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Joel · Posted: Mon Mar 08, 2010 4:08 pm Post subject: question about g_list_index

My list:

Code: (C)
1 2 3 4 5 6 7 8	GList *list = NULL; list = g_list_append (list, "b1"); // 0 list = g_list_append (list, "b2"); // 1 list = g_list_append (list, "b3"); // 2 //...

The user needs to input either "b1", "b2", ... and later I need to get the position of that input.
Seems that reading the docs about "g_list_index", the last parameter needs to be "const" pointer, so using this:

Code: (C)
1 2 3 4	gint ret = scanf("%s", op); // if op == "b2" gint pos = g_list_index(list,op); // pos should be 1

Doesn't work, returns -1...any alternative ideas?

tadeboro · Posted: Mon Mar 08, 2010 6:58 pm Post subject:

Hi.

g_list_index() function directly compares pointers. If you want to retrieve list item with specific string, you'll probably need to use g_list_find_custom(). After you've obtained the list item with proper string, you can get it's index by calling g_list_position().

If you want to be more efficient, you can write down a loop like this that will replace g_list_find_custom() and g_list_position():

Code: (C)
1 2 3 4 5 6 7 8 9 10 11 12 13	GList list, iter; gint index; gchar search_term = "Some string"; / Initialize your list here / for( index = 0, iter = list; iter; index++, iter = g_list_next( iter ) ) if( ! strcmp( iter->data, search_term ) ) break; / Index now holds your desired item index */

Tadej

Joel · Posted: Tue Mar 09, 2010 1:19 am Post subject:

Thanks, that function helped..another question about the function:

Code: (C)
1 2 3 4 5 6 7 8 9 10 11	gint get_list_index (GList list, const gchar item) { GList *iter = list; // is about "iter" gint index = 0; for( ; iter; index++, iter = g_list_next( iter ) ) if( ! g_strcmp0( iter->data, item ) ) break; return index; }

Does "iter" need to be free with g_list_free?