std::atomic_flag::test_and_set
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                    < cpp | atomic | atomic flag
                    
                                                            
                    |   Defined in header <atomic>
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|   bool test_and_set(std::memory_order order = std::memory_order_seq_cst) volatile;  | 
(1) | (since C++11) | 
|   bool test_and_set(std::memory_order order = std::memory_order_seq_cst);  | 
(2) | (since C++11) | 
Atomically changes the state of a std::atomic_flag to set (true) and returns the value it held before.
[edit] Parameters
| order | - | the memory sycnhronization ordering for this operation | 
[edit] Exceptions
[edit] See also
|    atomically sets flag to false   (public member function)  | |
|    atomically sets the flag to true and returns its previous value   (function)  | |
|    (C++11)  | 
   defines memory ordering constraints for the given atomic operation   (typedef)  |