Atomically adds @val to the value of @atomic.
Think of this operation as an atomic version of { tmp = *atomic; *atomic += val; return tmp; }.
This call acts as a full compiler and hardware memory barrier.
a pointer to a #gpointer-sized value
the value to add
Return: the value of @atomic before the add, signed
2.30
See Implementation
Atomically adds @val to the value of @atomic.
Think of this operation as an atomic version of { tmp = *atomic; *atomic += val; return tmp; }.
This call acts as a full compiler and hardware memory barrier.