atomic_load, atomic_load_explicit

Defined in header <stdatomic.h>
C atomic_load ( const volatile A * obj ) ;	(1)	(since C11)
C atomic_load_explicit ( const volatile A * obj, memory_order order ) ;	(2)	(since C11)

Atomically loads and returns the current value of the atomic variable pointed to by obj . The operation is atomic read operation.

The first version orders memory accesses according to memory_order_seq_cst , the second version orders memory accesses according to order . order must be one of memory_order_relaxed , memory_order_consume , memory_order_acquire or memory_order_seq_cst . Otherwise the behavior is undefined.

This is a generic function defined for all atomic object types A . The argument is pointer to a volatile atomic type to accept addresses of both non-volatile and volatile (e.g. memory-mapped I/O) atomic objects, and volatile semantic is preserved when applying this operation to volatile atomic objects. C is the non-atomic type corresponding to A .

It is unspecified whether the name of a generic function is a macro or an identifier declared with external linkage. If a macro definition is suppressed in order to access an actual function (e.g. parenthesized like ( atomic_load ) ( ... ) ), or a program defines an external identifier with the name of a generic function, the behavior is undefined.

Parameters

obj	-	pointer to the atomic object to access
order	-	the memory synchronization ordering for this operation

Return value

The current value of the atomic variable pointed to by obj .

References

See also

atomic_store atomic_store_explicit (C11)	stores a value in an atomic object (function)
C++ documentation for atomic_load , atomic_load_explicit