Add few missing error messages to libvlc.

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

include/vlc/libvlc_media_list.h

@@ -156,7 +156,7 @@ LIBVLC_API libvlc_media_t *
  *
  * \param p_ml a media list instance
  * \param p_md media instance
- * \return position of media instance
+ * \return position of media instance or -1 if media not found
  */
 LIBVLC_API int
     libvlc_media_list_index_of_item( libvlc_media_list_t *p_ml,

src/control/core.c

@@ -114,7 +114,20 @@ void libvlc_release( libvlc_instance_t *p_instance )
 
 int libvlc_add_intf( libvlc_instance_t *p_i, const char *name )
 {
-    return libvlc_InternalAddIntf( p_i->p_libvlc_int, name ) ? -1 : 0;
+    if( libvlc_InternalAddIntf( p_i->p_libvlc_int, name ))
+    {
+        if( name )
+        {
+            libvlc_printerr("interface \"%s\" initialization failed",
+                name );
+        }
+        else
+        {
+            libvlc_printerr("default interface initialization failed");
+        }
+        return -1;
+    }
+    return 0;
 }
 
 void libvlc_set_exit_handler( libvlc_instance_t *p_i, void (*cb) (void *),

src/control/media_library.c

@@ -64,7 +64,10 @@ libvlc_media_library_new( libvlc_instance_t * p_inst )
     p_mlib = malloc(sizeof(libvlc_media_library_t));
 
     if( !p_mlib )
+    {
+        libvlc_printerr( "Not enough memory" );
         return NULL;
+    }
 
     p_mlib->p_libvlc_instance = p_inst;
     p_mlib->i_refcount = 1;

src/control/media_list.c

@@ -454,6 +454,7 @@ int libvlc_media_list_index_of_item( libvlc_media_list_t * p_mlist,
         if( p_searched_md == p_md )
             return i;
     }
+    libvlc_printerr( "Media not found" );
     return -1;
 }