atomic_load, atomic_load_explicit
<stdatomic.h>
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.
Contents
[edit] Parameters
[edit] Return value
The current value of the atomic variable pointed to by obj
.
[edit] References
- C17 standard (ISO/IEC 9899:2018):
- 7.17.7.2 The atomic_load generic functions (p: 206)
- C11 standard (ISO/IEC 9899:2011):
- 7.17.7.2 The atomic_load generic functions (p: 282)