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std::atomic::fetch_sub(3) C++ Standard Libary std::atomic::fetch_sub(3) NAME std::atomic::fetch_sub - std::atomic::fetch_sub Synopsis member only of atomic<Integral>(C++11) and atomic<Floating>(C++20) template specializations 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 noex- cept; member only of atomic<T*> template specialization (1) T* fetch_sub( std::ptrdiff_t arg, std::memory_order order = std::memory_order_seq_cst ) noexcept; (2) T* fetch_sub( std::ptrdiff_t arg, std::memory_order order = std::memory_order_seq_cst ) volatile noex- cept; 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 order. For signed Integral types, arithmetic is defined to use twos comple- ment representation. There are no undefined results. For T* types, the result may be an undefined address, but the opera- tion 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 std::numeric_lim- its traits but is encouraged to do so. If the result is not a representable value for its type, the result is unspecified but the (since C++20) operation otherwise has no undefined behavior. The volatile-qualified versions are deprecated if std::atomic<T>::is_always_lock_free is false. 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. Defect reports The following behavior-changing defect reports were applied retroac- tively to previously published C++ standards. DR Applied to Behavior as published Correct behavior P0558R1 C++11 arithmetic permitted on pointers to cv void or made ill-formed function See also atomic_fetch_sub subtracts a non-atomic value from an atomic object and atomic_fetch_sub_explicit obtains the previous value of the atomic (C++11) (function template) (C++11) operator++ operator++(int) increments or decrements the atomic value by one operator-- (public member function) operator--(int) http://cppreference.com 2022.07.31 std::atomic::fetch_sub(3)
NAME | Synopsis | Parameters | Return value | See also
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