Use NULL rather than 0 as pointer

modules/visualization/goom.c

@@ -366,7 +366,7 @@ static void Close( vlc_object_t *p_this )
     vlc_join( p_sys->p_thread->thread, NULL );
 
     /* Free data */
-    aout_filter_RequestVout( p_filter, p_sys->p_thread->p_vout, 0 );
+    aout_filter_RequestVout( p_filter, p_sys->p_thread->p_vout, NULL );
     vlc_mutex_destroy( &p_sys->p_thread->lock );
     vlc_cond_destroy( &p_sys->p_thread->wait );
 

modules/visualization/visual/visual.c

@@ -292,7 +292,7 @@ static int Open( vlc_object_t *p_this )
     p_sys->fifo = block_FifoNew();
     if( unlikely( p_sys->fifo == NULL ) )
     {
-        aout_filter_RequestVout( p_filter, p_sys->p_vout, 0 );
+        aout_filter_RequestVout( p_filter, p_sys->p_vout, NULL );
         goto error;
     }
 
@@ -300,7 +300,7 @@ static int Open( vlc_object_t *p_this )
                    VLC_THREAD_PRIORITY_VIDEO ) )
     {
         block_FifoRelease( p_sys->fifo );
-        aout_filter_RequestVout( p_filter, p_sys->p_vout, 0 );
+        aout_filter_RequestVout( p_filter, p_sys->p_vout, NULL );
         goto error;
     }
 
@@ -386,7 +386,7 @@ static void Close( vlc_object_t *p_this )
     vlc_cancel( p_sys->thread );
     vlc_join( p_sys->thread, NULL );
     block_FifoRelease( p_sys->fifo );
-    aout_filter_RequestVout( p_filter, p_filter->p_sys->p_vout, 0 );
+    aout_filter_RequestVout( p_filter, p_filter->p_sys->p_vout, NULL );
 
     /* Free the list */
     for( int i = 0; i < p_sys->i_effect; i++ )