On 09/11/2015 10:35 AM, Edward Bartolo wrote:
> Hi all,
>
> Since yesterday I have been trying to understand why "char**
> essid_list" is working inside getInstalledEssidList(&count,
> essid_list) but failing as soon as I try to access essid_list[0]
> outside the function.
>
> Both the source and the gdb text output are attached.
>
> Any helpful pointers are appreciated.

Having dynamically growing (and shrinking) lists in C is
always a problem. That's why the problem has been solved
many times. :-)

For example, the singly-linked list, GSList, from the GLIB
library is pretty popular and could save you some time.

I have attached an example program to demonstrate how GSList
can be used to manage a list of allocated C-type strings.

Best regards,
T.

/* An example program for GSList.

 *
 * Compile with:
 *
 *    gcc $(pkg-config --libs glib-2.0 --cflags glib-2.0 ) -o example example.c
 *
 * */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <glib.h>

char * teststring[] = { "hello", "world", NULL };

int main(int argc, char** argv) {
    GSList * list = NULL;

    // Fill the example list:
    char ** a_string = teststring;

    while(*a_string) {
        list = g_slist_append(list, strdup(*a_string));
        a_string++;
    }

    // Iterate the filled list:
    int i = 0, l = g_slist_length(list);

    for(i=0; i<l; i++)
        printf("item #%d is \"%s\"\n", i, g_slist_nth_data(list, i));

    // Free the list and the data strings inside (using free()):
    g_slist_free_full(list, free);

    return 0;
}