std::atomic::fetch_sub

(since C++11)
(member only of atomic<Integral> template specialization)
T fetch_sub( T arg, 
             std::memory_order order = std::memory_order_seq_cst );
T fetch_sub( T arg, 
             std::memory_order order = std::memory_order_seq_cst ) volatile;
(since C++11)
(member only of atomic<T*> template specialization)
T* fetch_sub( std::ptrdiff_t arg, 
              std::memory_order order = std::memory_order_seq_cst );
T* fetch_sub( std::ptrdiff_t arg, 
              std::memory_order order = std::memory_order_seq_cst ) volatile;

Atomically replaces the current value with the result of arithmetic subtraction of the value and arg. The operation is read-modify-write operation. Memory is affected according to the value of order.

For signed Integral types, arithmetic is defined to use two’s complement representation. There are no undefined results. For T* types, the result may be an undefined address, but the operations otherwise have no undefined behavior.

Parameters

arg - the other argument of arithmetic subtraction
order - memory order constraints to enforce

Return value

The value immediately preceding the effects of this function in the modification order of *this.

Exceptions

noexcept specification:
noexcept

See also

subtracts a non-atomic value from an atomic object and obtains the previous value of the atomic
(function template)
doc_CPP
2016-10-11 10:00:25
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