Memory-managed wrapper type.

Construct a Once struct initialized to zero.

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 onceInitLeave and the unique address valueLocation, 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:

C code

 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.

Since: 2.14

No description available in the introspection data.

This functions behaves in the same way as onceInitEnter, but can can be used to initialize pointers (or guintptr) instead of gsize.

C code

 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

Since: 2.80

Counterpart to onceInitEnter. 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 onceInitEnter 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.

Since: 2.14

Counterpart to onceInitEnterPointer. 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 onceInitEnterPointer on this initialization variable.

This functions behaves in the same way as onceInitLeave, but can be used to initialize pointers (or guintptr) instead of gsize.

Since: 2.80

Set the value of the “retval” field to Nothing. When overloading is enabled, this is equivalent to

clear #retval

Get the value of the “retval” field. When overloading is enabled, this is equivalent to

get once #retval

Set the value of the “retval” field. When overloading is enabled, this is equivalent to

set once [ #retval := value ]

Get the value of the “status” field. When overloading is enabled, this is equivalent to

get once #status

Set the value of the “status” field. When overloading is enabled, this is equivalent to

set once [ #status := value ]