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# atomic_exchange, atomic_exchange_explicit

From cppreference.com
< c‎ | atomic

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 by `obj` with `desired` and returns the value `obj` held previously. The operation is read-modify-write operation. The first version orders memory accesses according to memory_order_seq_cst, the second version orders memory accesses according to `order`.

This is a generic function defined for all atomic object types. `A` is the type of an atomic object, `C` is the non-atomic type corresponding to `A`.

### [edit] Parameters

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

### [edit] Return value

The value held previously be the atomic object pointed to by `obj`.

### [edit] See also

atomic_compare_exchange_strong atomic_compare_exchange_strong_explicit atomic_compare_exchange_weak atomic_compare_exchange_weak_explicit (C11) | swaps a value with the an atomic object if the old value is what is expected, otherwise reads the old value (function) [edit]
C++ documentation for atomic_exchange, atomic_exchange_explicit

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