| member only of |
T fetch_sub( T arg, std::memory_order order = std::memory_order_seq_cst ) noexcept;
T fetch_sub( T arg, std::memory_order order = std::memory_order_seq_cst ) volatile noexcept;
| member only of |
T* fetch_sub( std::ptrdiff_t arg, std::memory_order order = std::memory_order_seq_cst ) noexcept;
T* fetch_sub( std::ptrdiff_t arg, std::memory_order order = std::memory_order_seq_cst ) volatile noexcept;
Atomically replaces the current value with the result of arithmetic subtraction of the value and
arg. That is, it performs atomic post-decrement. The operation is read-modify-write operation. Memory is affected according to the value of
Integral types, arithmetic is defined to use two’s complement representation. There are no undefined results.
T* types, the result may be an undefined address, but the operation otherwise has no undefined behavior. The program is ill-formed if
T is not an object type.
For floating-point types, the floating-point environment in effect may be different from the calling thread's floating-point environment. The operation need not be conform to the corresponding
The volatile-qualified versions are deprecated if
|arg||-||the other argument of arithmetic subtraction|
|order||-||memory order constraints to enforce|
The value immediately preceding the effects of this function in the modification order of
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
|DR||Applied to||Behavior as published||Correct behavior|
|P0558R1||C++11||arithmetic permitted on pointers to cv void or function||made ill-formed|
| subtracts a non-atomic value from an atomic object and obtains the previous value of the atomic
| increments or decrements the atomic value by one
(public member function)
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