since: 2.14


g_once_init_enter (
  void* location


Function to be called when starting a critical initialization section. The argument location must point to a static 0-initialized variable that will be set to a value other than 0 at the end of the initialization section. In combination with g_once_init_leave() and the unique address value_location, it can be ensured that an initialization section will be executed only once during a program’s life time, and that concurrent threads are blocked until initialization completed. To be used in constructs like this:

  static gsize initialization_value = 0;

  if (g_once_init_enter (&initialization_value))
      gsize setup_value = 42; // initialization code here

      g_once_init_leave (&initialization_value, setup_value);

  // use initialization_value here

While location has a volatile qualifier, this is a historical artifact and the pointer passed to it should not be volatile.

Available since: 2.14



Type: void*

Location of a static initializable variable containing 0

The argument will be modified by the function.

Return value

Type: gboolean

TRUE if the initialization section should be entered, FALSE and blocks otherwise.