GLibonce

The first call to this routine by a process with a given GOnce struct calls func with the given argument. Thereafter, subsequent calls to g_once() with the same GOnce struct do not call func again, but return the stored result of the first call. On return from g_once(), the status of once will be G_ONCE_STATUS_READY.

For example, a mutex or a thread-specific data key must be created exactly once. In a threaded environment, calling g_once() ensures that the initialization is serialized across multiple threads.

Calling g_once() recursively on the same GOnce struct in func will lead to a deadlock.

  gpointer
  get_debug_flags (void)
  {
    static GOnce my_once = G_ONCE_INIT;

    g_once (&my_once, parse_debug_flags, NULL);

    return my_once.retval;
  }

Available since: 2.4

This function is not directly available to language bindings.