Atomic operations library

From Cppreference

C++ Standard Library
Language 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)
Atomic operations library
Types atomic (C++11) atomic_is_lock_free (C++11) Functions atomic_store atomic_store_explicit (C++11) (C++11) atomic_load atomic_load_explicit (C++11) (C++11) atomic_exchange atomic_exchange_explicit (C++11) (C++11) atomic_compare_exchange_weak atomic_compare_exchange_weak_explicit atomic_compare_exchange_strong atomic_compare_exchange_strong_explicit (C++11) (C++11) (C++11) (C++11) atomic_fetch_add atomic_fetch_add_explicit (C++11) (C++11) atomic_fetch_sub atomic_fetch_sub_explicit (C++11) (C++11) atomic_fetch_and atomic_fetch_and_explicit (C++11) (C++11) atomic_fetch_or atomic_fetch_or_explicit (C++11) (C++11) atomic_fetch_xor atomic_fetch_xor_explicit (C++11) (C++11) Atomic flags atomic_flag (C++11) atomic_flag_test_and_set atomic_flag_test_and_set_explicit (C++11) (C++11) atomic_flag_clear atomic_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)

The atomic library provides components for fine-grained atomic operations allowing for lockless concurrent programming. Each atomic operation is indivisible with regards to any other atomic operation that involves the same object.

Defined in header <atomic>
Contents 1 Atomic types 2 Operations on atomic types 3 Flag type and operations 4 Initialization 5 Memory synchronization ordering Atomic types
atomic (C++11)	atomic class template and specializations for bool, integral, and pointer types (class template)
atomic_is_lock_free (C++11)	checks if the atomic type's operations are lock-free (function template)
Operations on atomic types
atomic_store atomic_store_explicit (C++11) (C++11)	atomically replaces the value of the atomic object with a non-atomic argument (function template)
atomic_load atomic_load_explicit (C++11) (C++11)	atomically obtains the value stored in an atomic object (function template)
atomic_exchange atomic_exchange_explicit (C++11) (C++11)	atomically replaces the value of the atomic object with non-atomic argument and returns the old value of the atomic (function template)
atomic_compare_exchange_weak atomic_compare_exchange_weak_explicit atomic_compare_exchange_strong atomic_compare_exchange_strong_explicit (C++11) (C++11) (C++11) (C++11)	atomically compares the value of the atomic object with non-atomic argument and performs atomic exchange if equal or atomic load if not (function template)
atomic_fetch_add atomic_fetch_add_explicit (C++11) (C++11)	adds a non-atomic value to an atomic object and obtains the previous value of the atomic (function template)
atomic_fetch_sub atomic_fetch_sub_explicit (C++11) (C++11)	subtracts a non-atomic value from an atomic object and obtains the previous value of the atomic (function template)
atomic_fetch_and atomic_fetch_and_explicit (C++11) (C++11)	replaces the atomic object with the result of logical AND with a non-atomic argument and obtains the previous value of the atomic (function template)
atomic_fetch_or atomic_fetch_or_explicit (C++11) (C++11)	replaces the atomic object with the result of logical OR with a non-atomic argument and obtains the previous value of the atomic (function template)
atomic_fetch_xor atomic_fetch_xor_explicit (C++11) (C++11)	replaces the atomic object with the result of logical XOR with a non-atomic argument and obtains the previous value of the atomic (function template)
Flag type and operations
atomic_flag (C++11)	the lock-free boolean atomic type (class)
atomic_flag_test_and_set atomic_flag_test_and_set_explicit (C++11) (C++11)	atomically sets the flag to true and returns its previous value (function)
atomic_flag_clear atomic_flag_clear_explicit (C++11) (C++11)	atomically sets the value of the flag to false (function)
Initialization
atomic_init (C++11)	non-atomic initialization of a default-constructed atomic object (function template)
ATOMIC_VAR_INIT (C++11)	constant initialization of an atomic variable of static storage duration (function macro)
ATOMIC_FLAG_INIT (C++11)	initializes an std::atomic_flag to false (macro constant)
Memory synchronization ordering
memory_order (C++11)	defines memory ordering constraints for the given atomic operation (typedef)
kill_dependency (C++11)	removes the specified object from the std::memory_order_consume dependency tree (function template)
atomic_thread_fence (C++11)	generic memory order-dependent fence synchronization primitive (function)
atomic_signal_fence (C++11)	fence between a thread and a signal handler executed in the same thread (function)