atomic_exchange, atomic_exchange_explicit
From cppreference.com
                    
                                        
                    
                    
                                                            
                    |   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. 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 variables.C is the non-atomic type corresponding to A..
Contents | 
[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] References
- C11 standard (ISO/IEC 9899:2011):
 
- 7.17.7.3 The atomic_exchange generic functions (p: 283)
 
[edit] See also
|    swaps a value with the an atomic object if the old value is what is expected, otherwise reads the old value   (function)  | |
|   C++ documentation for atomic_exchange, atomic_exchange_explicit 
 | |