include/vlc_threads.h

@@ -590,8 +590,8 @@ typedef struct
  * Executes a function one time.
  *
  * The first time this function is called with a given one-time initialization
- * object, it executes the provided callback.
- * Any further call with the same object will be a no-op.
+ * object, it executes the provided callback with the provided data pointer as
+ * sole parameter. Any further call with the same object will be a no-op.
  *
  * In the corner case that the first time execution is ongoing in another
  * thread, then the function will wait for completion on the other thread
@@ -601,16 +601,19 @@ typedef struct
  *
  * \param once a one-time initialization object
  * \param cb callback to execute (the first time)
+ * \param opaque data pointer for the callback
  */
-VLC_API void vlc_once(vlc_once_t *restrict once, void (*cb)(void));
+VLC_API void vlc_once(vlc_once_t *restrict once, void (*cb)(void *),
+                      void *opaque);
 
-static inline void vlc_once_inline(vlc_once_t *restrict once, void (*cb)(void))
+static inline void vlc_once_inline(vlc_once_t *restrict once,
+                                   void (*cb)(void *), void *opaque)
 {
     /* Fast path: check if already initialized */
     if (unlikely(atomic_load_explicit(&once->value, memory_order_acquire) < 3))
-        vlc_once(once, cb);
+        vlc_once(once, cb, opaque);
 }
-#define vlc_once(once, cb) vlc_once_inline(once, cb)
+#define vlc_once(once, cb, opaque) vlc_once_inline(once, cb, opaque)
 #endif
 
 /**

modules/codec/gstreamer/gstdecode.c

@@ -328,12 +328,13 @@ static gboolean vlc_gst_plugin_init( GstPlugin *p_plugin )
     return TRUE;
 }
 
-static bool vlc_gst_registered = false;
 
-static void vlc_gst_init_once(void)
+static void vlc_gst_init_once(void *data)
 {
+    bool *registered = data;
+
     gst_init( NULL, NULL );
-    vlc_gst_registered = gst_plugin_register_static( 1, 0, "videolan",
+    *registered = gst_plugin_register_static( 1, 0, "videolan",
                 "VLC Gstreamer plugins", vlc_gst_plugin_init,
                 "1.0.0", "LGPL", "NA", "vlc", "NA" );
 }
@@ -342,8 +343,9 @@ static void vlc_gst_init_once(void)
 static bool vlc_gst_init( void )
 {
     static vlc_once_t once = VLC_STATIC_ONCE;
+    static bool vlc_gst_registered;
 
-    vlc_once(&once, vlc_gst_init_once);
+    vlc_once(&once, vlc_gst_init_once, &vlc_gst_registered);
     return vlc_gst_registered;
 }
 

modules/services_discovery/mtp.c

@@ -79,6 +79,12 @@ typedef struct
     vlc_thread_t thread;
 } services_discovery_sys_t;
 
+static void vlc_libmtp_init(void *data)
+{
+    (void) data;
+    LIBMTP_Init();
+}
+
 /*****************************************************************************
  * Open: initialize and create stuff
  *****************************************************************************/
@@ -95,7 +101,7 @@ static int Open( vlc_object_t *p_this )
 
     static vlc_once_t mtp_init_once = VLC_STATIC_ONCE;
 
-    vlc_once( &mtp_init_once, LIBMTP_Init );
+    vlc_once(&mtp_init_once, LIBMTP_Init, NULL);
 
     if (vlc_clone (&p_sys->thread, Run, p_sd, VLC_THREAD_PRIORITY_LOW))
     {

src/misc/threads.c

@@ -463,7 +463,7 @@ enum { VLC_ONCE_UNDONE, VLC_ONCE_DOING, VLC_ONCE_CONTEND, VLC_ONCE_DONE };
 
 static_assert (VLC_ONCE_DONE == 3, "Check vlc_once in header file");
 
-void (vlc_once)(vlc_once_t *restrict once, void (*cb)(void))
+void (vlc_once)(vlc_once_t *restrict once, void (*cb)(void *), void *opaque)
 {
     unsigned int value = VLC_ONCE_UNDONE;
 
@@ -472,7 +472,7 @@ void (vlc_once)(vlc_once_t *restrict once, void (*cb)(void))
                                                 memory_order_acquire,
                                                 memory_order_acquire)) {
         /* First time: run the callback */
-        cb();
+        cb(opaque);
 
         if (atomic_exchange_explicit(&once->value, VLC_ONCE_DONE,
                                      memory_order_release) == VLC_ONCE_CONTEND)