Difference between revisions of "c/thread"
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These features are optionally provided: | These features are optionally provided: | ||
* if the macro constant {{tt|__STDC_NO_THREADS__}} is defined by the compiler, the header {{tt|<threads.h>}} and all of the names provided in it are not provided; | * if the macro constant {{tt|__STDC_NO_THREADS__}} is defined by the compiler, the header {{tt|<threads.h>}} and all of the names provided in it are not provided; | ||
− | * if the macro constant {{tt|__STDC_NO_ATOMICS__}} is defined by the compiler, the header {{ | + | * if the macro constant {{tt|__STDC_NO_ATOMICS__}} is defined by the compiler, the header {{header|stdatomic.h}} and all of the names provided in it are not provided. |
+ | |||
+ | See also [[c/language/atomic|{{ttb|_Atomic}} type specifier and qualifier]]. | ||
===Threads=== | ===Threads=== | ||
{{dsc begin}} | {{dsc begin}} | ||
− | {{dsc header | threads.h}} | + | {{dsc header|threads.h}} |
− | {{dsc inc | c/thread/dsc thrd_t}} | + | {{dsc inc|c/thread/dsc thrd_t}} |
− | {{dsc inc | c/thread/dsc thrd_create}} | + | {{dsc inc|c/thread/dsc thrd_create}} |
− | {{dsc inc | c/thread/dsc thrd_equal}} | + | {{dsc inc|c/thread/dsc thrd_equal}} |
− | {{dsc inc | c/thread/dsc thrd_current}} | + | {{dsc inc|c/thread/dsc thrd_current}} |
− | {{dsc inc | c/thread/dsc thrd_sleep}} | + | {{dsc inc|c/thread/dsc thrd_sleep}} |
− | {{dsc inc | c/thread/dsc thrd_yield}} | + | {{dsc inc|c/thread/dsc thrd_yield}} |
− | {{dsc inc | c/thread/dsc thrd_exit}} | + | {{dsc inc|c/thread/dsc thrd_exit}} |
− | {{dsc inc | c/thread/dsc thrd_detach}} | + | {{dsc inc|c/thread/dsc thrd_detach}} |
− | {{dsc inc | c/thread/dsc thrd_join}} | + | {{dsc inc|c/thread/dsc thrd_join}} |
− | {{dsc inc | c/thread/dsc thrd_errors}} | + | {{dsc inc|c/thread/dsc thrd_errors}} |
− | {{dsc inc | c/thread/dsc thrd_start_t}} | + | {{dsc inc|c/thread/dsc thrd_start_t}} |
{{dsc end}} | {{dsc end}} | ||
===Atomic operations=== | ===Atomic operations=== | ||
{{dsc begin}} | {{dsc begin}} | ||
− | {{dsc header | stdatomic.h}} | + | {{dsc header|stdatomic.h}} |
− | {{dsc h2 | Operations on atomic types}} | + | {{dsc h2|Operations on atomic types}} |
− | {{dsc inc | c/atomic/dsc ATOMIC_LOCK_FREE_consts}} | + | {{dsc inc|c/atomic/dsc ATOMIC_LOCK_FREE_consts}} |
− | {{dsc inc | c/atomic/dsc atomic_is_lock_free}} | + | {{dsc inc|c/atomic/dsc atomic_is_lock_free}} |
− | {{dsc inc | c/atomic/dsc atomic_store}} | + | {{dsc inc|c/atomic/dsc atomic_store}} |
− | {{dsc inc | c/atomic/dsc atomic_load}} | + | {{dsc inc|c/atomic/dsc atomic_load}} |
− | {{dsc inc | c/atomic/dsc atomic_exchange}} | + | {{dsc inc|c/atomic/dsc atomic_exchange}} |
− | {{dsc inc | c/atomic/dsc atomic_compare_exchange}} | + | {{dsc inc|c/atomic/dsc atomic_compare_exchange}} |
− | {{dsc inc | c/atomic/dsc atomic_fetch_add}} | + | {{dsc inc|c/atomic/dsc atomic_fetch_add}} |
− | {{dsc inc | c/atomic/dsc atomic_fetch_sub}} | + | {{dsc inc|c/atomic/dsc atomic_fetch_sub}} |
− | {{dsc inc | c/atomic/dsc atomic_fetch_or}} | + | {{dsc inc|c/atomic/dsc atomic_fetch_or}} |
− | {{dsc inc | c/atomic/dsc atomic_fetch_xor}} | + | {{dsc inc|c/atomic/dsc atomic_fetch_xor}} |
− | {{dsc inc | c/atomic/dsc atomic_fetch_and}} | + | {{dsc inc|c/atomic/dsc atomic_fetch_and}} |
− | {{dsc h2 | Flag type and operations}} | + | {{dsc h2|Flag type and operations}} |
− | {{dsc inc | c/atomic/dsc atomic_flag}} | + | {{dsc inc|c/atomic/dsc atomic_flag}} |
− | {{dsc inc | c/atomic/dsc atomic_flag_test_and_set}} | + | {{dsc inc|c/atomic/dsc atomic_flag_test_and_set}} |
− | {{dsc inc | c/atomic/dsc atomic_flag_clear}} | + | {{dsc inc|c/atomic/dsc atomic_flag_clear}} |
− | {{dsc h2 | Initialization}} | + | {{dsc h2|Initialization}} |
− | {{dsc inc | c/atomic/dsc atomic_init}} | + | {{dsc inc|c/atomic/dsc atomic_init}} |
− | {{dsc inc | c/atomic/dsc ATOMIC_VAR_INIT}} | + | {{dsc inc|c/atomic/dsc ATOMIC_VAR_INIT}} |
− | {{dsc inc | c/atomic/dsc ATOMIC_FLAG_INIT}} | + | {{dsc inc|c/atomic/dsc ATOMIC_FLAG_INIT}} |
− | {{dsc h2 | Memory synchronization ordering}} | + | {{dsc h2|Memory synchronization ordering}} |
− | {{dsc inc | c/atomic/dsc memory_order}} | + | {{dsc inc|c/atomic/dsc memory_order}} |
− | {{dsc inc | c/atomic/dsc kill_dependency}} | + | {{dsc inc|c/atomic/dsc kill_dependency}} |
− | {{dsc inc | c/atomic/dsc atomic_thread_fence}} | + | {{dsc inc|c/atomic/dsc atomic_thread_fence}} |
− | {{dsc inc | c/atomic/dsc atomic_signal_fence}} | + | {{dsc inc|c/atomic/dsc atomic_signal_fence}} |
− | {{dsc h2 | Convenience type aliases}} | + | {{dsc h2|Convenience type aliases}} |
− | {{dsc hitem | Typedef name | Full type name }} | + | {{dsc hitem|Typedef name|Full type name}} |
− | {{dsc | {{tt|atomic_bool}}{{mark c11}} | {{c|_Atomic _Bool}} }} | + | {{dsc|{{tt|atomic_bool}}{{mark c11}}|{{c|_Atomic _Bool}}}} |
− | {{dsc | {{tt|atomic_char}}{{mark c11}} | {{c|_Atomic char}} }} | + | {{dsc|{{tt|atomic_char}}{{mark c11}}|{{c|_Atomic char}}}} |
− | {{dsc | {{tt|atomic_schar}}{{mark c11}} | {{c|_Atomic signed char}} }} | + | {{dsc|{{tt|atomic_schar}}{{mark c11}}|{{c|_Atomic signed char}}}} |
− | {{dsc | {{tt|atomic_uchar}}{{mark c11}} | {{c|_Atomic unsigned char}} }} | + | {{dsc|{{tt|atomic_uchar}}{{mark c11}}|{{c|_Atomic unsigned char}}}} |
− | {{dsc | {{tt|atomic_short}}{{mark c11}} | {{c|_Atomic short}} }} | + | {{dsc|{{tt|atomic_short}}{{mark c11}}|{{c|_Atomic short}}}} |
− | {{dsc | {{tt|atomic_ushort}}{{mark c11}} | {{c|_Atomic unsigned short}} }} | + | {{dsc|{{tt|atomic_ushort}}{{mark c11}}|{{c|_Atomic unsigned short}}}} |
− | {{dsc | {{tt|atomic_int}}{{mark c11}} | {{c|_Atomic int}} }} | + | {{dsc|{{tt|atomic_int}}{{mark c11}}|{{c|_Atomic int}}}} |
− | {{dsc | {{tt|atomic_uint}}{{mark c11}} | {{c|_Atomic unsigned int}} }} | + | {{dsc|{{tt|atomic_uint}}{{mark c11}}|{{c|_Atomic unsigned int}}}} |
− | {{dsc | {{tt|atomic_long}}{{mark c11}} | {{c|_Atomic long}} }} | + | {{dsc|{{tt|atomic_long}}{{mark c11}}|{{c|_Atomic long}}}} |
− | {{dsc | {{tt|atomic_ulong}}{{mark c11}} | {{c|_Atomic unsigned long}} }} | + | {{dsc|{{tt|atomic_ulong}}{{mark c11}}|{{c|_Atomic unsigned long}}}} |
− | {{dsc | {{tt|atomic_llong}}{{mark c11}} | {{c|_Atomic long long}} }} | + | {{dsc|{{tt|atomic_llong}}{{mark c11}}|{{c|_Atomic long long}}}} |
− | {{dsc | {{tt|atomic_ullong}}{{mark c11}} | {{c|_Atomic unsigned long long}} }} | + | {{dsc|{{tt|atomic_ullong}}{{mark c11}}|{{c|_Atomic unsigned long long}}}} |
− | {{dsc | {{tt|atomic_char8_t}}{{mark c23}} | {{c|_Atomic char8_t}} }} | + | {{dsc|{{tt|atomic_char8_t}}{{mark c23}}|{{c|_Atomic char8_t}}}} |
− | {{dsc | {{tt|atomic_char16_t}}{{mark c11}} | {{c|_Atomic char16_t}} }} | + | {{dsc|{{tt|atomic_char16_t}}{{mark c11}}|{{c|_Atomic char16_t}}}} |
− | {{dsc | {{tt|atomic_char32_t}}{{mark c11}} | {{c|_Atomic char32_t}} }} | + | {{dsc|{{tt|atomic_char32_t}}{{mark c11}}|{{c|_Atomic char32_t}}}} |
− | {{dsc | {{tt|atomic_wchar_t}}{{mark c11}} | {{c|_Atomic wchar_t}} }} | + | {{dsc|{{tt|atomic_wchar_t}}{{mark c11}}|{{c|_Atomic wchar_t}}}} |
− | {{dsc | {{tt|atomic_int_least8_t}}{{mark c11}} | {{c|_Atomic int_least8_t}} }} | + | {{dsc|{{tt|atomic_int_least8_t}}{{mark c11}}|{{c|_Atomic int_least8_t}}}} |
− | {{dsc | {{tt|atomic_uint_least8_t}}{{mark c11}} | {{c|_Atomic uint_least8_t}} }} | + | {{dsc|{{tt|atomic_uint_least8_t}}{{mark c11}}|{{c|_Atomic uint_least8_t}}}} |
− | {{dsc | {{tt|atomic_int_least16_t}}{{mark c11}} | {{c|_Atomic int_least16_t}} }} | + | {{dsc|{{tt|atomic_int_least16_t}}{{mark c11}}|{{c|_Atomic int_least16_t}}}} |
− | {{dsc | {{tt|atomic_uint_least16_t}}{{mark c11}} | {{c|_Atomic uint_least16_t}} }} | + | {{dsc|{{tt|atomic_uint_least16_t}}{{mark c11}}|{{c|_Atomic uint_least16_t}}}} |
− | {{dsc | {{tt|atomic_int_least32_t}}{{mark c11}} | {{c|_Atomic int_least32_t}} }} | + | {{dsc|{{tt|atomic_int_least32_t}}{{mark c11}}|{{c|_Atomic int_least32_t}}}} |
− | {{dsc | {{tt|atomic_uint_least32_t}}{{mark c11}} | {{c|_Atomic uint_least32_t}} }} | + | {{dsc|{{tt|atomic_uint_least32_t}}{{mark c11}}|{{c|_Atomic uint_least32_t}}}} |
− | {{dsc | {{tt|atomic_int_least64_t}}{{mark c11}} | {{c|_Atomic int_least64_t}} }} | + | {{dsc|{{tt|atomic_int_least64_t}}{{mark c11}}|{{c|_Atomic int_least64_t}}}} |
− | {{dsc | {{tt|atomic_uint_least64_t}}{{mark c11}} | {{c|_Atomic uint_least64_t}} }} | + | {{dsc|{{tt|atomic_uint_least64_t}}{{mark c11}}|{{c|_Atomic uint_least64_t}}}} |
− | {{dsc | {{tt|atomic_int_fast8_t}}{{mark c11}} | {{c|_Atomic int_fast8_t}} }} | + | {{dsc|{{tt|atomic_int_fast8_t}}{{mark c11}}|{{c|_Atomic int_fast8_t}}}} |
− | {{dsc | {{tt|atomic_uint_fast8_t}}{{mark c11}} | {{c|_Atomic uint_fast8_t}} }} | + | {{dsc|{{tt|atomic_uint_fast8_t}}{{mark c11}}|{{c|_Atomic uint_fast8_t}}}} |
− | {{dsc | {{tt|atomic_int_fast16_t}}{{mark c11}} | {{c|_Atomic int_fast16_t}} }} | + | {{dsc|{{tt|atomic_int_fast16_t}}{{mark c11}}|{{c|_Atomic int_fast16_t}}}} |
− | {{dsc | {{tt|atomic_uint_fast16_t}}{{mark c11}} | {{c|_Atomic uint_fast16_t}} }} | + | {{dsc|{{tt|atomic_uint_fast16_t}}{{mark c11}}|{{c|_Atomic uint_fast16_t}}}} |
− | {{dsc | {{tt|atomic_int_fast32_t}}{{mark c11}} | {{c|_Atomic int_fast32_t}} }} | + | {{dsc|{{tt|atomic_int_fast32_t}}{{mark c11}}|{{c|_Atomic int_fast32_t}}}} |
− | {{dsc | {{tt|atomic_uint_fast32_t}}{{mark c11}} | {{c|_Atomic uint_fast32_t}} }} | + | {{dsc|{{tt|atomic_uint_fast32_t}}{{mark c11}}|{{c|_Atomic uint_fast32_t}}}} |
− | {{dsc | {{tt|atomic_int_fast64_t}}{{mark c11}} | {{c|_Atomic int_fast64_t}} }} | + | {{dsc|{{tt|atomic_int_fast64_t}}{{mark c11}}|{{c|_Atomic int_fast64_t}}}} |
− | {{dsc | {{tt|atomic_uint_fast64_t}}{{mark c11}} | {{c|_Atomic uint_fast64_t}} }} | + | {{dsc|{{tt|atomic_uint_fast64_t}}{{mark c11}}|{{c|_Atomic uint_fast64_t}}}} |
− | {{dsc | {{tt|atomic_intptr_t}}{{mark c11}} | {{c|_Atomic intptr_t}} }} | + | {{dsc|{{tt|atomic_intptr_t}}{{mark c11}}|{{c|_Atomic intptr_t}}}} |
− | {{dsc | {{tt|atomic_uintptr_t}}{{mark c11}} | {{c|_Atomic uintptr_t}} }} | + | {{dsc|{{tt|atomic_uintptr_t}}{{mark c11}}|{{c|_Atomic uintptr_t}}}} |
− | {{dsc | {{tt|atomic_size_t}}{{mark c11}} | {{c|_Atomic size_t}} }} | + | {{dsc|{{tt|atomic_size_t}}{{mark c11}}|{{c|_Atomic size_t}}}} |
− | {{dsc | {{tt|atomic_ptrdiff_t}}{{mark c11}} | {{c|_Atomic ptrdiff_t}} }} | + | {{dsc|{{tt|atomic_ptrdiff_t}}{{mark c11}}|{{c|_Atomic ptrdiff_t}}}} |
− | {{dsc | {{tt|atomic_intmax_t}}{{mark c11}} | {{c|_Atomic intmax_t}} }} | + | {{dsc|{{tt|atomic_intmax_t}}{{mark c11}}|{{c|_Atomic intmax_t}}}} |
− | {{dsc | {{tt|atomic_uintmax_t}}{{mark c11}} | {{c|_Atomic uintmax_t}} }} | + | {{dsc|{{tt|atomic_uintmax_t}}{{mark c11}}|{{c|_Atomic uintmax_t}}}} |
{{dsc end}} | {{dsc end}} | ||
===Mutual exclusion=== | ===Mutual exclusion=== | ||
{{dsc begin}} | {{dsc begin}} | ||
− | {{dsc header | threads.h}} | + | {{dsc header|threads.h}} |
− | {{dsc inc | c/thread/dsc mtx_t}} | + | {{dsc inc|c/thread/dsc mtx_t}} |
− | {{dsc inc | c/thread/dsc mtx_init}} | + | {{dsc inc|c/thread/dsc mtx_init}} |
− | {{dsc inc | c/thread/dsc mtx_lock}} | + | {{dsc inc|c/thread/dsc mtx_lock}} |
− | {{dsc inc | c/thread/dsc mtx_timedlock}} | + | {{dsc inc|c/thread/dsc mtx_timedlock}} |
− | {{dsc inc | c/thread/dsc mtx_trylock}} | + | {{dsc inc|c/thread/dsc mtx_trylock}} |
− | {{dsc inc | c/thread/dsc mtx_unlock}} | + | {{dsc inc|c/thread/dsc mtx_unlock}} |
− | {{dsc inc | c/thread/dsc mtx_destroy}} | + | {{dsc inc|c/thread/dsc mtx_destroy}} |
− | {{dsc inc | c/thread/dsc mtx_types}} | + | {{dsc inc|c/thread/dsc mtx_types}} |
− | {{dsc h2 | Call once}} | + | {{dsc h2|Call once}} |
− | {{dsc inc | c/thread/dsc call_once}} | + | {{dsc inc|c/thread/dsc call_once}} |
{{dsc end}} | {{dsc end}} | ||
===Condition variables=== | ===Condition variables=== | ||
{{dsc begin}} | {{dsc begin}} | ||
− | {{dsc header | threads.h}} | + | {{dsc header|threads.h}} |
− | {{dsc | {{ttb|cnd_t}} | condition variable identifier | notes={{mark c11}}}} | + | {{dsc|{{ttb|cnd_t}}|condition variable identifier|notes={{mark c11}}}} |
− | {{dsc inc | c/thread/dsc cnd_init}} | + | {{dsc inc|c/thread/dsc cnd_init}} |
− | {{dsc inc | c/thread/dsc cnd_signal}} | + | {{dsc inc|c/thread/dsc cnd_signal}} |
− | {{dsc inc | c/thread/dsc cnd_broadcast}} | + | {{dsc inc|c/thread/dsc cnd_broadcast}} |
− | {{dsc inc | c/thread/dsc cnd_wait}} | + | {{dsc inc|c/thread/dsc cnd_wait}} |
− | {{dsc inc | c/thread/dsc cnd_timedwait}} | + | {{dsc inc|c/thread/dsc cnd_timedwait}} |
− | {{dsc inc | c/thread/dsc cnd_destroy}} | + | {{dsc inc|c/thread/dsc cnd_destroy}} |
{{dsc end}} | {{dsc end}} | ||
===Thread-local storage=== | ===Thread-local storage=== | ||
{{dsc begin}} | {{dsc begin}} | ||
− | {{dsc header | threads.h}} | + | {{dsc header|threads.h}} |
− | {{dsc inc | c/thread/dsc thread_local}} | + | {{dsc inc|c/thread/dsc thread_local}} |
− | {{dsc inc | c/thread/dsc tss_t}} | + | {{dsc inc|c/thread/dsc tss_t}} |
− | {{dsc inc | c/thread/dsc TSS_DTOR_ITERATIONS}} | + | {{dsc inc|c/thread/dsc TSS_DTOR_ITERATIONS}} |
− | {{dsc inc | c/thread/dsc tss_dtor_t}} | + | {{dsc inc|c/thread/dsc tss_dtor_t}} |
− | {{dsc inc | c/thread/dsc tss_create}} | + | {{dsc inc|c/thread/dsc tss_create}} |
− | {{dsc inc | c/thread/dsc tss_get}} | + | {{dsc inc|c/thread/dsc tss_get}} |
− | {{dsc inc | c/thread/dsc tss_set}} | + | {{dsc inc|c/thread/dsc tss_set}} |
− | {{dsc inc | c/thread/dsc tss_delete}} | + | {{dsc inc|c/thread/dsc tss_delete}} |
{{dsc end}} | {{dsc end}} | ||
Line 137: | Line 139: | ||
In future revisions of the C standard: | In future revisions of the C standard: | ||
* function names, type names, and enumeration constants that begin with either {{tt|cnd_}}, {{tt|mtx_}}, {{tt|thrd_}}, or {{tt|tss_}}, and a lowercase letter may be added to the declarations in the {{tt|<threads.h>}} header; | * function names, type names, and enumeration constants that begin with either {{tt|cnd_}}, {{tt|mtx_}}, {{tt|thrd_}}, or {{tt|tss_}}, and a lowercase letter may be added to the declarations in the {{tt|<threads.h>}} header; | ||
− | * macros that begin with {{tt|ATOMIC_}} and an uppercase letter may be added to the macros defined in the {{ | + | * macros that begin with {{tt|ATOMIC_}} and an uppercase letter may be added to the macros defined in the {{header|stdatomic.h}} header; |
− | * typedef names that begin with either {{tt|atomic_}} or {{tt|memory_}}, and a lowercase letter may be added to the declarations in the {{ | + | * typedef names that begin with either {{tt|atomic_}} or {{tt|memory_}}, and a lowercase letter may be added to the declarations in the {{header|stdatomic.h}} header; |
− | * enumeration constants that begin with {{tt|memory_order_}} and a lowercase letter may be added to the definition of the {{lc|memory_order}} type in the {{ | + | * enumeration constants that begin with {{tt|memory_order_}} and a lowercase letter may be added to the definition of the {{lc|memory_order}} type in the {{header|stdatomic.h}} header; |
− | * function names that begin with {{tt|atomic_}} and a lowercase letter may be added to the declarations in the {{ | + | * function names that begin with {{tt|atomic_}} and a lowercase letter may be added to the declarations in the {{header|stdatomic.h}} header. |
− | Identifiers reserved for functions names are always {{rev inl|since=c23|potentially}} reserved for use as identifiers with external linkage, while other identifiers list here are {{rev inl|since=c23|potentially}} reserved when {{ | + | Identifiers reserved for functions names are always {{rev inl|since=c23|potentially}} reserved for use as identifiers with external linkage, while other identifiers list here are {{rev inl|since=c23|potentially}} reserved when {{header|stdatomic.h}} is included. |
Declaring, defining, or {{c|#undef}}ing such an identifier results in undefined behavior{{rev inl|since=c23| if it is provided by the standard or implementation}}. Portable programs should not use those identifiers. | Declaring, defining, or {{c|#undef}}ing such an identifier results in undefined behavior{{rev inl|since=c23| if it is provided by the standard or implementation}}. Portable programs should not use those identifiers. | ||
===References=== | ===References=== | ||
+ | {{ref std c23}} | ||
+ | {{ref std|section=7.17|title=Atomics <stdatomic.h>|p=TBD}} | ||
+ | {{ref std|section=7.26|title=Threads <threads.h>|p=TBD}} | ||
+ | {{ref std|section=7.31.8|title=Atomics <stdatomic.h>|p=TBD}} | ||
+ | {{ref std|section=7.31.15|title=Threads <threads.h>|p=TBD}} | ||
+ | {{ref std end}} | ||
{{ref std c17}} | {{ref std c17}} | ||
− | {{ref std | section=7.17 | title=Atomics <stdatomic.h> | p=200-209}} | + | {{ref std|section=7.17|title=Atomics <stdatomic.h>|p=200-209}} |
− | {{ref std | section=7.26 | title=Threads <threads.h> | p=274-283}} | + | {{ref std|section=7.26|title=Threads <threads.h>|p=274-283}} |
− | {{ref std | section=7.31.8 | title=Atomics <stdatomic.h> | p=332}} | + | {{ref std|section=7.31.8|title=Atomics <stdatomic.h>|p=332}} |
− | {{ref std | section=7.31.15 | title=Threads <threads.h> | p=333}} | + | {{ref std|section=7.31.15|title=Threads <threads.h>|p=333}} |
{{ref std end}} | {{ref std end}} | ||
{{ref std c11}} | {{ref std c11}} | ||
− | {{ref std | section=7.17 | title=Atomics <stdatomic.h> | p=273-286}} | + | {{ref std|section=7.17|title=Atomics <stdatomic.h>|p=273-286}} |
− | {{ref std | section=7.26 | title=Threads <threads.h> | p=376-387}} | + | {{ref std|section=7.26|title=Threads <threads.h>|p=376-387}} |
− | {{ref std | section=7.31.8 | title=Atomics <stdatomic.h> | p=455-456}} | + | {{ref std|section=7.31.8|title=Atomics <stdatomic.h>|p=455-456}} |
− | {{ref std | section=7.31.15 | title=Threads <threads.h> | p=456}} | + | {{ref std|section=7.31.15|title=Threads <threads.h>|p=456}} |
{{ref std end}} | {{ref std end}} | ||
===See also=== | ===See also=== | ||
{{dsc begin}} | {{dsc begin}} | ||
− | {{dsc see cpp | cpp/thread | Concurrency support library | nomono=true | + | {{dsc see cpp|cpp/thread|Concurrency support library|nomono=true}} |
− | + | ||
{{dsc end}} | {{dsc end}} | ||
+ | |||
+ | ===External links=== | ||
+ | {{eli|[https://www.gnu.org/software/libc/manual/html_node/ISO-C-Mutexes.html GNU GCC Libc Manual: ISO C Mutexes]}} | ||
{{langlinks|ar|cs|de|es|fr|it|ja|ko|pl|pt|ru|tr|zh}} | {{langlinks|ar|cs|de|es|fr|it|ja|ko|pl|pt|ru|tr|zh}} |
Latest revision as of 02:14, 14 August 2023
C includes built-in support for threads, atomic operations, mutual exclusion, condition variables, and thread-specific storages.
These features are optionally provided:
- if the macro constant
__STDC_NO_THREADS__
is defined by the compiler, the header<threads.h>
and all of the names provided in it are not provided; - if the macro constant
__STDC_NO_ATOMICS__
is defined by the compiler, the header <stdatomic.h> and all of the names provided in it are not provided.
See also _Atomic
type specifier and qualifier.
Contents |
[edit] Threads
Defined in header
<threads.h> | |
thrd_t
|
implementation-defined complete object type identifying a thread |
(C11) |
creates a thread (function) |
(C11) |
checks if two identifiers refer to the same thread (function) |
(C11) |
obtains the current thread identifier (function) |
(C11) |
suspends execution of the calling thread for the given period of time (function) |
(C11) |
yields the current time slice (function) |
(C11) |
terminates the calling thread (function) |
(C11) |
detaches a thread (function) |
(C11) |
blocks until a thread terminates (function) |
indicates a thread error status (constant) | |
thrd_start_t (C11) |
a typedef of the function pointer type int(*)(void*), used by thrd_create (typedef) |
[edit] Atomic operations
Defined in header
<stdatomic.h> | |
Operations on atomic types | |
indicates that the given atomic type is lock-free (macro constant) | |
(C11) |
indicates whether the atomic object is lock-free (function) |
stores a value in an atomic object (function) | |
reads a value from an atomic object (function) | |
swaps a value with the value of an atomic object (function) | |
swaps a value with an atomic object if the old value is what is expected, otherwise reads the old value (function) | |
atomic addition (function) | |
atomic subtraction (function) | |
atomic bitwise OR (function) | |
atomic bitwise exclusive OR (function) | |
atomic bitwise AND (function) | |
Flag type and operations | |
(C11) |
lock-free atomic boolean flag (struct) |
sets an atomic_flag to true and returns the old value (function) | |
sets an atomic_flag to false (function) | |
Initialization | |
(C11) |
initializes an existing atomic object (function) |
(C11)(deprecated in C17)(removed in C23) |
initializes a new atomic object (function macro) |
(C11) |
initializes a new atomic_flag (macro constant) |
Memory synchronization ordering | |
(C11) |
defines memory ordering constraints (enum) |
(C11) |
breaks a dependency chain for memory_order_consume (function macro) |
(C11) |
generic memory order-dependent fence synchronization primitive (function) |
(C11) |
fence between a thread and a signal handler executed in the same thread (function) |
Convenience type aliases | |
Typedef name | Full type name |
atomic_bool (C11)
|
_Atomic _Bool |
atomic_char (C11)
|
_Atomic char |
atomic_schar (C11)
|
_Atomic signed char |
atomic_uchar (C11)
|
_Atomic unsigned char |
atomic_short (C11)
|
_Atomic short |
atomic_ushort (C11)
|
_Atomic unsigned short |
atomic_int (C11)
|
_Atomic int |
atomic_uint (C11)
|
_Atomic unsigned int |
atomic_long (C11)
|
_Atomic long |
atomic_ulong (C11)
|
_Atomic unsigned long |
atomic_llong (C11)
|
_Atomic long long |
atomic_ullong (C11)
|
_Atomic unsigned long long |
atomic_char8_t (C23)
|
_Atomic char8_t |
atomic_char16_t (C11)
|
_Atomic char16_t |
atomic_char32_t (C11)
|
_Atomic char32_t |
atomic_wchar_t (C11)
|
_Atomic wchar_t |
atomic_int_least8_t (C11)
|
_Atomic int_least8_t |
atomic_uint_least8_t (C11)
|
_Atomic uint_least8_t |
atomic_int_least16_t (C11)
|
_Atomic int_least16_t |
atomic_uint_least16_t (C11)
|
_Atomic uint_least16_t |
atomic_int_least32_t (C11)
|
_Atomic int_least32_t |
atomic_uint_least32_t (C11)
|
_Atomic uint_least32_t |
atomic_int_least64_t (C11)
|
_Atomic int_least64_t |
atomic_uint_least64_t (C11)
|
_Atomic uint_least64_t |
atomic_int_fast8_t (C11)
|
_Atomic int_fast8_t |
atomic_uint_fast8_t (C11)
|
_Atomic uint_fast8_t |
atomic_int_fast16_t (C11)
|
_Atomic int_fast16_t |
atomic_uint_fast16_t (C11)
|
_Atomic uint_fast16_t |
atomic_int_fast32_t (C11)
|
_Atomic int_fast32_t |
atomic_uint_fast32_t (C11)
|
_Atomic uint_fast32_t |
atomic_int_fast64_t (C11)
|
_Atomic int_fast64_t |
atomic_uint_fast64_t (C11)
|
_Atomic uint_fast64_t |
atomic_intptr_t (C11)
|
_Atomic intptr_t |
atomic_uintptr_t (C11)
|
_Atomic uintptr_t |
atomic_size_t (C11)
|
_Atomic size_t |
atomic_ptrdiff_t (C11)
|
_Atomic ptrdiff_t |
atomic_intmax_t (C11)
|
_Atomic intmax_t |
atomic_uintmax_t (C11)
|
_Atomic uintmax_t |
[edit] Mutual exclusion
Defined in header
<threads.h> | |
mtx_t
|
mutex identifier |
(C11) |
creates a mutex (function) |
(C11) |
blocks until locks a mutex (function) |
(C11) |
blocks until locks a mutex or times out (function) |
(C11) |
locks a mutex or returns without blocking if already locked (function) |
(C11) |
unlocks a mutex (function) |
(C11) |
destroys a mutex (function) |
(C11)(C11)(C11) |
defines the type of a mutex (enum) |
Call once | |
(C11) |
calls a function exactly once (function) |
[edit] Condition variables
Defined in header
<threads.h> | |
cnd_t
|
condition variable identifier |
(C11) |
creates a condition variable (function) |
(C11) |
unblocks one thread blocked on a condition variable (function) |
(C11) |
unblocks all threads blocked on a condition variable (function) |
(C11) |
blocks on a condition variable (function) |
(C11) |
blocks on a condition variable, with a timeout (function) |
(C11) |
destroys a condition variable (function) |
[edit] Thread-local storage
Defined in header
<threads.h> | |
(C11)(removed in C23) |
convenience macro for storage-class specifier _Thread_local (keyword macro) |
tss_t
|
thread-specific storage pointer |
(C11) |
maximum number of times destructors are called (macro constant) |
tss_dtor_t (C11) |
function pointer type void(*)(void*), used for TSS destructor (typedef) |
(C11) |
creates thread-specific storage pointer with a given destructor (function) |
(C11) |
reads from thread-specific storage (function) |
(C11) |
write to thread-specific storage (function) |
(C11) |
releases the resources held by a given thread-specific pointer (function) |
[edit] Reserved identifiers
In future revisions of the C standard:
- function names, type names, and enumeration constants that begin with either
cnd_
,mtx_
,thrd_
, ortss_
, and a lowercase letter may be added to the declarations in the<threads.h>
header; - macros that begin with
ATOMIC_
and an uppercase letter may be added to the macros defined in the <stdatomic.h> header; - typedef names that begin with either
atomic_
ormemory_
, and a lowercase letter may be added to the declarations in the <stdatomic.h> header; - enumeration constants that begin with
memory_order_
and a lowercase letter may be added to the definition of the memory_order type in the <stdatomic.h> header; - function names that begin with
atomic_
and a lowercase letter may be added to the declarations in the <stdatomic.h> header.
Identifiers reserved for functions names are always potentially(since C23) reserved for use as identifiers with external linkage, while other identifiers list here are potentially(since C23) reserved when <stdatomic.h> is included.
Declaring, defining, or #undefing such an identifier results in undefined behavior if it is provided by the standard or implementation(since C23). Portable programs should not use those identifiers.
[edit] References
- C23 standard (ISO/IEC 9899:2024):
- 7.17 Atomics <stdatomic.h> (p: TBD)
- 7.26 Threads <threads.h> (p: TBD)
- 7.31.8 Atomics <stdatomic.h> (p: TBD)
- 7.31.15 Threads <threads.h> (p: TBD)
- C17 standard (ISO/IEC 9899:2018):
- 7.17 Atomics <stdatomic.h> (p: 200-209)
- 7.26 Threads <threads.h> (p: 274-283)
- 7.31.8 Atomics <stdatomic.h> (p: 332)
- 7.31.15 Threads <threads.h> (p: 333)
- C11 standard (ISO/IEC 9899:2011):
- 7.17 Atomics <stdatomic.h> (p: 273-286)
- 7.26 Threads <threads.h> (p: 376-387)
- 7.31.8 Atomics <stdatomic.h> (p: 455-456)
- 7.31.15 Threads <threads.h> (p: 456)
[edit] See also
C++ documentation for Concurrency support library
|
[edit] External links
GNU GCC Libc Manual: ISO C Mutexes |