Staticinit_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
Staticinit_Staticinit_This functions behaves in the same way as g_once_init_enter(), but can
can be used to initialize pointers (or guintptr) instead of gsize.
static MyStruct *interesting_struct = NULL;
if (g_once_init_enter_pointer (&interesting_struct))
{
MyStruct *setup_value = allocate_my_struct (); // initialization code here
g_once_init_leave_pointer (&interesting_struct, g_steal_pointer (&setup_value));
}
// use interesting_struct here
location of a static initializable variable containing NULL
Staticinit_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
Staticinit_Counterpart to g_once_init_enter_pointer(). Expects a location of a static
NULL-initialized initialization variable, and an initialization value
other than NULL. Sets the variable to the initialization value, and
releases concurrent threads blocking in g_once_init_enter_pointer() on this
initialization variable.
This functions behaves in the same way as g_once_init_leave(), but
can be used to initialize pointers (or guintptr) instead of gsize.
location of a static initializable variable containing NULL
Optionalresult: anynew non-NULL value for *location
A GLib.Once struct controls a one-time initialization function. Any one-time initialization function must have its own unique GLib.Once struct.
Since
2.4