(since C++11) (member only of `atomic<` 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.

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 `*this`

.

`noexcept`

specification: `noexcept`

(C++11)(C++11) | subtracts a non-atomic value from an atomic object and obtains the previous value of the atomic (function template) |

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