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Defined in header <stdatomic.h> | ||
C atomic_exchange(volatile A* obj, C desired); | (1) | (since C11) |
C atomic_exchange_explicit(volatile A* obj, C desired,memory_order order); | (2) | (since C11) |
Atomically replaces the value pointed byobj withdesired and returns the valueobj held previously. The operation is read-modify-write operation. The first version orders memory accesses according tomemory_order_seq_cst, the second version orders memory accesses according toorder.
This is ageneric function defined for allatomic object typesA. The argument is pointer to a volatile atomic type to accept addresses of both non-volatile andvolatile (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 toA.
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_exchange)(...)), or a program defines an external identifier with the name of a generic function, the behavior is undefined..
Contents |
| obj | - | pointer to the atomic object to modify |
| desired | - | the value to replace the atomic object with |
| order | - | the memory synchronization ordering for this operation: all values are permitted |
The value held previously be the atomic object pointed to byobj.
| swaps a value with an atomic object if the old value is what is expected, otherwise reads the old value (function)[edit] | |
C++ documentation foratomic_exchange,atomic_exchange_explicit | |
