Keep the code consistent.

toxcore/Messenger.c

@@ -1648,44 +1648,48 @@ int Messenger_load(Messenger *m, uint8_t *data, uint32_t length)
 /* Return the number of friends in the instance m.
  * You should use this to determine how much memory to allocate
  * for copy_friendlist. */
-size_t count_friendlist(Messenger *m)
+uint32_t count_friendlist(Messenger *m)
 {
-    size_t ret = 0;
+    uint32_t ret = 0;
     uint32_t i;
+
     for (i = 0; i < m->numfriends; i++) {
         if (m->friendlist[i].status > 0) {
             ret++;
         }
     }
+
     return ret;
 }
 
 /* Copy a list of valid friend IDs into the array out_list.
- * If out_list is NULL, returns -1.
+ * If out_list is NULL, returns 0.
  * Otherwise, returns the number of elements copied.
  * If the array was too small, the contents
  * of out_list will be truncated to list_size. */
-size_t copy_friendlist(Messenger *m, int *out_list, size_t list_size)
+uint32_t copy_friendlist(Messenger *m, int *out_list, uint32_t list_size)
 {
     if (!out_list)
-        return -1;
+        return 0;
-        
+
     if (m->numfriends == 0) {
         return 0;
     }
-    
+
     uint32_t i;
-    size_t ret = 0;
+    uint32_t ret = 0;
+
     for (i = 0; i < m->numfriends; i++) {
         if (i >= list_size) {
             break; /* Abandon ship */
         }
+
         if (m->friendlist[i].status > 0) {
             out_list[i] = i;
             ret++;
         }
     }
-    
+
     return ret;
 }
 

toxcore/Messenger.h

@@ -459,14 +459,14 @@ int Messenger_load(Messenger *m, uint8_t *data, uint32_t length);
 /* Return the number of friends in the instance m.
  * You should use this to determine how much memory to allocate
  * for copy_friendlist. */
-size_t count_friendlist(Messenger *m);
+uint32_t count_friendlist(Messenger *m);
 
 /* Copy a list of valid friend IDs into the array out_list.
- * If out_list is NULL, returns -1.
+ * If out_list is NULL, returns 0.
  * Otherwise, returns the number of elements copied.
  * If the array was too small, the contents
  * of out_list will be truncated to list_size. */
-size_t copy_friendlist(Messenger *m, int *out_list, size_t list_size);
+uint32_t copy_friendlist(Messenger *m, int *out_list, uint32_t list_size);
 
 /* Allocate and return a list of valid friend id's. List must be freed by the
  * caller.

toxcore/tox.c

@@ -265,18 +265,18 @@ void tox_set_sends_receipts(void *tox, int friendnumber, int yesno)
 /* Return the number of friends in the instance m.
  * You should use this to determine how much memory to allocate
  * for copy_friendlist. */
-size_t tox_count_friendlist(void *tox)
+uint32_t tox_count_friendlist(void *tox)
 {
     Messenger *m = tox;
     return count_friendlist(m);
 }
 
 /* Copy a list of valid friend IDs into the array out_list.
- * If out_list is NULL, returns -1.
+ * If out_list is NULL, returns 0.
  * Otherwise, returns the number of elements copied.
  * If the array was too small, the contents
  * of out_list will be truncated to list_size. */
-size_t tox_copy_friendlist(void *tox, int *out_list, size_t list_size)
+uint32_t tox_copy_friendlist(void *tox, int *out_list, uint32_t list_size)
 {
     Messenger *m = tox;
     return copy_friendlist(m, out_list, list_size);

toxcore/tox.h

@@ -283,14 +283,14 @@ void tox_set_sends_receipts(Tox *tox, int friendnumber, int yesno);
 /* Return the number of friends in the instance m.
  * You should use this to determine how much memory to allocate
  * for copy_friendlist. */
-size_t tox_count_friendlist(void *tox);
+uint32_t tox_count_friendlist(void *tox);
-    
+
 /* Copy a list of valid friend IDs into the array out_list.
- * If out_list is NULL, returns -1.
+ * If out_list is NULL, returns 0.
  * Otherwise, returns the number of elements copied.
  * If the array was too small, the contents
  * of out_list will be truncated to list_size. */
-size_t tox_copy_friendlist(void *tox, int *out_list, size_t list_size);
+uint32_t tox_copy_friendlist(void *tox, int *out_list, uint32_t list_size);
 
 /* Set the function that will be executed when a friend request is received.
  *  Function format is function(uint8_t * public_key, uint8_t * data, uint16_t length)