std::atomic::operator+=,-=,&=,|=,^=

 

C++

Language

Standard library headers

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

 

Atomic operations library

Types

atomic (C++11)

atomic_is_lock_free (C++11)

Functions

atomic_storeatomic_store_explicit (C++11)(C++11)

atomic_loadatomic_load_explicit (C++11)(C++11)

atomic_exchangeatomic_exchange_explicit (C++11)(C++11)

atomic_compare_exchange_weakatomic_compare_exchange_weak_explicitatomic_compare_exchange_strongatomic_compare_exchange_strong_explicit (C++11)(C++11)(C++11)(C++11)

atomic_fetch_addatomic_fetch_add_explicit (C++11)(C++11)

atomic_fetch_subatomic_fetch_sub_explicit (C++11)(C++11)

atomic_fetch_andatomic_fetch_and_explicit (C++11)(C++11)

atomic_fetch_oratomic_fetch_or_explicit (C++11)(C++11)

atomic_fetch_xoratomic_fetch_xor_explicit (C++11)(C++11)

Atomic flags

atomic_flag (C++11)

atomic_flag_test_and_setatomic_flag_test_and_set_explicit (C++11)(C++11)

atomic_flag_clearatomic_flag_clear_explicit (C++11)(C++11)

Initialization

atomic_init (C++11)

ATOMIC_VAR_INIT (C++11)

ATOMIC_FLAG_INIT (C++11)

Memory ordering

memory_order (C++11)

kill_dependency (C++11)

atomic_thread_fence (C++11)

atomic_signal_fence (C++11)

 

std::atomic

Member functions

atomic::atomic

atomic::operator=

atomic::is_lock_free

atomic::store

atomic::load

atomic::operator T

atomic::exchange

atomic::compare_exchange

Specialized member functions

atomic::fetch_add

atomic::fetch_sub

atomic::fetch_and

atomic::fetch_or

atomic::fetch_xor

atomic::operator++atomic::operator++(int)atomic::operator--atomic::operator--(int)

atomic::operator+=atomic::operator-=atomic::operator&=atomic::operator|=atomic::operator^=

 

(1)

(since C++11) (member only of atomic<Integral> template specialization)

T operator+=( T arg );

T operator+=( T arg ) volatile;

(1)

(since C++11) (member only of atomic<T*> template specialization)

T* operator+=( std::ptrdiff_t arg );

T* operator+=( std::ptrdiff_t arg ) volatile;

(2)

(since C++11) (member only of atomic<Integral> template specialization)

T operator-=( T arg );

T operator-=( T arg ) volatile;

(2)

(since C++11) (member only of atomic<T*> template specialization)

T* operator-=( std::ptrdiff_t arg );

T* operator-=( std::ptrdiff_t arg ) volatile;

(3)

(since C++11) (member only of atomic<Integral> template specialization)

T operator&=( T arg );

T operator&=( T arg ) volatile;

(4)

(since C++11) (member only of atomic<Integral> template specialization)

T operator|=( T arg );

T operator|=( T arg ) volatile;

(5)

(since C++11) (member only of atomic<Integral> template specialization)

T operator^=( T arg );

T operator^=( T arg ) volatile;

Atomically replaces the current value with the result of computation involving the previous value and arg. The operation is read-modify-write operation.

1) Performs atomic addition. Equivalent to fetch_add(arg) + arg.

2) Performs atomic subtraction. Equivalent to fetch_sub(arg) - arg.

3) Performs atomic bitwise and. Equivalent to fetch_and(arg) & arg.

4) Performs atomic bitwise or. Equivalent to fetch_or(arg) | arg.

5) Performs atomic bitwise exclusive or. Equivalent to fetch_xor(arg) ^ arg.

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 argument for the arithmetic operation

Return value

The resulting value (that is, the result of applying the corresponding binary operator to the value immediately preceding the effects of the corresponding member function in the modification order of *this)

Exceptions

noexcept specification:  

noexcept

  

Notes

Unlike most compound assignment operators, the compound assignment operators for atomic types do not return a reference to their left-hand arguments. They return a copy of the stored value instead.

See also

operator++operator++(int)operator--operator--(int)

increments or decrements the atomic value by one (public member function)