ATOMIC_*_LOCK_FREE
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C
Concurrency support (C11)
Concurrency support library
Threads
Atomic operations
(until C23)
ATOMIC_***_LOCK_FREE
Atomic flags
Memory ordering
Mutual exclusion
Condition variables
Thread-local storage
Defined in header
<stdatomic.h>
#define ATOMIC_BOOL_LOCK_FREE /* implementation-defined */
(since C11)
#define ATOMIC_CHAR_LOCK_FREE /* implementation-defined */
#define ATOMIC_CHAR16_T_LOCK_FREE /* implementation-defined */
#define ATOMIC_CHAR32_T_LOCK_FREE /* implementation-defined */
#define ATOMIC_WCHAR_T_LOCK_FREE /* implementation-defined */
#define ATOMIC_SHORT_LOCK_FREE /* implementation-defined */
#define ATOMIC_INT_LOCK_FREE /* implementation-defined */
#define ATOMIC_LONG_LOCK_FREE /* implementation-defined */
#define ATOMIC_LLONG_LOCK_FREE /* implementation-defined */
#define ATOMIC_CHAR8_T_LOCK_FREE /* implementation-defined */
(since C23)
Expands to preprocessor constant expressions that evaluate to either 0, 1, or 2 which indicate the lock-free property of the corresponding atomic types (both signed and unsigned).
Value
Explanation
0
The atomic type is never lock-free
1
The atomic type is sometimes lock-free
2
The atomic type is always lock-free
[edit] References
- C17 standard (ISO/IEC 9899:2018):
- 7.17.1/3 atomic lock-free macros (p: 200)
- C11 standard (ISO/IEC 9899:2011):
- 7.17.1/3 atomic lock-free macros (p: 273)