugin *plugin);
 extern void plugin_unload_name (const char *name);
-extern void plugin_unload_all ();
+extern void plugin_unload_all (void);
 extern void plugin_reload_name (const char *name, int argc, char **argv);
 extern void plugin_init (char *force_plugin_autoload, int argc, char *argv[]);
-extern void plugin_end ();
+extern void plugin_end (void);
 extern struct t_hdata *plugin_hdata_plugin_cb (const void *pointer,
                                                void *data,
                                                const char *hdata_name);
 extern int plugin_add_to_infolist (struct t_infolist *infolist,
                                    struct t_weechat_plugin *plugin);
-extern void plugin_print_log ();
+extern void plugin_print_log (void);
 
 #endif /* WEECHAT_PLUGIN_PLUGIN_H */
diff --git a/src/plugins/python/weechat-python.c b/src/plugins/python/weechat-python.c
index 1ddca71b1..4ae32759b 100644
--- a/src/plugins/python/weechat-python.c
+++ b/src/plugins/python/weechat-python.c
@@ -286,7 +286,7 @@ weechat_python_dict_to_hashtable (PyObject *dict, int size,
  */
 
 void
-weechat_python_output_flush ()
+weechat_python_output_flush (void)
 {
     const char *ptr_command;
     char *temp_buffer, *command;
@@ -602,7 +602,7 @@ end:
  * Initializes the "weechat" module.
  */
 
-static PyObject *weechat_python_init_module_weechat ()
+static PyObject *weechat_python_init_module_weechat (void)
 {
     PyObject *weechat_module;
     int i;
@@ -645,7 +645,7 @@ static PyObject *weechat_python_init_module_weechat ()
  */
 
 void
-weechat_python_set_output ()
+weechat_python_set_output (void)
 {
     PyObject *weechat_outputs;
 
@@ -981,7 +981,7 @@ weechat_python_unload_name (const char *name)
  */
 
 void
-weechat_python_unload_all ()
+weechat_python_unload_all (void)
 {
     while (python_scripts)
     {
@@ -1089,7 +1089,7 @@ weechat_python_eval (struct t_gui_buffer *buffer, int send_to_buffer_as_input,
  */
 
 void
-weechat_python_init_before_autoload ()
+weechat_python_init_before_autoload (void)
 {
 #if PY_VERSION_HEX >= 0x030C0000 && PY_VERSION_HEX < 0x030D0000
     /*
@@ -1308,7 +1308,7 @@ weechat_python_info_eval_cb (const void *pointer, void *data,
  */
 
 struct t_infolist *
-weechat_python_infolist_functions ()
+weechat_python_infolist_functions (void)
 {
     struct t_infolist *infolist;
     struct t_infolist_item *item;
@@ -1340,7 +1340,7 @@ weechat_python_infolist_functions ()
  */
 
 struct t_infolist *
-weechat_python_infolist_constants ()
+weechat_python_infolist_constants (void)
 {
     struct t_infolist *infolist;
     struct t_infolist_item *item;
diff --git a/src/plugins/relay/api/remote/relay-remote-network.c b/src/plugins/relay/api/remote/relay-remote-network.c
index 0b23a444b..c8a93aff4 100644
--- a/src/plugins/relay/api/remote/relay-remote-network.c
+++ b/src/plugins/relay/api/remote/relay-remote-network.c
@@ -1383,7 +1383,7 @@ relay_remote_network_url_handshake_cb (const void *pointer,
  */
 
 char *
-relay_remote_network_get_handshake_request ()
+relay_remote_network_get_handshake_request (void)
 {
     cJSON *json, *json_algos;
     char *result;
diff --git a/src/plugins/relay/irc/relay-irc.c b/src/plugins/relay/irc/relay-irc.c
index 0fb56f38c..ba9f3982e 100644
--- a/src/plugins/relay/irc/relay-irc.c
+++ b/src/plugins/relay/irc/relay-irc.c
@@ -1392,7 +1392,7 @@ relay_irc_get_supported_caps (struct t_relay_client *client)
  */
 
 struct t_arraylist *
-relay_irc_get_list_caps ()
+relay_irc_get_list_caps (void)
 {
     struct t_arraylist *list_capab;
     int i;
diff --git a/src/plugins/relay/relay-bar-item.c b/src/plugins/relay/relay-bar-item.c
index fce7c63e5..3dbbc8ffa 100644
--- a/src/plugins/relay/relay-bar-item.c
+++ b/src/plugins/relay/relay-bar-item.c
@@ -93,7 +93,7 @@ relay_bar_item_input_prompt (const void *pointer, void *data,
  */
 
 void
-relay_bar_item_init ()
+relay_bar_item_init (void)
 {
     weechat_bar_item_new ("input_prompt",
                           &relay_bar_item_input_prompt, NULL, NULL);
diff --git a/src/plugins/relay/relay-bar-item.h b/src/plugins/relay/relay-bar-item.h
index 3d08bf05d..4da118ed5 100644
--- a/src/plugins/relay/relay-bar-item.h
+++ b/src/plugins/relay/relay-bar-item.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_RELAY_BAR_ITEM_H
 #define WEECHAT_PLUGIN_RELAY_BAR_ITEM_H
 
-extern void relay_bar_item_init ();
+extern void relay_bar_item_init (void);
 
 #endif /* WEECHAT_PLUGIN_RELAY_BAR_ITEM_H */
diff --git a/src/plugins/relay/relay-buffer.c b/src/plugins/relay/relay-buffer.c
index 7d491e789..e084218ec 100644
--- a/src/plugins/relay/relay-buffer.c
+++ b/src/plugins/relay/relay-buffer.c
@@ -276,7 +276,7 @@ relay_buffer_close_cb (const void *pointer, void *data,
  */
 
 void
-relay_buffer_open ()
+relay_buffer_open (void)
 {
     struct t_hashtable *buffer_props;
 
diff --git a/src/plugins/relay/relay-buffer.h b/src/plugins/relay/relay-buffer.h
index e185f93bb..899af9e68 100644
--- a/src/plugins/relay/relay-buffer.h
+++ b/src/plugins/relay/relay-buffer.h
@@ -32,6 +32,6 @@ extern int relay_buffer_input_cb (const void *pointer, void *data,
                                   const char *input_data);
 extern int relay_buffer_close_cb (const void *pointer, void *data,
                                   struct t_gui_buffer *buffer);
-extern void relay_buffer_open ();
+extern void relay_buffer_open (void);
 
 #endif /* WEECHAT_PLUGIN_RELAY_BUFFER_H */
diff --git a/src/plugins/relay/relay-client.c b/src/plugins/relay/relay-client.c
index ea4156877..dfa0bb984 100644
--- a/src/plugins/relay/relay-client.c
+++ b/src/plugins/relay/relay-client.c
@@ -1303,7 +1303,7 @@ relay_client_send (struct t_relay_client *client,
  */
 
 void
-relay_client_timer ()
+relay_client_timer (void)
 {
     struct t_relay_client *ptr_client, *ptr_next_client;
     int purge_delay, auth_timeout;
@@ -1947,7 +1947,7 @@ relay_client_free (struct t_relay_client *client)
  */
 
 void
-relay_client_free_all ()
+relay_client_free_all (void)
 {
     while (relay_clients)
     {
@@ -1973,7 +1973,7 @@ relay_client_disconnect (struct t_relay_client *client)
  */
 
 void
-relay_client_disconnect_all ()
+relay_client_disconnect_all (void)
 {
     struct t_relay_client *ptr_client;
 
@@ -2171,7 +2171,7 @@ relay_client_add_to_infolist (struct t_infolist *infolist,
  */
 
 void
-relay_client_print_log ()
+relay_client_print_log (void)
 {
     struct t_relay_client *ptr_client;
 
diff --git a/src/plugins/relay/relay-client.h b/src/plugins/relay/relay-client.h
index 92dbaaffb..ae19ef606 100644
--- a/src/plugins/relay/relay-client.h
+++ b/src/plugins/relay/relay-client.h
@@ -131,19 +131,19 @@ extern int relay_client_send (struct t_relay_client *client,
                               enum t_relay_msg_type msg_type,
                               const char *data,
                               int data_size, const char *message_raw_buffer);
-extern void relay_client_timer ();
+extern void relay_client_timer (void);
 extern struct t_relay_client *relay_client_new (int sock, const char *address,
                                                 struct t_relay_server *server);
 extern struct t_relay_client *relay_client_new_with_infolist (struct t_infolist *infolist);
 extern void relay_client_set_status (struct t_relay_client *client,
                                      enum t_relay_status status);
 extern void relay_client_free (struct t_relay_client *client);
-extern void relay_client_free_all ();
+extern void relay_client_free_all (void);
 extern void relay_client_disconnect (struct t_relay_client *client);
-extern void relay_client_disconnect_all ();
+extern void relay_client_disconnect_all (void);
 extern int relay_client_add_to_infolist (struct t_infolist *infolist,
                                          struct t_relay_client *client,
                                          int force_disconnected_state);
-extern void relay_client_print_log ();
+extern void relay_client_print_log (void);
 
 #endif /* WEECHAT_PLUGIN_RELAY_CLIENT_H */
diff --git a/src/plugins/relay/relay-command.c b/src/plugins/relay/relay-command.c
index d7c50cc9d..9385e5af6 100644
--- a/src/plugins/relay/relay-command.c
+++ b/src/plugins/relay/relay-command.c
@@ -126,7 +126,7 @@ relay_command_client_list (int full)
  */
 
 void
-relay_command_server_list ()
+relay_command_server_list (void)
 {
     struct t_relay_server *ptr_server;
     char date_start[128];
@@ -868,7 +868,7 @@ relay_command_remote (const void *pointer, void *data,
  */
 
 void
-relay_command_init ()
+relay_command_init (void)
 {
     weechat_hook_command (
         "relay",
diff --git a/src/plugins/relay/relay-command.h b/src/plugins/relay/relay-command.h
index 7be345ffc..53c682c26 100644
--- a/src/plugins/relay/relay-command.h
+++ b/src/plugins/relay/relay-command.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_RELAY_COMMAND_H
 #define WEECHAT_PLUGIN_RELAY_COMMAND_H
 
-extern void relay_command_init ();
+extern void relay_command_init (void);
 
 #endif /* WEECHAT_PLUGIN_RELAY_COMMAND_H */
diff --git a/src/plugins/relay/relay-completion.c b/src/plugins/relay/relay-completion.c
index 7d5df7e50..e847a1da5 100644
--- a/src/plugins/relay/relay-completion.c
+++ b/src/plugins/relay/relay-completion.c
@@ -199,7 +199,7 @@ relay_completion_remotes_cb (const void *pointer, void *data,
  */
 
 void
-relay_completion_init ()
+relay_completion_init (void)
 {
     weechat_hook_completion ("relay_protocol_name",
                              N_("all possible protocol.name for relay plugin"),
diff --git a/src/plugins/relay/relay-completion.h b/src/plugins/relay/relay-completion.h
index fd8e583c7..4bd0d63c4 100644
--- a/src/plugins/relay/relay-completion.h
+++ b/src/plugins/relay/relay-completion.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_RELAY_COMPLETION_H
 #define WEECHAT_PLUGIN_RELAY_COMPLETION_H
 
-extern void relay_completion_init ();
+extern void relay_completion_init (void);
 
 #endif /* WEECHAT_PLUGIN_RELAY_COMPLETION_H */
diff --git a/src/plugins/relay/relay-config.c b/src/plugins/relay/relay-config.c
index 1e93bcc22..b57cf210e 100644
--- a/src/plugins/relay/relay-config.c
+++ b/src/plugins/relay/relay-config.c
@@ -1156,7 +1156,7 @@ relay_config_create_option_temp (struct t_relay_remote *temp_remote,
  */
 
 void
-relay_config_use_temp_remotes ()
+relay_config_use_temp_remotes (void)
 {
     struct t_relay_remote *ptr_temp_remote, *next_temp_remote;
     int i, num_options_ok;
@@ -1414,7 +1414,7 @@ relay_config_update_cb (const void *pointer, void *data,
  */
 
 int
-relay_config_init ()
+relay_config_init (void)
 {
     relay_config_file = weechat_config_new (RELAY_CONFIG_PRIO_NAME,
                                             &relay_config_reload, NULL, NULL);
@@ -1931,7 +1931,7 @@ relay_config_init ()
  */
 
 int
-relay_config_read ()
+relay_config_read (void)
 {
     int rc;
 
@@ -1953,7 +1953,7 @@ relay_config_read ()
  */
 
 int
-relay_config_write ()
+relay_config_write (void)
 {
     return weechat_config_write (relay_config_file);
 }
@@ -1963,7 +1963,7 @@ relay_config_write ()
  */
 
 void
-relay_config_free ()
+relay_config_free (void)
 {
     weechat_config_free (relay_config_file);
     relay_config_file = NULL;
diff --git a/src/plugins/relay/relay-config.h b/src/plugins/relay/relay-config.h
index f5b64cdcb..d35c7ffa2 100644
--- a/src/plugins/relay/relay-config.h
+++ b/src/plugins/relay/relay-config.h
@@ -97,9 +97,9 @@ extern int relay_config_check_path_available (const char *path);
 extern struct t_config_option *relay_config_create_remote_option (const char *remote_name,
                                                                   int index_option,
                                                                   const char *value);
-extern int relay_config_init ();
-extern int relay_config_read ();
-extern int relay_config_write ();
-extern void relay_config_free ();
+extern int relay_config_init (void);
+extern int relay_config_read (void);
+extern int relay_config_write (void);
+extern void relay_config_free (void);
 
 #endif /* WEECHAT_PLUGIN_RELAY_CONFIG_H */
diff --git a/src/plugins/relay/relay-http.c b/src/plugins/relay/relay-http.c
index 90969dc9b..e60d926e0 100644
--- a/src/plugins/relay/relay-http.c
+++ b/src/plugins/relay/relay-http.c
@@ -82,7 +82,7 @@ relay_http_request_reinit (struct t_relay_http_request *request)
  */
 
 struct t_relay_http_request *
-relay_http_request_alloc ()
+relay_http_request_alloc (void)
 {
     struct t_relay_http_request *new_request;
 
@@ -1380,7 +1380,7 @@ relay_http_request_free (struct t_relay_http_request *request)
  */
 
 struct t_relay_http_response *
-relay_http_response_alloc ()
+relay_http_response_alloc (void)
 {
     struct t_relay_http_response *new_response;
 
diff --git a/src/plugins/relay/relay-http.h b/src/plugins/relay/relay-http.h
index 2fdd9fcd9..65f8d46ad 100644
--- a/src/plugins/relay/relay-http.h
+++ b/src/plugins/relay/relay-http.h
@@ -88,7 +88,7 @@ struct t_relay_http_response
 };
 
 extern void relay_http_request_reinit (struct t_relay_http_request *request);
-extern struct t_relay_http_request *relay_http_request_alloc ();
+extern struct t_relay_http_request *relay_http_request_alloc (void);
 extern int relay_http_get_param_boolean (struct t_relay_http_request *request,
                                          const char *name, int default_value);
 extern long relay_http_get_param_long (struct t_relay_http_request *request,
@@ -112,7 +112,7 @@ extern int relay_http_send_error_json (struct t_relay_client *client,
                                        const char *headers,
                                        const char *format, ...);
 extern void relay_http_request_free (struct t_relay_http_request *request);
-extern struct t_relay_http_response *relay_http_response_alloc ();
+extern struct t_relay_http_response *relay_http_response_alloc (void);
 extern struct t_relay_http_response *relay_http_parse_response (const char *data);
 extern void relay_http_response_free (struct t_relay_http_response *response);
 extern void relay_http_print_log_request (struct t_relay_http_request *request);
diff --git a/src/plugins/relay/relay-info.c b/src/plugins/relay/relay-info.c
index f20470dc3..097bd3a36 100644
--- a/src/plugins/relay/relay-info.c
+++ b/src/plugins/relay/relay-info.c
@@ -227,7 +227,7 @@ relay_info_infolist_relay_cb (const void *pointer, void *data,
  */
 
 void
-relay_info_init ()
+relay_info_init (void)
 {
     /* info hooks */
     weechat_hook_info (
diff --git a/src/plugins/relay/relay-info.h b/src/plugins/relay/relay-info.h
index 1c5b5fe9a..89d0cd9bd 100644
--- a/src/plugins/relay/relay-info.h
+++ b/src/plugins/relay/relay-info.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_RELAY_INFO_H
 #define WEECHAT_PLUGIN_RELAY_INFO_H
 
-extern void relay_info_init ();
+extern void relay_info_init (void);
 
 #endif /* WEECHAT_PLUGIN_RELAY_INFO_H */
diff --git a/src/plugins/relay/relay-network.c b/src/plugins/relay/relay-network.c
index 4426dbe96..7c0ffc646 100644
--- a/src/plugins/relay/relay-network.c
+++ b/src/plugins/relay/relay-network.c
@@ -138,7 +138,7 @@ relay_network_set_tls_cert_key (int verbose)
  */
 
 void
-relay_network_set_priority ()
+relay_network_set_priority (void)
 {
     if (gnutls_priority_init (relay_gnutls_priority_cache,
                               weechat_config_string (
@@ -158,7 +158,7 @@ relay_network_set_priority ()
  */
 
 void
-relay_network_init ()
+relay_network_init (void)
 {
     relay_network_init_ok = 0;
     relay_network_init_tls_cert_key_ok = 0;
@@ -180,7 +180,7 @@ relay_network_init ()
  */
 
 void
-relay_network_end ()
+relay_network_end (void)
 {
     if (relay_network_init_ok)
     {
diff --git a/src/plugins/relay/relay-network.h b/src/plugins/relay/relay-network.h
index 3e2a63629..e1655e6c4 100644
--- a/src/plugins/relay/relay-network.h
+++ b/src/plugins/relay/relay-network.h
@@ -30,8 +30,8 @@ extern gnutls_priority_t *relay_gnutls_priority_cache;
 extern gnutls_dh_params_t *relay_gnutls_dh_params;
 
 extern void relay_network_set_tls_cert_key (int verbose);
-extern void relay_network_set_priority ();
-extern void relay_network_init ();
-extern void relay_network_end ();
+extern void relay_network_set_priority (void);
+extern void relay_network_init (void);
+extern void relay_network_end (void);
 
 #endif /* WEECHAT_PLUGIN_RELAY_NETWORK_H */
diff --git a/src/plugins/relay/relay-raw.c b/src/plugins/relay/relay-raw.c
index b828b0b95..e9bbaa24f 100644
--- a/src/plugins/relay/relay-raw.c
+++ b/src/plugins/relay/relay-raw.c
@@ -164,7 +164,7 @@ relay_raw_message_free (struct t_relay_raw_message *raw_message)
  */
 
 void
-relay_raw_message_free_all ()
+relay_raw_message_free_all (void)
 {
     while (relay_raw_messages)
     {
@@ -177,7 +177,7 @@ relay_raw_message_free_all ()
  */
 
 void
-relay_raw_message_remove_old ()
+relay_raw_message_remove_old (void)
 {
     int max_messages;
 
diff --git a/src/plugins/relay/relay-raw.h b/src/plugins/relay/relay-raw.h
index 3865f8262..baab609fa 100644
--- a/src/plugins/relay/relay-raw.h
+++ b/src/plugins/relay/relay-raw.h
@@ -61,7 +61,7 @@ extern void relay_raw_print_client (struct t_relay_client *client,
 extern void relay_raw_print_remote (struct t_relay_remote *remote,
                                     enum t_relay_msg_type msg_type, int flags,
                                     const char *data, int data_size);
-extern void relay_raw_message_free_all ();
+extern void relay_raw_message_free_all (void);
 extern int relay_raw_add_to_infolist (struct t_infolist *infolist,
                                       struct t_relay_raw_message *raw_message);
 
diff --git a/src/plugins/relay/relay-remote.c b/src/plugins/relay/relay-remote.c
index 67d5a939c..92b3e488f 100644
--- a/src/plugins/relay/relay-remote.c
+++ b/src/plugins/relay/relay-remote.c
@@ -708,7 +708,7 @@ relay_remote_auto_connect_timer_cb (const void *pointer, void *data,
  */
 
 void
-relay_remote_auto_connect ()
+relay_remote_auto_connect (void)
 {
     weechat_hook_timer (1, 0, 1,
                         &relay_remote_auto_connect_timer_cb, NULL, NULL);
@@ -920,7 +920,7 @@ relay_remote_reconnect (struct t_relay_remote *remote)
  */
 
 void
-relay_remote_timer ()
+relay_remote_timer (void)
 {
     struct t_relay_remote *ptr_remote, *ptr_next_remote;
     time_t current_time;
@@ -949,7 +949,7 @@ relay_remote_timer ()
  */
 
 void
-relay_remote_disconnect_all ()
+relay_remote_disconnect_all (void)
 {
     struct t_relay_remote *ptr_remote;
 
@@ -1021,7 +1021,7 @@ relay_remote_free (struct t_relay_remote *remote)
  */
 
 void
-relay_remote_free_all ()
+relay_remote_free_all (void)
 {
     while (relay_remotes)
     {
@@ -1135,7 +1135,7 @@ relay_remote_add_to_infolist (struct t_infolist *infolist,
  */
 
 void
-relay_remote_print_log ()
+relay_remote_print_log (void)
 {
     struct t_relay_remote *ptr_remote;
 
diff --git a/src/plugins/relay/relay-remote.h b/src/plugins/relay/relay-remote.h
index 719ca8c2d..a9ead681a 100644
--- a/src/plugins/relay/relay-remote.h
+++ b/src/plugins/relay/relay-remote.h
@@ -103,21 +103,21 @@ extern struct t_relay_remote *relay_remote_new_with_infolist (struct t_infolist
 extern void relay_remote_set_status (struct t_relay_remote *remote,
                                      enum t_relay_status status);
 extern int relay_remote_connect (struct t_relay_remote *remote);
-extern void relay_remote_auto_connect ();
+extern void relay_remote_auto_connect (void);
 extern int relay_remote_send (struct t_relay_remote *remote, const char *json);
 extern int relay_remote_disconnect (struct t_relay_remote *remote);
 extern void relay_remote_reconnect_schedule (struct t_relay_remote *remote);
 extern int relay_remote_reconnect (struct t_relay_remote *remote);
-extern void relay_remote_timer ();
-extern void relay_remote_disconnect_all ();
+extern void relay_remote_timer (void);
+extern void relay_remote_disconnect_all (void);
 extern int relay_remote_rename (struct t_relay_remote *remote, const char *name);
 extern void relay_remote_buffer_input (struct t_gui_buffer *buffer,
                                        const char *input_data);
 extern void relay_remote_free (struct t_relay_remote *remote);
-extern void relay_remote_free_all ();
+extern void relay_remote_free_all (void);
 extern int relay_remote_add_to_infolist (struct t_infolist *infolist,
                                          struct t_relay_remote *remote,
                                          int force_disconnected_state);
-extern void relay_remote_print_log ();
+extern void relay_remote_print_log (void);
 
 #endif /* WEECHAT_PLUGIN_RELAY_REMOTE_H */
diff --git a/src/plugins/relay/relay-server.c b/src/plugins/relay/relay-server.c
index 0251c9878..05cdfc12b 100644
--- a/src/plugins/relay/relay-server.c
+++ b/src/plugins/relay/relay-server.c
@@ -976,7 +976,7 @@ relay_server_free (struct t_relay_server *server)
  */
 
 void
-relay_server_free_all ()
+relay_server_free_all (void)
 {
     while (relay_servers)
     {
@@ -1040,7 +1040,7 @@ relay_server_add_to_infolist (struct t_infolist *infolist,
  */
 
 void
-relay_server_print_log ()
+relay_server_print_log (void)
 {
     struct t_relay_server *ptr_server;
 
diff --git a/src/plugins/relay/relay-server.h b/src/plugins/relay/relay-server.h
index ff063c2fc..e473dace8 100644
--- a/src/plugins/relay/relay-server.h
+++ b/src/plugins/relay/relay-server.h
@@ -70,9 +70,9 @@ extern void relay_server_update_path (struct t_relay_server *server,
                                       const char *path);
 extern void relay_server_update_port (struct t_relay_server *server, int port);
 extern void relay_server_free (struct t_relay_server *server);
-extern void relay_server_free_all ();
+extern void relay_server_free_all (void);
 extern int relay_server_add_to_infolist (struct t_infolist *infolist,
                                          struct t_relay_server *server);
-extern void relay_server_print_log ();
+extern void relay_server_print_log (void);
 
 #endif /* WEECHAT_PLUGIN_RELAY_SERVER_H */
diff --git a/src/plugins/relay/relay-upgrade.c b/src/plugins/relay/relay-upgrade.c
index c9daa659e..66f8ec802 100644
--- a/src/plugins/relay/relay-upgrade.c
+++ b/src/plugins/relay/relay-upgrade.c
@@ -146,7 +146,7 @@ relay_upgrade_save (int force_disconnected_state)
  */
 
 void
-relay_upgrade_set_buffer_callbacks ()
+relay_upgrade_set_buffer_callbacks (void)
 {
     struct t_infolist *infolist;
     struct t_gui_buffer *ptr_buffer;
@@ -238,7 +238,7 @@ relay_upgrade_read_cb (const void *pointer, void *data,
  */
 
 int
-relay_upgrade_load ()
+relay_upgrade_load (void)
 {
     int rc;
     struct t_upgrade_file *upgrade_file;
diff --git a/src/plugins/relay/relay-upgrade.h b/src/plugins/relay/relay-upgrade.h
index 5d522e536..7c70fd5b8 100644
--- a/src/plugins/relay/relay-upgrade.h
+++ b/src/plugins/relay/relay-upgrade.h
@@ -32,6 +32,6 @@ enum t_relay_upgrade_type
 };
 
 extern int relay_upgrade_save (int force_disconnected_state);
-extern int relay_upgrade_load ();
+extern int relay_upgrade_load (void);
 
 #endif /* WEECHAT_PLUGIN_RELAY_UPGRADE_H */
diff --git a/src/plugins/relay/relay-websocket.c b/src/plugins/relay/relay-websocket.c
index 9c61663be..a6cebfdcc 100644
--- a/src/plugins/relay/relay-websocket.c
+++ b/src/plugins/relay/relay-websocket.c
@@ -39,7 +39,7 @@
  */
 
 struct t_relay_websocket_deflate *
-relay_websocket_deflate_alloc ()
+relay_websocket_deflate_alloc (void)
 {
     struct t_relay_websocket_deflate *new_ws_deflate;
 
diff --git a/src/plugins/relay/relay-websocket.h b/src/plugins/relay/relay-websocket.h
index 21da4a054..4b1a36f44 100644
--- a/src/plugins/relay/relay-websocket.h
+++ b/src/plugins/relay/relay-websocket.h
@@ -64,7 +64,7 @@ struct t_relay_websocket_frame
     char *payload;                     /* payload                           */
 };
 
-extern struct t_relay_websocket_deflate *relay_websocket_deflate_alloc ();
+extern struct t_relay_websocket_deflate *relay_websocket_deflate_alloc (void);
 extern int relay_websocket_deflate_init_stream_deflate (struct t_relay_websocket_deflate *ws_deflate);
 extern int relay_websocket_deflate_init_stream_inflate (struct t_relay_websocket_deflate *ws_deflate);
 extern void relay_websocket_deflate_reinit (struct t_relay_websocket_deflate *ws_deflate);
diff --git a/src/plugins/relay/weechat/relay-weechat-nicklist.c b/src/plugins/relay/weechat/relay-weechat-nicklist.c
index 0a2637459..1268f733c 100644
--- a/src/plugins/relay/weechat/relay-weechat-nicklist.c
+++ b/src/plugins/relay/weechat/relay-weechat-nicklist.c
@@ -35,7 +35,7 @@
  */
 
 struct t_relay_weechat_nicklist *
-relay_weechat_nicklist_new ()
+relay_weechat_nicklist_new (void)
 {
     struct t_relay_weechat_nicklist *new_nicklist;
 
diff --git a/src/plugins/relay/weechat/relay-weechat-nicklist.h b/src/plugins/relay/weechat/relay-weechat-nicklist.h
index 711388355..041e8428b 100644
--- a/src/plugins/relay/weechat/relay-weechat-nicklist.h
+++ b/src/plugins/relay/weechat/relay-weechat-nicklist.h
@@ -47,7 +47,7 @@ struct t_relay_weechat_nicklist
     struct t_relay_weechat_nicklist_item *items; /* nicklist items          */
 };
 
-extern struct t_relay_weechat_nicklist *relay_weechat_nicklist_new ();
+extern struct t_relay_weechat_nicklist *relay_weechat_nicklist_new (void);
 extern void relay_weechat_nicklist_add_item (struct t_relay_weechat_nicklist *nicklist,
                                              char diff,
                                              struct t_gui_nick_group *group,
diff --git a/src/plugins/ruby/weechat-ruby.c b/src/plugins/ruby/weechat-ruby.c
index 10940f491..21e7ec572 100644
--- a/src/plugins/ruby/weechat-ruby.c
+++ b/src/plugins/ruby/weechat-ruby.c
@@ -348,7 +348,7 @@ weechat_ruby_output_flush_ruby (VALUE self)
  */
 
 void
-weechat_ruby_output_flush ()
+weechat_ruby_output_flush (void)
 {
     const char *ptr_command;
     char *temp_buffer, *command;
@@ -847,7 +847,7 @@ weechat_ruby_reload_name (const char *name)
  */
 
 void
-weechat_ruby_unload_all ()
+weechat_ruby_unload_all (void)
 {
     while (ruby_scripts)
     {
diff --git a/src/plugins/script/script-action.c b/src/plugins/script/script-action.c
index d02177021..2d6de5b2e 100644
--- a/src/plugins/script/script-action.c
+++ b/src/plugins/script/script-action.c
@@ -46,7 +46,7 @@ void script_action_run_install (int quiet);
  */
 
 void
-script_action_run_list ()
+script_action_run_list (void)
 {
     int i, scripts_loaded;
     char hdata_name[128];
@@ -646,7 +646,7 @@ script_action_install_url_cb (const void *pointer, void *data,
  */
 
 struct t_script_repo *
-script_action_get_next_script_to_install ()
+script_action_get_next_script_to_install (void)
 {
     struct t_script_repo *ptr_script, *ptr_script_to_install;
 
@@ -1200,7 +1200,7 @@ script_action_run_show (const char *name, int quiet)
  */
 
 void
-script_action_run_showdiff ()
+script_action_run_showdiff (void)
 {
     char str_command[64];
     struct t_gui_window *window;
@@ -1263,7 +1263,7 @@ script_action_add (struct t_gui_buffer *buffer, const char *action)
  */
 
 void
-script_action_clear ()
+script_action_clear (void)
 {
     if (script_actions)
         weechat_string_dyn_copy (script_actions, NULL);
@@ -1278,7 +1278,7 @@ script_action_clear ()
  */
 
 int
-script_action_run_all ()
+script_action_run_all (void)
 {
     char **actions, **argv, **argv_eol, *ptr_action;
     int num_actions, argc, i, j, quiet, script_found;
@@ -1623,7 +1623,7 @@ script_action_schedule (struct t_gui_buffer *buffer,
  */
 
 void
-script_action_end ()
+script_action_end (void)
 {
     if (script_actions)
     {
diff --git a/src/plugins/script/script-action.h b/src/plugins/script/script-action.h
index a7d050ce8..6211691bc 100644
--- a/src/plugins/script/script-action.h
+++ b/src/plugins/script/script-action.h
@@ -22,12 +22,12 @@
 
 extern char **script_actions;
 
-extern int script_action_run_all ();
+extern int script_action_run_all (void);
 extern void script_action_schedule (struct t_gui_buffer *buffer,
                                     const char *action,
                                     int need_repository,
                                     int error_repository,
                                     int quiet);
-extern void script_action_end ();
+extern void script_action_end (void);
 
 #endif /* WEECHAT_PLUGIN_SCRIPT_ACTION_H */
diff --git a/src/plugins/script/script-buffer.c b/src/plugins/script/script-buffer.c
index c71291ecf..4e3def62e 100644
--- a/src/plugins/script/script-buffer.c
+++ b/src/plugins/script/script-buffer.c
@@ -901,7 +901,7 @@ script_buffer_get_window_info (struct t_gui_window *window,
  */
 
 void
-script_buffer_check_line_outside_window ()
+script_buffer_check_line_outside_window (void)
 {
     struct t_gui_window *window;
     int start_line_y, chat_height;
@@ -1073,7 +1073,7 @@ script_buffer_close_cb (const void *pointer, void *data,
  */
 
 void
-script_buffer_set_callbacks ()
+script_buffer_set_callbacks (void)
 {
     struct t_gui_buffer *ptr_buffer;
 
@@ -1142,7 +1142,7 @@ script_buffer_set_keys (struct t_hashtable *hashtable)
  */
 
 void
-script_buffer_set_localvar_filter ()
+script_buffer_set_localvar_filter (void)
 {
     if (!script_buffer)
         return;
@@ -1156,7 +1156,7 @@ script_buffer_set_localvar_filter ()
  */
 
 void
-script_buffer_open ()
+script_buffer_open (void)
 {
     struct t_hashtable *buffer_props;
 
diff --git a/src/plugins/script/script-buffer.h b/src/plugins/script/script-buffer.h
index cdca5b2ec..7776d56c2 100644
--- a/src/plugins/script/script-buffer.h
+++ b/src/plugins/script/script-buffer.h
@@ -35,7 +35,7 @@ extern void script_buffer_set_current_line (int line);
 extern void script_buffer_show_detail_script (struct t_script_repo *script);
 extern void script_buffer_get_window_info (struct t_gui_window *window,
                                            int *start_line_y, int *chat_height);
-extern void script_buffer_check_line_outside_window ();
+extern void script_buffer_check_line_outside_window (void);
 extern int script_buffer_window_scrolled_cb (const void *pointer, void *data,
                                              const char *signal,
                                              const char *type_data,
@@ -45,9 +45,9 @@ extern int script_buffer_input_cb (const void *pointer, void *data,
                                    const char *input_data);
 extern int script_buffer_close_cb (const void *pointer, void *data,
                                    struct t_gui_buffer *buffer);
-extern void script_buffer_set_callbacks ();
+extern void script_buffer_set_callbacks (void);
 extern void script_buffer_set_keys (struct t_hashtable *hashtable);
-extern void script_buffer_set_localvar_filter ();
-extern void script_buffer_open ();
+extern void script_buffer_set_localvar_filter (void);
+extern void script_buffer_open (void);
 
 #endif /* WEECHAT_PLUGIN_SCRIPT_BUFFER_H */
diff --git a/src/plugins/script/script-command.c b/src/plugins/script/script-command.c
index 79ceb7b15..a620ba712 100644
--- a/src/plugins/script/script-command.c
+++ b/src/plugins/script/script-command.c
@@ -315,7 +315,7 @@ script_command_script (const void *pointer, void *data,
  */
 
 void
-script_command_init ()
+script_command_init (void)
 {
     weechat_hook_command (
         "script",
diff --git a/src/plugins/script/script-command.h b/src/plugins/script/script-command.h
index a79dce540..17ec99ddf 100644
--- a/src/plugins/script/script-command.h
+++ b/src/plugins/script/script-command.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_SCRIPT_COMMAND_H
 #define WEECHAT_PLUGIN_SCRIPT_COMMAND_H
 
-extern void script_command_init ();
+extern void script_command_init (void);
 
 #endif /* WEECHAT_PLUGIN_SCRIPT_COMMAND_H */
diff --git a/src/plugins/script/script-completion.c b/src/plugins/script/script-completion.c
index 64a825211..e54ac3fed 100644
--- a/src/plugins/script/script-completion.c
+++ b/src/plugins/script/script-completion.c
@@ -287,7 +287,7 @@ script_completion_tags_cb (const void *pointer, void *data,
  */
 
 void
-script_completion_init ()
+script_completion_init (void)
 {
     weechat_hook_completion ("script_languages",
                              N_("list of script languages"),
diff --git a/src/plugins/script/script-completion.h b/src/plugins/script/script-completion.h
index 54f5720d2..888533ddd 100644
--- a/src/plugins/script/script-completion.h
+++ b/src/plugins/script/script-completion.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_SCRIPT_COMPLETION_H
 #define WEECHAT_PLUGIN_SCRIPT_COMPLETION_H
 
-extern void script_completion_init ();
+extern void script_completion_init (void);
 
 #endif /* WEECHAT_PLUGIN_SCRIPT_COMPLETION_H */
diff --git a/src/plugins/script/script-config.c b/src/plugins/script/script-config.c
index 4290af009..878c36cdb 100644
--- a/src/plugins/script/script-config.c
+++ b/src/plugins/script/script-config.c
@@ -101,7 +101,7 @@ struct t_config_option *script_config_scripts_url = NULL;
  */
 
 const char *
-script_config_get_diff_command ()
+script_config_get_diff_command (void)
 {
     const char *diff_command;
     char *dir_separator;
@@ -159,7 +159,7 @@ script_config_get_diff_command ()
  */
 
 char *
-script_config_get_xml_filename ()
+script_config_get_xml_filename (void)
 {
     char *path, *filename;
     struct t_hashtable *options;
@@ -403,7 +403,7 @@ script_config_reload (const void *pointer, void *data,
  */
 
 int
-script_config_init ()
+script_config_init (void)
 {
     script_config_file = weechat_config_new (
         SCRIPT_CONFIG_PRIO_NAME,
@@ -798,7 +798,7 @@ script_config_init ()
  */
 
 int
-script_config_read ()
+script_config_read (void)
 {
     return weechat_config_read (script_config_file);
 }
@@ -808,7 +808,7 @@ script_config_read ()
  */
 
 int
-script_config_write ()
+script_config_write (void)
 {
     return weechat_config_write (script_config_file);
 }
@@ -818,7 +818,7 @@ script_config_write ()
  */
 
 void
-script_config_free ()
+script_config_free (void)
 {
     weechat_config_free (script_config_file);
     script_config_file = NULL;
diff --git a/src/plugins/script/script-config.h b/src/plugins/script/script-config.h
index 49b59b691..d7853bd01 100644
--- a/src/plugins/script/script-config.h
+++ b/src/plugins/script/script-config.h
@@ -69,15 +69,15 @@ extern struct t_config_option *script_config_scripts_hold;
 extern struct t_config_option *script_config_scripts_path;
 extern struct t_config_option *script_config_scripts_url;
 
-extern const char *script_config_get_diff_command ();
-extern char *script_config_get_xml_filename ();
+extern const char *script_config_get_diff_command (void);
+extern char *script_config_get_xml_filename (void);
 extern char *script_config_get_script_download_filename (struct t_script_repo *script,
                                                          const char *suffix);
 extern void script_config_hold (const char *name_with_extension);
 extern void script_config_unhold (const char *name_with_extension);
-extern int script_config_init ();
-extern int script_config_read ();
-extern int script_config_write ();
-extern void script_config_free ();
+extern int script_config_init (void);
+extern int script_config_read (void);
+extern int script_config_write (void);
+extern void script_config_free (void);
 
 #endif /* WEECHAT_PLUGIN_SCRIPT_CONFIG_H */
diff --git a/src/plugins/script/script-info.c b/src/plugins/script/script-info.c
index a65e1f3c9..52be74e37 100644
--- a/src/plugins/script/script-info.c
+++ b/src/plugins/script/script-info.c
@@ -220,7 +220,7 @@ script_info_infolist_script_script_cb (const void *pointer, void *data,
  */
 
 void
-script_info_init ()
+script_info_init (void)
 {
     /* info hooks */
     weechat_hook_info (
diff --git a/src/plugins/script/script-info.h b/src/plugins/script/script-info.h
index 74b6d8b6f..966cfe459 100644
--- a/src/plugins/script/script-info.h
+++ b/src/plugins/script/script-info.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_SCRIPT_INFO_H
 #define WEECHAT_PLUGIN_SCRIPT_INFO_H
 
-extern void script_info_init ();
+extern void script_info_init (void);
 
 #endif /* WEECHAT_PLUGIN_SCRIPT_INFO_H */
diff --git a/src/plugins/script/script-mouse.c b/src/plugins/script/script-mouse.c
index 909432596..b26392417 100644
--- a/src/plugins/script/script-mouse.c
+++ b/src/plugins/script/script-mouse.c
@@ -116,7 +116,7 @@ script_mouse_focus_chat_cb (const void *pointer, void *data,
  */
 
 int
-script_mouse_init ()
+script_mouse_init (void)
 {
     struct t_hashtable *keys;
 
@@ -160,6 +160,6 @@ script_mouse_init ()
  */
 
 void
-script_mouse_end ()
+script_mouse_end (void)
 {
 }
diff --git a/src/plugins/script/script-mouse.h b/src/plugins/script/script-mouse.h
index 6c9c99740..12137d797 100644
--- a/src/plugins/script/script-mouse.h
+++ b/src/plugins/script/script-mouse.h
@@ -20,7 +20,7 @@
 #ifndef WEECHAT_PLUGIN_SCRIPT_MOUSE_H
 #define WEECHAT_PLUGIN_SCRIPT_MOUSE_H
 
-extern int script_mouse_init ();
-extern void script_mouse_end ();
+extern int script_mouse_init (void);
+extern void script_mouse_end (void);
 
 #endif /* WEECHAT_PLUGIN_SCRIPT_MOUSE_H */
diff --git a/src/plugins/script/script-repo.c b/src/plugins/script/script-repo.c
index fffb8f414..37f13d5e4 100644
--- a/src/plugins/script/script-repo.c
+++ b/src/plugins/script/script-repo.c
@@ -375,7 +375,7 @@ script_repo_get_status_desc_for_display (struct t_script_repo *script,
  */
 
 struct t_script_repo *
-script_repo_alloc ()
+script_repo_alloc (void)
 {
     struct t_script_repo *new_script;
 
@@ -688,7 +688,7 @@ script_repo_remove (struct t_script_repo *script)
  */
 
 void
-script_repo_remove_all ()
+script_repo_remove_all (void)
 {
     while (scripts_repo)
     {
@@ -855,7 +855,7 @@ script_repo_update_status (struct t_script_repo *script)
  */
 
 void
-script_repo_update_status_all ()
+script_repo_update_status_all (void)
 {
     struct t_script_repo *ptr_script;
 
@@ -1006,7 +1006,7 @@ script_repo_filter_scripts (const char *search)
  */
 
 int
-script_repo_file_exists ()
+script_repo_file_exists (void)
 {
     char *filename;
     int rc;
@@ -1036,7 +1036,7 @@ script_repo_file_exists ()
  */
 
 int
-script_repo_file_is_uptodate ()
+script_repo_file_is_uptodate (void)
 {
     char *filename;
     struct stat st;
@@ -1599,7 +1599,7 @@ script_repo_add_to_infolist (struct t_infolist *infolist,
  */
 
 void
-script_repo_print_log ()
+script_repo_print_log (void)
 {
     struct t_script_repo *ptr_script;
 
diff --git a/src/plugins/script/script-repo.h b/src/plugins/script/script-repo.h
index c02ebab14..e6460a1ad 100644
--- a/src/plugins/script/script-repo.h
+++ b/src/plugins/script/script-repo.h
@@ -72,13 +72,13 @@ extern const char *script_repo_get_status_for_display (struct t_script_repo *scr
                                                        int collapse);
 extern const char *script_repo_get_status_desc_for_display (struct t_script_repo *script,
                                                             const char *list);
-extern void script_repo_remove_all ();
+extern void script_repo_remove_all (void);
 extern void script_repo_update_status (struct t_script_repo *script);
-extern void script_repo_update_status_all ();
+extern void script_repo_update_status_all (void);
 extern void script_repo_set_filter (const char *filter);
 extern void script_repo_filter_scripts (const char *search);
-extern int script_repo_file_exists ();
-extern int script_repo_file_is_uptodate ();
+extern int script_repo_file_exists (void);
+extern int script_repo_file_is_uptodate (void);
 extern int script_repo_file_read (int quiet);
 extern int script_repo_file_update (int quiet);
 extern struct t_hdata *script_repo_hdata_script_cb (const void *pointer,
@@ -86,6 +86,6 @@ extern struct t_hdata *script_repo_hdata_script_cb (const void *pointer,
                                                     const char *hdata_name);
 extern int script_repo_add_to_infolist (struct t_infolist *infolist,
                                         struct t_script_repo *script);
-extern void script_repo_print_log ();
+extern void script_repo_print_log (void);
 
 #endif /* WEECHAT_PLUGIN_SCRIPT_REPO_H */
diff --git a/src/plugins/script/script.c b/src/plugins/script/script.c
index 041fa632f..d1928c0e1 100644
--- a/src/plugins/script/script.c
+++ b/src/plugins/script/script.c
@@ -135,7 +135,7 @@ script_download_enabled (int display_error)
  */
 
 void
-script_get_loaded_plugins ()
+script_get_loaded_plugins (void)
 {
     int i, language;
     struct t_hdata *hdata;
@@ -163,7 +163,7 @@ script_get_loaded_plugins ()
  */
 
 void
-script_get_scripts ()
+script_get_scripts (void)
 {
     int i;
     char hdata_name[128], *filename, *ptr_base_name;
diff --git a/src/plugins/script/script.h b/src/plugins/script/script.h
index 0ec0ae42e..95a1397c5 100644
--- a/src/plugins/script/script.h
+++ b/src/plugins/script/script.h
@@ -36,7 +36,7 @@ extern struct t_hashtable *script_loaded;
 extern int script_language_search (const char *language);
 extern int script_language_search_by_extension (const char *extension);
 extern int script_download_enabled (int display_error);
-extern void script_get_loaded_plugins ();
-extern void script_get_scripts ();
+extern void script_get_loaded_plugins (void);
+extern void script_get_scripts (void);
 
 #endif /* WEECHAT_PLUGIN_SCRIPT_H */
diff --git a/src/plugins/spell/spell-bar-item.c b/src/plugins/spell/spell-bar-item.c
index 31f33d7c8..feeb48bb2 100644
--- a/src/plugins/spell/spell-bar-item.c
+++ b/src/plugins/spell/spell-bar-item.c
@@ -174,7 +174,7 @@ end:
  */
 
 void
-spell_bar_item_init ()
+spell_bar_item_init (void)
 {
     weechat_bar_item_new ("spell_dict",
                           &spell_bar_item_dict, NULL, NULL);
diff --git a/src/plugins/spell/spell-bar-item.h b/src/plugins/spell/spell-bar-item.h
index 84f65681e..e16f46ea5 100644
--- a/src/plugins/spell/spell-bar-item.h
+++ b/src/plugins/spell/spell-bar-item.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_SPELL_BAR_ITEM_H
 #define WEECHAT_PLUGIN_SPELL_BAR_ITEM_H
 
-extern void spell_bar_item_init ();
+extern void spell_bar_item_init (void);
 
 #endif /* WEECHAT_PLUGIN_SPELL_BAR_ITEM_H */
diff --git a/src/plugins/spell/spell-command.c b/src/plugins/spell/spell-command.c
index 6b194e15f..82fd51184 100644
--- a/src/plugins/spell/spell-command.c
+++ b/src/plugins/spell/spell-command.c
@@ -135,7 +135,7 @@ spell_enchant_dict_describe_cb (const char *lang_tag,
  */
 
 void
-spell_command_speller_list_dicts ()
+spell_command_speller_list_dicts (void)
 {
 #ifndef USE_ENCHANT
     char *country, *lang, *pos, *iso;
@@ -478,7 +478,7 @@ spell_command_cb (const void *pointer, void *data,
  */
 
 void
-spell_command_init ()
+spell_command_init (void)
 {
     weechat_hook_command (
         "spell",
diff --git a/src/plugins/spell/spell-command.h b/src/plugins/spell/spell-command.h
index 77ebb6959..fcc081319 100644
--- a/src/plugins/spell/spell-command.h
+++ b/src/plugins/spell/spell-command.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_SPELL_COMMAND_H
 #define WEECHAT_PLUGIN_SPELL_COMMAND_H
 
-extern void spell_command_init ();
+extern void spell_command_init (void);
 
 #endif /* WEECHAT_PLUGIN_SPELL_COMMAND_H */
diff --git a/src/plugins/spell/spell-completion.c b/src/plugins/spell/spell-completion.c
index 5b98f36ab..9ea6b4e7d 100644
--- a/src/plugins/spell/spell-completion.c
+++ b/src/plugins/spell/spell-completion.c
@@ -131,7 +131,7 @@ spell_completion_dicts_cb (const void *pointer, void *data,
  */
 
 void
-spell_completion_init ()
+spell_completion_init (void)
 {
     weechat_hook_completion ("spell_langs",
                              N_("list of all languages supported"),
diff --git a/src/plugins/spell/spell-completion.h b/src/plugins/spell/spell-completion.h
index 74bc1adfb..7d5786f80 100644
--- a/src/plugins/spell/spell-completion.h
+++ b/src/plugins/spell/spell-completion.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_SPELL_COMPLETION_H
 #define WEECHAT_PLUGIN_SPELL_COMPLETION_H
 
-extern void spell_completion_init ();
+extern void spell_completion_init (void);
 
 #endif /* WEECHAT_PLUGIN_SPELL_COMPLETION_H */
diff --git a/src/plugins/spell/spell-config.c b/src/plugins/spell/spell-config.c
index f0151f9aa..774433370 100644
--- a/src/plugins/spell/spell-config.c
+++ b/src/plugins/spell/spell-config.c
@@ -443,7 +443,7 @@ spell_config_set_dict (const char *name, const char *value)
  */
 
 int
-spell_config_init ()
+spell_config_init (void)
 {
     spell_config_file = weechat_config_new (SPELL_CONFIG_PRIO_NAME,
                                             NULL, NULL, NULL);
@@ -622,7 +622,7 @@ spell_config_init ()
  */
 
 int
-spell_config_read ()
+spell_config_read (void)
 {
     int rc;
 
@@ -641,7 +641,7 @@ spell_config_read ()
  */
 
 int
-spell_config_write ()
+spell_config_write (void)
 {
     return weechat_config_write (spell_config_file);
 }
@@ -651,7 +651,7 @@ spell_config_write ()
  */
 
 void
-spell_config_free ()
+spell_config_free (void)
 {
     weechat_config_free (spell_config_file);
     spell_config_file = NULL;
diff --git a/src/plugins/spell/spell-config.h b/src/plugins/spell/spell-config.h
index cdea2e7f9..1416f0d5c 100644
--- a/src/plugins/spell/spell-config.h
+++ b/src/plugins/spell/spell-config.h
@@ -46,9 +46,9 @@ extern int *spell_length_commands_to_check;
 
 extern struct t_config_option *spell_config_get_dict (const char *name);
 extern int spell_config_set_dict (const char *name, const char *value);
-extern int spell_config_init ();
-extern int spell_config_read ();
-extern int spell_config_write ();
-extern void spell_config_free ();
+extern int spell_config_init (void);
+extern int spell_config_read (void);
+extern int spell_config_write (void);
+extern void spell_config_free (void);
 
 #endif /* WEECHAT_PLUGIN_SPELL_CONFIG_H */
diff --git a/src/plugins/spell/spell-info.c b/src/plugins/spell/spell-info.c
index b5bbe1492..0762b7c92 100644
--- a/src/plugins/spell/spell-info.c
+++ b/src/plugins/spell/spell-info.c
@@ -80,7 +80,7 @@ spell_info_info_spell_dict_cb (const void *pointer, void *data,
  */
 
 void
-spell_info_init ()
+spell_info_init (void)
 {
     /* info hooks */
     weechat_hook_info (
diff --git a/src/plugins/spell/spell-info.h b/src/plugins/spell/spell-info.h
index eac8274af..c07e053e0 100644
--- a/src/plugins/spell/spell-info.h
+++ b/src/plugins/spell/spell-info.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_SPELL_INFO_H
 #define WEECHAT_PLUGIN_SPELL_INFO_H
 
-extern void spell_info_init ();
+extern void spell_info_init (void);
 
 #endif /* WEECHAT_PLUGIN_SPELL_INFO_H */
diff --git a/src/plugins/spell/spell-speller.c b/src/plugins/spell/spell-speller.c
index 0f7b617df..5953f60ac 100644
--- a/src/plugins/spell/spell-speller.c
+++ b/src/plugins/spell/spell-speller.c
@@ -275,7 +275,7 @@ spell_speller_remove_unused_cb (void *data,
  */
 
 void
-spell_speller_remove_unused ()
+spell_speller_remove_unused (void)
 {
     struct t_hashtable *used_spellers;
     struct t_infolist *infolist;
@@ -461,7 +461,7 @@ spell_speller_buffer_free_value_cb (struct t_hashtable *hashtable,
  */
 
 int
-spell_speller_init ()
+spell_speller_init (void)
 {
     spell_spellers = weechat_hashtable_new (32,
                                             WEECHAT_HASHTABLE_STRING,
@@ -494,7 +494,7 @@ spell_speller_init ()
  */
 
 void
-spell_speller_end ()
+spell_speller_end (void)
 {
     weechat_hashtable_free (spell_spellers);
     spell_spellers = NULL;
diff --git a/src/plugins/spell/spell-speller.h b/src/plugins/spell/spell-speller.h
index c4f99626c..802a3dcaf 100644
--- a/src/plugins/spell/spell-speller.h
+++ b/src/plugins/spell/spell-speller.h
@@ -43,9 +43,9 @@ extern EnchantDict *spell_speller_new (const char *lang);
 #else
 extern AspellSpeller *spell_speller_new (const char *lang);
 #endif /* USE_ENCHANT */
-extern void spell_speller_remove_unused ();
+extern void spell_speller_remove_unused (void);
 extern struct t_spell_speller_buffer *spell_speller_buffer_new (struct t_gui_buffer *buffer);
-extern int spell_speller_init ();
-extern void spell_speller_end ();
+extern int spell_speller_init (void);
+extern void spell_speller_end (void);
 
 #endif /* WEECHAT_PLUGIN_SPELL_SPELLER_H */
diff --git a/src/plugins/spell/spell.c b/src/plugins/spell/spell.c
index ecbba0e7e..c506eb8bf 100644
--- a/src/plugins/spell/spell.c
+++ b/src/plugins/spell/spell.c
@@ -190,7 +190,7 @@ char *spell_url_prefix[] =
  */
 
 void
-spell_warning_aspell_config ()
+spell_warning_aspell_config (void)
 {
     char *aspell_filename, *spell_filename;
 
diff --git a/src/plugins/tcl/weechat-tcl.c b/src/plugins/tcl/weechat-tcl.c
index ad690dbda..34a04a992 100644
--- a/src/plugins/tcl/weechat-tcl.c
+++ b/src/plugins/tcl/weechat-tcl.c
@@ -500,7 +500,7 @@ weechat_tcl_unload_name (const char *name)
  */
 
 void
-weechat_tcl_unload_all ()
+weechat_tcl_unload_all (void)
 {
     while (tcl_scripts)
     {
diff --git a/src/plugins/trigger/trigger-buffer.c b/src/plugins/trigger/trigger-buffer.c
index cabc37cf6..c04f8e18e 100644
--- a/src/plugins/trigger/trigger-buffer.c
+++ b/src/plugins/trigger/trigger-buffer.c
@@ -105,7 +105,7 @@ trigger_buffer_set_filter (const char *filter)
  */
 
 void
-trigger_buffer_set_title ()
+trigger_buffer_set_title (void)
 {
     const char *ptr_filter;
     char title[1024];
@@ -174,7 +174,7 @@ trigger_buffer_close_cb (const void *pointer, void *data,
  */
 
 void
-trigger_buffer_set_callbacks ()
+trigger_buffer_set_callbacks (void)
 {
     struct t_gui_buffer *ptr_buffer;
 
@@ -383,7 +383,7 @@ trigger_buffer_display_trigger (struct t_trigger *trigger,
  */
 
 void
-trigger_buffer_end ()
+trigger_buffer_end (void)
 {
     if (trigger_buffer)
     {
diff --git a/src/plugins/trigger/trigger-buffer.h b/src/plugins/trigger/trigger-buffer.h
index bfb22987d..5c2094c13 100644
--- a/src/plugins/trigger/trigger-buffer.h
+++ b/src/plugins/trigger/trigger-buffer.h
@@ -26,10 +26,10 @@ struct t_trigger_context;
 
 extern struct t_gui_buffer *trigger_buffer;
 
-extern void trigger_buffer_set_callbacks ();
+extern void trigger_buffer_set_callbacks (void);
 extern void trigger_buffer_open (const char *filter, int switch_to_buffer);
 extern int trigger_buffer_display_trigger (struct t_trigger *trigger,
                                            struct t_trigger_context *context);
-extern void trigger_buffer_end ();
+extern void trigger_buffer_end (void);
 
 #endif /* WEECHAT_PLUGIN_TRIGGER_BUFFER_H */
diff --git a/src/plugins/trigger/trigger-callback.c b/src/plugins/trigger/trigger-callback.c
index af9052bfc..6e7f650bb 100644
--- a/src/plugins/trigger/trigger-callback.c
+++ b/src/plugins/trigger/trigger-callback.c
@@ -1484,7 +1484,7 @@ end:
  */
 
 void
-trigger_callback_init ()
+trigger_callback_init (void)
 {
     trigger_callback_hashtable_options_conditions = weechat_hashtable_new (
         32,
@@ -1503,7 +1503,7 @@ trigger_callback_init ()
  */
 
 void
-trigger_callback_end ()
+trigger_callback_end (void)
 {
     if (trigger_callback_hashtable_options_conditions)
     {
diff --git a/src/plugins/trigger/trigger-callback.h b/src/plugins/trigger/trigger-callback.h
index a07ec8e08..b4b04b40a 100644
--- a/src/plugins/trigger/trigger-callback.h
+++ b/src/plugins/trigger/trigger-callback.h
@@ -150,7 +150,7 @@ extern struct t_hashtable *trigger_callback_info_hashtable_cb (const void *point
                                                                void *data,
                                                                const char *info_name,
                                                                struct t_hashtable *hashtable);
-extern void trigger_callback_init ();
-extern void trigger_callback_end ();
+extern void trigger_callback_init (void);
+extern void trigger_callback_end (void);
 
 #endif /* WEECHAT_PLUGIN_TRIGGER_CALLBACK_H */
diff --git a/src/plugins/trigger/trigger-command.c b/src/plugins/trigger/trigger-command.c
index 87e352625..e29df3703 100644
--- a/src/plugins/trigger/trigger-command.c
+++ b/src/plugins/trigger/trigger-command.c
@@ -35,7 +35,7 @@
  */
 
 void
-trigger_command_display_status ()
+trigger_command_display_status (void)
 {
     weechat_printf_date_tags (NULL, 0, "no_trigger",
                               (trigger_enabled) ?
@@ -1252,7 +1252,7 @@ end:
  */
 
 void
-trigger_command_init ()
+trigger_command_init (void)
 {
     weechat_hook_command (
         "trigger",
diff --git a/src/plugins/trigger/trigger-command.h b/src/plugins/trigger/trigger-command.h
index b5b0f35d8..3d3c73ad8 100644
--- a/src/plugins/trigger/trigger-command.h
+++ b/src/plugins/trigger/trigger-command.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_TRIGGER_COMMAND_H
 #define WEECHAT_PLUGIN_TRIGGER_COMMAND_H
 
-extern void trigger_command_init ();
+extern void trigger_command_init (void);
 
 #endif /* WEECHAT_PLUGIN_TRIGGER_COMMAND_H */
diff --git a/src/plugins/trigger/trigger-completion.c b/src/plugins/trigger/trigger-completion.c
index 64620025a..77cc97170 100644
--- a/src/plugins/trigger/trigger-completion.c
+++ b/src/plugins/trigger/trigger-completion.c
@@ -604,7 +604,7 @@ trigger_completion_add_arguments_cb (const void *pointer, void *data,
  */
 
 void
-trigger_completion_init ()
+trigger_completion_init (void)
 {
     weechat_hook_completion ("trigger_names",
                              N_("triggers"),
diff --git a/src/plugins/trigger/trigger-completion.h b/src/plugins/trigger/trigger-completion.h
index 41d72a625..30e17fd8c 100644
--- a/src/plugins/trigger/trigger-completion.h
+++ b/src/plugins/trigger/trigger-completion.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_TRIGGER_COMPLETION_H
 #define WEECHAT_PLUGIN_TRIGGER_COMPLETION_H
 
-extern void trigger_completion_init ();
+extern void trigger_completion_init (void);
 
 #endif /* WEECHAT_PLUGIN_TRIGGER_COMPLETION_H */
diff --git a/src/plugins/trigger/trigger-config.c b/src/plugins/trigger/trigger-config.c
index 92a4da55a..a1b6825a5 100644
--- a/src/plugins/trigger/trigger-config.c
+++ b/src/plugins/trigger/trigger-config.c
@@ -485,7 +485,7 @@ trigger_config_create_option_temp (struct t_trigger *temp_trigger,
  */
 
 void
-trigger_config_use_temp_triggers ()
+trigger_config_use_temp_triggers (void)
 {
     struct t_trigger *ptr_temp_trigger, *next_temp_trigger;
     int i, num_options_ok;
@@ -684,7 +684,7 @@ trigger_config_reload_cb (const void *pointer, void *data,
  */
 
 int
-trigger_config_init ()
+trigger_config_init (void)
 {
     trigger_config_file = weechat_config_new (
         TRIGGER_CONFIG_PRIO_NAME,
@@ -799,7 +799,7 @@ trigger_config_init ()
  */
 
 int
-trigger_config_read ()
+trigger_config_read (void)
 {
     int rc;
 
@@ -815,7 +815,7 @@ trigger_config_read ()
  */
 
 int
-trigger_config_write ()
+trigger_config_write (void)
 {
     return weechat_config_write (trigger_config_file);
 }
@@ -825,7 +825,7 @@ trigger_config_write ()
  */
 
 void
-trigger_config_free ()
+trigger_config_free (void)
 {
     weechat_config_free (trigger_config_file);
     trigger_config_file = NULL;
diff --git a/src/plugins/trigger/trigger-config.h b/src/plugins/trigger/trigger-config.h
index c107d886e..d34d03ab5 100644
--- a/src/plugins/trigger/trigger-config.h
+++ b/src/plugins/trigger/trigger-config.h
@@ -47,9 +47,9 @@ extern char *trigger_config_default_list[][1 + TRIGGER_NUM_OPTIONS];
 extern struct t_config_option *trigger_config_create_trigger_option (const char *trigger_name,
                                                                      int index_option,
                                                                      const char *value);
-extern int trigger_config_init ();
-extern int trigger_config_read ();
-extern int trigger_config_write ();
-extern void trigger_config_free ();
+extern int trigger_config_init (void);
+extern int trigger_config_read (void);
+extern int trigger_config_write (void);
+extern void trigger_config_free (void);
 
 #endif /* WEECHAT_PLUGIN_TRIGGER_CONFIG_H */
diff --git a/src/plugins/trigger/trigger.c b/src/plugins/trigger/trigger.c
index 868695fdd..77c6481d7 100644
--- a/src/plugins/trigger/trigger.c
+++ b/src/plugins/trigger/trigger.c
@@ -1101,7 +1101,7 @@ trigger_new (const char *name, const char *enabled, const char *hook,
  */
 
 void
-trigger_create_default ()
+trigger_create_default (void)
 {
     int i;
 
@@ -1244,7 +1244,7 @@ trigger_free (struct t_trigger *trigger)
  */
 
 void
-trigger_free_all ()
+trigger_free_all (void)
 {
     while (triggers)
     {
@@ -1257,7 +1257,7 @@ trigger_free_all ()
  */
 
 void
-trigger_print_log ()
+trigger_print_log (void)
 {
     struct t_trigger *ptr_trigger;
     int i;
diff --git a/src/plugins/trigger/trigger.h b/src/plugins/trigger/trigger.h
index 71410184c..b9bfb2f15 100644
--- a/src/plugins/trigger/trigger.h
+++ b/src/plugins/trigger/trigger.h
@@ -178,11 +178,11 @@ extern struct t_trigger *trigger_new (const char *name,
                                       const char *command,
                                       const char *return_code,
                                       const char *post_action);
-extern void trigger_create_default ();
+extern void trigger_create_default (void);
 extern int trigger_rename (struct t_trigger *trigger, const char *name);
 extern struct t_trigger *trigger_copy (struct t_trigger *trigger,
                                        const char *name);
 extern void trigger_free (struct t_trigger *trigger);
-extern void trigger_free_all ();
+extern void trigger_free_all (void);
 
 #endif /* WEECHAT_PLUGIN_TRIGGER_H */
diff --git a/src/plugins/typing/typing-bar-item.c b/src/plugins/typing/typing-bar-item.c
index 607693783..e821498a9 100644
--- a/src/plugins/typing/typing-bar-item.c
+++ b/src/plugins/typing/typing-bar-item.c
@@ -124,7 +124,7 @@ typing_bar_item_typing (const void *pointer, void *data,
  */
 
 void
-typing_bar_item_init ()
+typing_bar_item_init (void)
 {
     weechat_bar_item_new (TYPING_BAR_ITEM_NAME,
                           &typing_bar_item_typing, NULL, NULL);
diff --git a/src/plugins/typing/typing-bar-item.h b/src/plugins/typing/typing-bar-item.h
index a036026dd..c08d37423 100644
--- a/src/plugins/typing/typing-bar-item.h
+++ b/src/plugins/typing/typing-bar-item.h
@@ -22,6 +22,6 @@
 
 #define TYPING_BAR_ITEM_NAME "typing"
 
-extern void typing_bar_item_init ();
+extern void typing_bar_item_init (void);
 
 #endif /* WEECHAT_PLUGIN_TYPING_BAR_ITEM_H */
diff --git a/src/plugins/typing/typing-config.c b/src/plugins/typing/typing-config.c
index 86e82145f..4cb3d541b 100644
--- a/src/plugins/typing/typing-config.c
+++ b/src/plugins/typing/typing-config.c
@@ -110,7 +110,7 @@ typing_config_change_item_max_length (const void *pointer, void *data,
  */
 
 int
-typing_config_init ()
+typing_config_init (void)
 {
     typing_config_file = weechat_config_new (
         TYPING_CONFIG_PRIO_NAME,
@@ -195,7 +195,7 @@ typing_config_init ()
  */
 
 int
-typing_config_read ()
+typing_config_read (void)
 {
     return weechat_config_read (typing_config_file);
 }
@@ -205,7 +205,7 @@ typing_config_read ()
  */
 
 int
-typing_config_write ()
+typing_config_write (void)
 {
     return weechat_config_write (typing_config_file);
 }
@@ -215,7 +215,7 @@ typing_config_write ()
  */
 
 void
-typing_config_free ()
+typing_config_free (void)
 {
     weechat_config_free (typing_config_file);
     typing_config_file = NULL;
diff --git a/src/plugins/typing/typing-config.h b/src/plugins/typing/typing-config.h
index 0f37a0304..381ac51e6 100644
--- a/src/plugins/typing/typing-config.h
+++ b/src/plugins/typing/typing-config.h
@@ -31,9 +31,9 @@ extern struct t_config_option *typing_config_look_enabled_self;
 extern struct t_config_option *typing_config_look_input_min_chars;
 extern struct t_config_option *typing_config_look_item_max_length;
 
-extern int typing_config_init ();
-extern int typing_config_read ();
-extern int typing_config_write ();
-extern void typing_config_free ();
+extern int typing_config_init (void);
+extern int typing_config_read (void);
+extern int typing_config_write (void);
+extern void typing_config_free (void);
 
 #endif /* WEECHAT_PLUGIN_TYPING_CONFIG_H */
diff --git a/src/plugins/typing/typing-status.c b/src/plugins/typing/typing-status.c
index 9f75e06cf..8d39277ac 100644
--- a/src/plugins/typing/typing-status.c
+++ b/src/plugins/typing/typing-status.c
@@ -349,7 +349,7 @@ typing_status_nick_remove (struct t_gui_buffer *buffer, const char *nick)
  */
 
 void
-typing_status_end ()
+typing_status_end (void)
 {
     if (typing_status_self)
     {
diff --git a/src/plugins/typing/typing-status.h b/src/plugins/typing/typing-status.h
index 2aa192742..9b02fbce4 100644
--- a/src/plugins/typing/typing-status.h
+++ b/src/plugins/typing/typing-status.h
@@ -57,6 +57,6 @@ extern struct t_typing_status *typing_status_nick_search (struct t_gui_buffer *b
                                                           const char *nick);
 extern void typing_status_nick_remove (struct t_gui_buffer *buffer,
                                        const char *nick);
-extern void typing_status_end ();
+extern void typing_status_end (void);
 
 #endif /* WEECHAT_PLUGIN_TYPING_STATUS_H */
diff --git a/src/plugins/typing/typing.c b/src/plugins/typing/typing.c
index 5cf83e8dc..b054280e4 100644
--- a/src/plugins/typing/typing.c
+++ b/src/plugins/typing/typing.c
@@ -478,7 +478,7 @@ typing_typing_reset_buffer_signal_cb (const void *pointer, void *data,
  */
 
 void
-typing_setup_hooks ()
+typing_setup_hooks (void)
 {
     if (weechat_config_boolean (typing_config_look_enabled_self))
     {
@@ -580,7 +580,7 @@ typing_setup_hooks ()
  */
 
 void
-typing_remove_hooks ()
+typing_remove_hooks (void)
 {
     if (typing_signal_buffer_closing)
     {
diff --git a/src/plugins/typing/typing.h b/src/plugins/typing/typing.h
index a9de05c98..83b495cbb 100644
--- a/src/plugins/typing/typing.h
+++ b/src/plugins/typing/typing.h
@@ -40,6 +40,6 @@ extern struct t_typing *typing_list;
 
 extern struct t_weechat_plugin *weechat_typing_plugin;
 
-extern void typing_setup_hooks ();
+extern void typing_setup_hooks (void);
 
 #endif /* WEECHAT_PLUGIN_TYPING_H */
diff --git a/src/plugins/weechat-plugin.h b/src/plugins/weechat-plugin.h
index 535d62a7e..162ca5110 100644
--- a/src/plugins/weechat-plugin.h
+++ b/src/plugins/weechat-plugin.h
@@ -467,7 +467,7 @@ struct t_weechat_plugin
     int (*util_version_number) (const char *version);
 
     /* sorted lists */
-    struct t_weelist *(*list_new) ();
+    struct t_weelist *(*list_new) (void);
     struct t_weelist_item *(*list_add) (struct t_weelist *weelist,
                                         const char *data,
                                         const char *where,
@@ -998,7 +998,7 @@ struct t_weechat_plugin
                                               const void *close_callback_pointer,
                                               void *close_callback_data);
     struct t_gui_buffer *(*buffer_search) (const char *plugin, const char *name);
-    struct t_gui_buffer *(*buffer_search_main) ();
+    struct t_gui_buffer *(*buffer_search_main) (void);
     void (*buffer_clear) (struct t_gui_buffer *buffer);
     void (*buffer_close) (struct t_gui_buffer *buffer);
     void (*buffer_merge) (struct t_gui_buffer *buffer,
diff --git a/src/plugins/xfer/xfer-buffer.c b/src/plugins/xfer/xfer-buffer.c
index 12a554564..c356ac38e 100644
--- a/src/plugins/xfer/xfer-buffer.c
+++ b/src/plugins/xfer/xfer-buffer.c
@@ -346,7 +346,7 @@ xfer_buffer_close_cb (const void *pointer, void *data,
  */
 
 void
-xfer_buffer_open ()
+xfer_buffer_open (void)
 {
     struct t_hashtable *buffer_props;
 
diff --git a/src/plugins/xfer/xfer-buffer.h b/src/plugins/xfer/xfer-buffer.h
index 67014c9af..11c4bcfbf 100644
--- a/src/plugins/xfer/xfer-buffer.h
+++ b/src/plugins/xfer/xfer-buffer.h
@@ -31,6 +31,6 @@ extern int xfer_buffer_input_cb (const void *pointer, void *data,
                                  const char *input_data);
 extern int xfer_buffer_close_cb (const void *pointer, void *data,
                                  struct t_gui_buffer *buffer);
-extern void xfer_buffer_open ();
+extern void xfer_buffer_open (void);
 
 #endif /* WEECHAT_PLUGIN_XFER_BUFFER_H */
diff --git a/src/plugins/xfer/xfer-command.c b/src/plugins/xfer/xfer-command.c
index c92b5d448..9b74c9e0e 100644
--- a/src/plugins/xfer/xfer-command.c
+++ b/src/plugins/xfer/xfer-command.c
@@ -252,7 +252,7 @@ xfer_command_xfer (const void *pointer, void *data,
  */
 
 void
-xfer_command_init ()
+xfer_command_init (void)
 {
     struct t_hook *ptr_hook;
 
diff --git a/src/plugins/xfer/xfer-command.h b/src/plugins/xfer/xfer-command.h
index d4dc8e6f7..fc1cd556e 100644
--- a/src/plugins/xfer/xfer-command.h
+++ b/src/plugins/xfer/xfer-command.h
@@ -22,6 +22,6 @@
 
 #define XFER_COMMAND_KEEP_SPACES weechat_hook_set (ptr_hook, "keep_spaces_right", "1")
 
-extern void xfer_command_init ();
+extern void xfer_command_init (void);
 
 #endif /* WEECHAT_PLUGIN_XFER_COMMAND_H */
diff --git a/src/plugins/xfer/xfer-completion.c b/src/plugins/xfer/xfer-completion.c
index 8e57aad99..5b8f21b59 100644
--- a/src/plugins/xfer/xfer-completion.c
+++ b/src/plugins/xfer/xfer-completion.c
@@ -68,7 +68,7 @@ xfer_completion_nick_cb (const void *pointer, void *data,
  */
 
 void
-xfer_completion_init ()
+xfer_completion_init (void)
 {
     weechat_hook_completion ("nick",
                              N_("nicks of DCC chat"),
diff --git a/src/plugins/xfer/xfer-completion.h b/src/plugins/xfer/xfer-completion.h
index 2720e6864..9928b4ecc 100644
--- a/src/plugins/xfer/xfer-completion.h
+++ b/src/plugins/xfer/xfer-completion.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_XFER_COMPLETION_H
 #define WEECHAT_PLUGIN_XFER_COMPLETION_H
 
-extern void xfer_completion_init ();
+extern void xfer_completion_init (void);
 
 #endif /* WEECHAT_PLUGIN_XFER_COMPLETION_H */
diff --git a/src/plugins/xfer/xfer-config.c b/src/plugins/xfer/xfer-config.c
index 7a09f0df5..7b078a83d 100644
--- a/src/plugins/xfer/xfer-config.c
+++ b/src/plugins/xfer/xfer-config.c
@@ -119,7 +119,7 @@ xfer_config_reload (const void *pointer, void *data,
  */
 
 int
-xfer_config_init ()
+xfer_config_init (void)
 {
     xfer_config_file = weechat_config_new (XFER_CONFIG_PRIO_NAME,
                                            &xfer_config_reload, NULL, NULL);
@@ -418,7 +418,7 @@ xfer_config_init ()
  */
 
 int
-xfer_config_read ()
+xfer_config_read (void)
 {
     return weechat_config_read (xfer_config_file);
 }
@@ -428,7 +428,7 @@ xfer_config_read ()
  */
 
 int
-xfer_config_write ()
+xfer_config_write (void)
 {
     return weechat_config_write (xfer_config_file);
 }
diff --git a/src/plugins/xfer/xfer-config.h b/src/plugins/xfer/xfer-config.h
index 691db4b63..1d0270a8c 100644
--- a/src/plugins/xfer/xfer-config.h
+++ b/src/plugins/xfer/xfer-config.h
@@ -57,8 +57,8 @@ extern struct t_config_option *xfer_config_file_download_temporary_suffix;
 extern struct t_config_option *xfer_config_file_upload_path;
 extern struct t_config_option *xfer_config_file_use_nick_in_filename;
 
-extern int xfer_config_init ();
-extern int xfer_config_read ();
-extern int xfer_config_write ();
+extern int xfer_config_init (void);
+extern int xfer_config_read (void);
+extern int xfer_config_write (void);
 
 #endif /* WEECHAT_PLUGIN_XFER_CONFIG_H */
diff --git a/src/plugins/xfer/xfer-info.c b/src/plugins/xfer/xfer-info.c
index e31dc9020..cffad876c 100644
--- a/src/plugins/xfer/xfer-info.c
+++ b/src/plugins/xfer/xfer-info.c
@@ -84,7 +84,7 @@ xfer_info_infolist_xfer_cb (const void *pointer, void *data,
  */
 
 void
-xfer_info_init ()
+xfer_info_init (void)
 {
     weechat_hook_infolist (
         "xfer", N_("list of xfer"),
diff --git a/src/plugins/xfer/xfer-info.h b/src/plugins/xfer/xfer-info.h
index 629725dbb..d0e9e3c7c 100644
--- a/src/plugins/xfer/xfer-info.h
+++ b/src/plugins/xfer/xfer-info.h
@@ -20,6 +20,6 @@
 #ifndef WEECHAT_PLUGIN_XFER_INFO_H
 #define WEECHAT_PLUGIN_XFER_INFO_H
 
-extern void xfer_info_init ();
+extern void xfer_info_init (void);
 
 #endif /* WEECHAT_PLUGIN_XFER_INFO_H */
diff --git a/src/plugins/xfer/xfer-upgrade.c b/src/plugins/xfer/xfer-upgrade.c
index 462a964b7..f2c44c61a 100644
--- a/src/plugins/xfer/xfer-upgrade.c
+++ b/src/plugins/xfer/xfer-upgrade.c
@@ -54,7 +54,7 @@ xfer_upgrade_save_xfers (struct t_upgrade_file *upgrade_file)
  */
 
 int
-xfer_upgrade_save ()
+xfer_upgrade_save (void)
 {
     int rc;
     struct t_upgrade_file *upgrade_file;
@@ -77,7 +77,7 @@ xfer_upgrade_save ()
  */
 
 void
-xfer_upgrade_set_buffer_callbacks ()
+xfer_upgrade_set_buffer_callbacks (void)
 {
     struct t_infolist *infolist;
     struct t_gui_buffer *ptr_buffer;
@@ -144,7 +144,7 @@ xfer_upgrade_read_cb (const void *pointer, void *data,
  */
 
 int
-xfer_upgrade_load ()
+xfer_upgrade_load (void)
 {
     int rc;
     struct t_upgrade_file *upgrade_file;
diff --git a/src/plugins/xfer/xfer-upgrade.h b/src/plugins/xfer/xfer-upgrade.h
index b264b8c41..9ab386380 100644
--- a/src/plugins/xfer/xfer-upgrade.h
+++ b/src/plugins/xfer/xfer-upgrade.h
@@ -29,7 +29,7 @@ enum t_xfer_upgrade_type
     XFER_UPGRADE_TYPE_XFER = 0,
 };
 
-extern int xfer_upgrade_save ();
-extern int xfer_upgrade_load ();
+extern int xfer_upgrade_save (void);
+extern int xfer_upgrade_load (void);
 
 #endif /* WEECHAT_PLUGIN_XFER_UPGRADE_H */
diff --git a/src/plugins/xfer/xfer.c b/src/plugins/xfer/xfer.c
index c7dd7d530..09e440029 100644
--- a/src/plugins/xfer/xfer.c
+++ b/src/plugins/xfer/xfer.c
@@ -80,7 +80,7 @@ struct t_xfer *xfer_list = NULL;       /* list of files/chats               */
 struct t_xfer *last_xfer = NULL;       /* last file/chat in list            */
 int xfer_count = 0;                    /* number of xfer                    */
 
-void xfer_disconnect_all ();
+void xfer_disconnect_all (void);
 
 
 /*
@@ -165,7 +165,7 @@ xfer_signal_upgrade_cb (const void *pointer, void *data,
  */
 
 void
-xfer_create_directories ()
+xfer_create_directories (void)
 {
     char *path;
     struct t_hashtable *options;
@@ -430,7 +430,7 @@ xfer_close (struct t_xfer *xfer, enum t_xfer_status status)
  */
 
 void
-xfer_disconnect_all ()
+xfer_disconnect_all (void)
 {
     struct t_xfer *ptr_xfer;
 
@@ -509,7 +509,7 @@ xfer_send_signal (struct t_xfer *xfer, const char *signal)
  */
 
 struct t_xfer *
-xfer_alloc ()
+xfer_alloc (void)
 {
     struct t_xfer *new_xfer;
     time_t time_now;
@@ -977,7 +977,7 @@ xfer_free (struct t_xfer *xfer)
  */
 
 void
-xfer_free_all ()
+xfer_free_all (void)
 {
     while (xfer_list)
     {
@@ -1707,7 +1707,7 @@ xfer_add_to_infolist (struct t_infolist *infolist, struct t_xfer *xfer)
  */
 
 void
-xfer_print_log ()
+xfer_print_log (void)
 {
     struct t_xfer *ptr_xfer;