the value returned by the call to the function, if status
is %G_ONCE_STATUS_READY
the status of the #GOnce
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.
location of a static initializable variable containing 0
Counterpart to g_once_init_enter(). Expects a location of a static 0-initialized initialization variable, and an initialization value other than 0. Sets the variable to the initialization value, and releases concurrent threads blocking in g_once_init_enter() on this initialization variable.
While location has a volatile qualifier, this is a historical artifact and
the pointer passed to it should not be volatile.
location of a static initializable variable containing 0
new non-0 value for *value_location
A #GOnce struct controls a one-time initialization function. Any one-time initialization function must have its own unique #GOnce struct.