diff --git a/src/core/core-config-file.c b/src/core/core-config-file.c
index 1d313074f..9d2def76d 100644
--- a/src/core/core-config-file.c
+++ b/src/core/core-config-file.c
@@ -705,7 +705,8 @@ config_file_new_option (struct t_config_file *config_file,
 {
     struct t_config_option *new_option;
     int var_type, int_value, argc, i, index_value, number;
-    char *pos, *option_name, *parent_name;
+    const char *pos;
+    char *option_name, *parent_name;
 
     new_option = NULL;
     option_name = NULL;
diff --git a/src/core/core-config.c b/src/core/core-config.c
index 55e17512f..3cb1ae0c9 100644
--- a/src/core/core-config.c
+++ b/src/core/core-config.c
@@ -1709,7 +1709,7 @@ config_weechat_update_cb (const void *pointer, void *data,
                           int version_read,
                           struct t_hashtable *data_read)
 {
-    const char *ptr_config, *ptr_section, *ptr_option, *ptr_value;
+    const char *ptr_config, *ptr_section, *ptr_option, *ptr_value, *pos_option;
     char *new_commands[][2] = {
         /* old command, new command */
         { "/input jump_smart", "/buffer jump smart" },
@@ -1739,7 +1739,7 @@ config_weechat_update_cb (const void *pointer, void *data,
         { "number_desc" "-buffer.number" },
         { NULL, NULL },
     };
-    char *new_option, *new_value, *pos_option;
+    char *new_option, *new_value;
     int changes, i;
 
     /* make C compiler happy */
@@ -2262,7 +2262,8 @@ config_weechat_proxy_read_cb (const void *pointer, void *data,
                               struct t_config_section *section,
                               const char *option_name, const char *value)
 {
-    char *pos_option, *proxy_name;
+    const char *pos_option;
+    char *proxy_name;
     struct t_proxy *ptr_temp_proxy;
     int index_option;
 
@@ -2341,7 +2342,8 @@ config_weechat_bar_read_cb (const void *pointer, void *data,
                             struct t_config_section *section,
                             const char *option_name, const char *value)
 {
-    char *pos_option, *bar_name;
+    const char *pos_option;
+    char *bar_name;
     struct t_gui_bar *ptr_temp_bar;
     int index_option;
 
@@ -2421,7 +2423,8 @@ config_weechat_custom_bar_item_read_cb (const void *pointer, void *data,
                                         struct t_config_section *section,
                                         const char *option_name, const char *value)
 {
-    char *pos_option, *item_name;
+    const char *pos_option;
+    char *item_name;
     struct t_gui_bar_item_custom *ptr_temp_item;
     int index_option;
 
@@ -2512,7 +2515,8 @@ config_weechat_layout_read_cb (const void *pointer, void *data,
                                const char *option_name, const char *value)
 {
     int argc, force_current_layout, number1, number2, number3, number4;
-    char **argv, *pos, *layout_name;
+    const char *pos;
+    char **argv, *layout_name;
     const char *ptr_option_name;
     struct t_gui_layout *ptr_layout;
     struct t_gui_layout_window *parent;
diff --git a/src/core/core-eval.c b/src/core/core-eval.c
index 071ee51d4..cf109bddc 100644
--- a/src/core/core-eval.c
+++ b/src/core/core-eval.c
@@ -508,7 +508,8 @@ eval_string_repeat (const char *text)
 char *
 eval_string_split (const char *text)
 {
-    char *pos, *pos2, *pos3, *str_number, *separators, **items, *value;
+    const char *pos, *pos2, *pos3;
+    char *str_number, *separators, **items, *value;
     char str_value[32], *str_flags, **list_flags, *strip_items, **ptr_flag;
     int num_items, count_items, random_item, flags, max_items;
     long number;
@@ -655,7 +656,8 @@ end:
 char *
 eval_string_split_shell (const char *text)
 {
-    char *pos, *str_number, **items, *value, str_value[32];
+    const char *pos;
+    char *str_number, **items, *value, str_value[32];
     int num_items, count_items, random_item;
     long number;
 
@@ -1046,7 +1048,8 @@ eval_string_if (const char *text, struct t_eval_context *eval_context)
 char *
 eval_string_random (const char *text)
 {
-    char *pos, *tmp, result[128];
+    const char *pos;
+    char *tmp, result[128];
     long long min_number, max_number;
 
     if (!text || !text[0])
@@ -1112,7 +1115,8 @@ eval_string_translate (const char *text)
 void
 eval_string_define (const char *text, struct t_eval_context *eval_context)
 {
-    char *pos, *name;
+    const char *pos;
+    char *name;
 
     pos = strchr (text, ',');
     if (!pos)
@@ -1139,7 +1143,8 @@ eval_hdata_count (const char *text, struct t_eval_context *eval_context)
     struct t_hdata *hdata;
     unsigned long ptr_value;
     void *pointer;
-    char *pos1, *pos2, *value, *hdata_name, *pointer_name, str_count[64];
+    const char *pos1, *pos2;
+    char *value, *hdata_name, *pointer_name, str_count[64];
     int rc, count;
 
     value = NULL;
@@ -1211,8 +1216,8 @@ char *
 eval_hdata_get_value (struct t_hdata *hdata, void *pointer, const char *path,
                       struct t_eval_context *eval_context)
 {
-    char *value, *var_name, str_value[128], *pos, *property;
-    const char *ptr_value, *hdata_name, *ptr_var_name, *pos_open_paren;
+    char *value, *var_name, str_value[128], *property;
+    const char *ptr_value, *hdata_name, *ptr_var_name, *pos, *pos_open_paren;
     int type, debug_id;
     struct t_hashtable *hashtable;
 
@@ -1539,8 +1544,8 @@ eval_syntax_highlight_add_markers (const char *prefix, const char *text,
 char *
 eval_syntax_highlight_colorize (const char *value)
 {
-    const char *ptr_value;
-    char **result, *pos;
+    const char *ptr_value, *pos;
+    char **result;
     int color;
 
     if (!value)
diff --git a/src/core/core-hdata.c b/src/core/core-hdata.c
index d75983afc..3e7bc2041 100644
--- a/src/core/core-hdata.c
+++ b/src/core/core-hdata.c
@@ -688,7 +688,8 @@ hdata_count (struct t_hdata *hdata, void *pointer)
 void
 hdata_get_index_and_name (const char *name, int *index, const char **ptr_name)
 {
-    char *pos, *str_index;
+    const char *pos;
+    char *str_index;
     int number;
 
     if (index)
diff --git a/src/core/core-input.c b/src/core/core-input.c
index 147d425c4..f731f454c 100644
--- a/src/core/core-input.c
+++ b/src/core/core-input.c
@@ -242,8 +242,8 @@ int
 input_data (struct t_gui_buffer *buffer, const char *data,
             const char *commands_allowed, int split_newline, int user_data)
 {
-    char *pos, str_buffer[128], *new_data, *buffer_full_name;
-    const char *ptr_data, *ptr_data_for_buffer;
+    const char *ptr_data_for_buffer;
+    char *pos, str_buffer[128], *new_data, *buffer_full_name, *ptr_data;
     int first_command, rc;
 
     if (!buffer || !gui_buffer_valid (buffer) || !data)
@@ -272,8 +272,13 @@ input_data (struct t_gui_buffer *buffer, const char *data,
     if (data[0] && new_data && !new_data[0])
         goto end;
 
+    if (!new_data)
+        new_data = strdup (data);
+    if (!new_data)
+        goto end;
+
     first_command = 1;
-    ptr_data = (new_data) ? new_data : data;
+    ptr_data = new_data;
     while (ptr_data)
     {
         /*
diff --git a/src/core/core-string.c b/src/core/core-string.c
index 05c469962..1e5156260 100644
--- a/src/core/core-string.c
+++ b/src/core/core-string.c
@@ -1686,9 +1686,8 @@ string_mask_to_regex (const char *mask)
 const char *
 string_regex_flags (const char *regex, int default_flags, int *flags)
 {
-    const char *ptr_regex, *ptr_flags;
+    const char *ptr_regex, *ptr_flags, *pos;
     int set_flag, flag;
-    char *pos;
 
     if (flags)
         *flags = default_flags;
@@ -2966,8 +2965,9 @@ char **
 string_split_command (const char *command, char separator)
 {
     int nb_substr, arr_idx, str_idx, type;
+    const char *p;
     char **array, **array2;
-    char *buffer, *p;
+    char *buffer;
     const char *ptr;
 
     if (!command || !command[0])
@@ -4138,8 +4138,7 @@ string_is_command_char (const char *string)
 const char *
 string_input_for_buffer (const char *string)
 {
-    char *pos_slash, *pos_space, *pos_newline;
-    const char *next_char;
+    const char *pos_slash, *pos_space, *pos_newline, *next_char;
 
     if (!string)
         return NULL;
@@ -4476,7 +4475,8 @@ string_get_priority_and_name (const char *string,
                               int *priority, const char **name,
                               int default_priority)
 {
-    char *pos, *str_priority;
+    const char *pos;
+    char *str_priority;
     int number;
 
     if (priority)
diff --git a/src/core/core-util.c b/src/core/core-util.c
index 9332d33da..f03dbfdc5 100644
--- a/src/core/core-util.c
+++ b/src/core/core-util.c
@@ -416,8 +416,8 @@ util_strftimeval (char *string, int max, const char *format, struct timeval *tv)
 int
 util_parse_time (const char *datetime, struct timeval *tv)
 {
-    char *string, *pos, *pos2, *pos_colon, *pos_hyphen, *pos_dot;
-    char str_usec[16], str_date[128];
+    const char *pos_colon, *pos_hyphen, *pos_dot;
+    char *pos, *pos2, *string, str_usec[16], str_date[128];
     struct tm tm_date, tm_date_gm, tm_date_local, *local_time;
     time_t time_now, time_gm, time_local;
     long long value;
diff --git a/src/core/hook/hook-command.c b/src/core/hook/hook-command.c
index 473c243b8..afef729e0 100644
--- a/src/core/hook/hook-command.c
+++ b/src/core/hook/hook-command.c
@@ -597,8 +597,8 @@ hook_command_exec (struct t_gui_buffer *buffer, int any_plugin,
     struct t_hook *hook_plugin, *hook_other_plugin, *hook_other_plugin2;
     struct t_hook *hook_incomplete_command;
     struct t_hook_exec_cb hook_exec_cb;
-    char **argv, **argv_eol, *command_name, *pos;
-    const char *ptr_string;
+    char **argv, **argv_eol, *command_name;
+    const char *ptr_string, *pos;
     int argc, rc, length_command_name, allow_incomplete_commands;
     int count_other_plugin, count_incomplete_commands, flags;
 
diff --git a/src/core/hook/hook-signal.c b/src/core/hook/hook-signal.c
index 509e987cf..3268f6e46 100644
--- a/src/core/hook/hook-signal.c
+++ b/src/core/hook/hook-signal.c
@@ -132,7 +132,8 @@ void
 hook_signal_extract_flags (const char *signal, const char **ptr_signal,
                            int *stop_on_error, int *ignore_eat)
 {
-    char *pos, *str_flags, **flags;
+    const char *pos;
+    char *str_flags, **flags;
     int i, num_flags;
 
     if (!signal || !ptr_signal || !stop_on_error || !ignore_eat)
diff --git a/src/gui/gui-bar-item-custom.c b/src/gui/gui-bar-item-custom.c
index 13744ec77..ec468b8ad 100644
--- a/src/gui/gui-bar-item-custom.c
+++ b/src/gui/gui-bar-item-custom.c
@@ -138,7 +138,8 @@ gui_bar_item_custom_search (const char *item_name)
 struct t_gui_bar_item_custom *
 gui_bar_item_custom_search_with_option_name (const char *option_name)
 {
-    char *item_name, *pos_option;
+    const char *pos_option;
+    char *item_name;
     struct t_gui_bar_item_custom *ptr_item;
 
     if (!option_name)
diff --git a/src/gui/gui-bar.c b/src/gui/gui-bar.c
index d03305f16..90ca17c8b 100644
--- a/src/gui/gui-bar.c
+++ b/src/gui/gui-bar.c
@@ -515,7 +515,8 @@ gui_bar_search (const char *name)
 struct t_gui_bar *
 gui_bar_search_with_option_name (const char *option_name)
 {
-    char *bar_name, *pos_option;
+    const char *pos_option;
+    char *bar_name;
     struct t_gui_bar *ptr_bar;
 
     if (!option_name)
diff --git a/src/gui/gui-chat.c b/src/gui/gui-chat.c
index 20f2337bd..3815b5635 100644
--- a/src/gui/gui-chat.c
+++ b/src/gui/gui-chat.c
@@ -118,8 +118,8 @@ gui_chat_init (void)
 void
 gui_chat_prefix_build (void)
 {
-    const char *ptr_prefix;
-    char prefix[512], *pos_color;
+    const char *ptr_prefix, *pos_color;
+    char prefix[512];
     int prefix_color[GUI_CHAT_NUM_PREFIXES] =
         { GUI_COLOR_CHAT_PREFIX_ERROR, GUI_COLOR_CHAT_PREFIX_NETWORK,
           GUI_COLOR_CHAT_PREFIX_ACTION, GUI_COLOR_CHAT_PREFIX_JOIN,
diff --git a/src/gui/gui-color.c b/src/gui/gui-color.c
index 59cfaaef0..d0fbdd46b 100644
--- a/src/gui/gui-color.c
+++ b/src/gui/gui-color.c
@@ -254,8 +254,8 @@ gui_color_get_custom (const char *color_name)
     static char color[32][96];
     static int index_color = 0;
     char color_fg[32], color_bg[32];
-    char *pos_delim, *str_fg, *pos_bg, *error, *color_attr;
-    const char *ptr_color_name;
+    char *str_fg, *error, *color_attr;
+    const char *ptr_color_name, *pos_delim, *pos_bg;
 
     /* attribute or other color name (GUI dependent) */
     index_color = (index_color + 1) % 32;
diff --git a/src/gui/gui-filter.c b/src/gui/gui-filter.c
index 469665858..0fdee54fc 100644
--- a/src/gui/gui-filter.c
+++ b/src/gui/gui-filter.c
@@ -366,8 +366,8 @@ gui_filter_new (int enabled, const char *name, const char *buffer_name,
 {
     struct t_gui_filter *new_filter;
     regex_t *regex1, *regex2;
-    char *pos_tab, *regex_prefix, buf[512], str_error[1024];
-    const char *ptr_start_regex, *pos_regex_message;
+    char *regex_prefix, buf[512], str_error[1024];
+    const char *ptr_start_regex, *pos_regex_message, *pos_tab;
     int rc;
 
     if (!name || !buffer_name || !tags || !regex)
diff --git a/src/gui/gui-key.c b/src/gui/gui-key.c
index 187ba0134..0eb51a613 100644
--- a/src/gui/gui-key.c
+++ b/src/gui/gui-key.c
@@ -1076,7 +1076,7 @@ gui_key_set_area_type_name (const char *area,
                             int *area_type, char **area_name)
 {
     int focus, length;
-    char *pos_end;
+    const char *pos_end;
 
     for (focus = 0; focus < GUI_KEY_NUM_FOCUS; focus++)
     {
diff --git a/src/plugins/plugin-api-info.c b/src/plugins/plugin-api-info.c
index 0a399da5d..0b16e69d8 100644
--- a/src/plugins/plugin-api-info.c
+++ b/src/plugins/plugin-api-info.c
@@ -802,7 +802,8 @@ plugin_api_info_color_rgb2term_cb (const void *pointer, void *data,
                                    const char *info_name,
                                    const char *arguments)
 {
-    char value[32], *pos, *color;
+    const char *pos;
+    char value[32], *color;
     int rgb, limit;
 
     /* make C compiler happy */