Introduction
These are types that encapsulate a value whose access is guaranteed to not cause data races and can be used to synchronize memory accesses among different threads and he 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.
Atomic type
| Sr.No. | Member types & Definition |
|---|---|
| 1 |
Atomic class template and specializations for bool, integral, and pointer types |
C-style atomic types
The following are atomic types and also defined in this header.
| contained type | atomic type | description |
|---|---|---|
bool |
atomic_bool | |
char |
atomic_char |
atomics for fundamental integral types. These are either typedefs of the corresponding full specialization of the atomic class template or a base class of such specialization. |
signed char |
atomic_schar | |
unsigned char |
atomic_uchar | |
short |
atomic_short | |
unsigned short |
atomic_ushort | |
int |
atomic_int | |
unsigned int |
atomic_uint | |
long |
atomic_long | |
unsigned long |
atomic_ulong | |
long long |
atomic_llong | |
unsigned long long |
atomic_ullong | |
wchar_t |
atomic_wchar_t | |
char16_t |
atomic_char16_t | |
char32_t |
atomic_char32_t | |
| intmax_t | atomic_intmax_t |
atomics for width-based integrals (those defined in <cinttypes>). Each of these is either an alias of one of the above atomics for fundamental integral types or of a full specialization of the atomic class template with an extended integral type. Where N is one in 8, 16, 32, 64, or any other type width supported by the library. |
| uintmax_t | atomic_uintmax_t | |
int_leastN_t |
atomic_int_leastN_t |
|
uint_leastN_t |
atomic_uint_leastN_t |
|
int_fastN_t |
atomic_int_fastN_t |
|
uint_fastN_t |
atomic_uint_fastN_t |
|
| intptr_t | atomic_intptr_t | |
| uintptr_t | atomic_uintptr_t | |
| size_t | atomic_size_t | |
| ptrdiff_t | atomic_ptrdiff_t |
Operations on atomic types
| Sr.No. | Operations & Definition |
|---|---|
| 1 |
It is used to checks if the atomic type”s operations are lock-free |
| 2 |
It automically replaces the value of the atomic object with a non-atomic argument |
| 3 |
It atomically obtains the value stored in an atomic object |
| 4 |
It atomically replaces the value of the atomic object with non-atomic argument and returns the old value of the atomic |
| 5 |
It atomically compares the value of the atomic object with non-atomic argument and performs atomic exchange if equal or atomic load if not |
| 6 |
It adds a non-atomic value to an atomic object and obtains the previous value of the atomic |
| 7 |
It subtracts a non-atomic value from an atomic object and obtains the previous value of the atomic |
| 8 |
It replaces the atomic object with the result of logical AND with a non-atomic argument and obtains the previous value of the atomic |
| 9 |
It replaces the atomic object with the result of logical OR with a non-atomic argument and obtains the previous value of the atomic |
| 10 |
It replaces the atomic object with the result of logical XOR with a non-atomic argument and obtains the previous value of the atomic |
Flag type and operations
| Sr.No. | Flag type & Definition |
|---|---|
| 1 |
The lock-free boolean atomic type |
| 2 |
It atomically sets the flag to true and returns its previous value |
| 3 |
It atomically sets the value of the flag to false |