diff --git a/src/common/completion.c b/src/common/completion.c
index 324fc7f7d..2450dd315 100644
--- a/src/common/completion.c
+++ b/src/common/completion.c
@@ -118,7 +118,7 @@ completion_get_command_infos (t_completion *completion,
                               char **template, int *max_arg)
 {
     t_weechat_alias *ptr_alias;
-    char *ptr_command, *pos;
+    char *ptr_command, *ptr_command2, *pos;
     int i, length;
 #ifdef PLUGINS
     t_weechat_plugin *ptr_plugin;
@@ -138,11 +138,13 @@ completion_get_command_infos (t_completion *completion,
     else
         ptr_command = completion->base_command;
 
-    pos = strchr (ptr_command, ' ');
+    ptr_command2 = strdup (ptr_command);
+    if (!ptr_command2)
+        return;
+    
+    pos = strchr (ptr_command2, ' ');
     if (pos)
-        length = pos - ptr_command;
-    else
-        length = strlen (ptr_command);
+        pos[0] = '\0';
     
 #ifdef PLUGINS
     /* look for plugin command handler */
@@ -153,11 +155,12 @@ completion_get_command_infos (t_completion *completion,
              ptr_handler; ptr_handler = ptr_handler->next_handler)
         {
             if ((ptr_handler->type == HANDLER_COMMAND)
-                && (ascii_strncasecmp (ptr_handler->command,
-                                       ptr_command, length) == 0))
+                && (ascii_strcasecmp (ptr_handler->command,
+                                      ptr_command2) == 0))
             {
                 *template = ptr_handler->completion_template;
                 *max_arg = MAX_ARGS;
+                free (ptr_command2);
                 return;
             }
         }
@@ -167,11 +170,12 @@ completion_get_command_infos (t_completion *completion,
     /* look for WeeChat internal command */
     for (i = 0; weechat_commands[i].command_name; i++)
     {
-        if (ascii_strncasecmp (weechat_commands[i].command_name,
-                               ptr_command, length) == 0)
+        if (ascii_strcasecmp (weechat_commands[i].command_name,
+                              ptr_command2) == 0)
         {
             *template = weechat_commands[i].completion_template;
             *max_arg = weechat_commands[i].max_arg;
+            free (ptr_command2);
             return;
         }
     }
@@ -180,15 +184,17 @@ completion_get_command_infos (t_completion *completion,
     for (i = 0; irc_commands[i].command_name; i++)
     {
         if ((irc_commands[i].cmd_function_args || irc_commands[i].cmd_function_1arg)
-            && (ascii_strncasecmp (irc_commands[i].command_name,
-                                   ptr_command, length) == 0))
+            && (ascii_strcasecmp (irc_commands[i].command_name,
+                                  ptr_command2) == 0))
         {
             *template = irc_commands[i].completion_template;
             *max_arg = irc_commands[i].max_arg;
+            free (ptr_command2);
             return;
         }
     }
     
+    free (ptr_command2);
     return;
 }
 
diff --git a/weechat/src/common/completion.c b/weechat/src/common/completion.c
index 324fc7f7d..2450dd315 100644
--- a/weechat/src/common/completion.c
+++ b/weechat/src/common/completion.c
@@ -118,7 +118,7 @@ completion_get_command_infos (t_completion *completion,
                               char **template, int *max_arg)
 {
     t_weechat_alias *ptr_alias;
-    char *ptr_command, *pos;
+    char *ptr_command, *ptr_command2, *pos;
     int i, length;
 #ifdef PLUGINS
     t_weechat_plugin *ptr_plugin;
@@ -138,11 +138,13 @@ completion_get_command_infos (t_completion *completion,
     else
         ptr_command = completion->base_command;
 
-    pos = strchr (ptr_command, ' ');
+    ptr_command2 = strdup (ptr_command);
+    if (!ptr_command2)
+        return;
+    
+    pos = strchr (ptr_command2, ' ');
     if (pos)
-        length = pos - ptr_command;
-    else
-        length = strlen (ptr_command);
+        pos[0] = '\0';
     
 #ifdef PLUGINS
     /* look for plugin command handler */
@@ -153,11 +155,12 @@ completion_get_command_infos (t_completion *completion,
              ptr_handler; ptr_handler = ptr_handler->next_handler)
         {
             if ((ptr_handler->type == HANDLER_COMMAND)
-                && (ascii_strncasecmp (ptr_handler->command,
-                                       ptr_command, length) == 0))
+                && (ascii_strcasecmp (ptr_handler->command,
+                                      ptr_command2) == 0))
             {
                 *template = ptr_handler->completion_template;
                 *max_arg = MAX_ARGS;
+                free (ptr_command2);
                 return;
             }
         }
@@ -167,11 +170,12 @@ completion_get_command_infos (t_completion *completion,
     /* look for WeeChat internal command */
     for (i = 0; weechat_commands[i].command_name; i++)
     {
-        if (ascii_strncasecmp (weechat_commands[i].command_name,
-                               ptr_command, length) == 0)
+        if (ascii_strcasecmp (weechat_commands[i].command_name,
+                              ptr_command2) == 0)
         {
             *template = weechat_commands[i].completion_template;
             *max_arg = weechat_commands[i].max_arg;
+            free (ptr_command2);
             return;
         }
     }
@@ -180,15 +184,17 @@ completion_get_command_infos (t_completion *completion,
     for (i = 0; irc_commands[i].command_name; i++)
     {
         if ((irc_commands[i].cmd_function_args || irc_commands[i].cmd_function_1arg)
-            && (ascii_strncasecmp (irc_commands[i].command_name,
-                                   ptr_command, length) == 0))
+            && (ascii_strcasecmp (irc_commands[i].command_name,
+                                  ptr_command2) == 0))
         {
             *template = irc_commands[i].completion_template;
             *max_arg = irc_commands[i].max_arg;
+            free (ptr_command2);
             return;
         }
     }
     
+    free (ptr_command2);
     return;
 }