уничтожить и инициализировать объект барьера (destroy and initialize a barrier object)
Пролог (Prolog)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
Имя (Name)
pthread_barrier_destroy, pthread_barrier_init — destroy and
initialize a barrier object
Синопсис (Synopsis)
#include <pthread.h>
int pthread_barrier_destroy(pthread_barrier_t *barrier);
int pthread_barrier_init(pthread_barrier_t *restrict barrier,
const pthread_barrierattr_t *restrict attr, unsigned count);
Описание (Description)
The pthread_barrier_destroy() function shall destroy the barrier
referenced by barrier and release any resources used by the
barrier. The effect of subsequent use of the barrier is undefined
until the barrier is reinitialized by another call to
pthread_barrier_init(). An implementation may use this function
to set barrier to an invalid value. The results are undefined if
pthread_barrier_destroy() is called when any thread is blocked on
the barrier, or if this function is called with an uninitialized
barrier.
The pthread_barrier_init() function shall allocate any resources
required to use the barrier referenced by barrier and shall
initialize the barrier with attributes referenced by attr. If
attr is NULL, the default barrier attributes shall be used; the
effect is the same as passing the address of a default barrier
attributes object. The results are undefined if
pthread_barrier_init() is called when any thread is blocked on
the barrier (that is, has not returned from the
pthread_barrier_wait() call). The results are undefined if a
barrier is used without first being initialized. The results are
undefined if pthread_barrier_init() is called specifying an
already initialized barrier.
The count argument specifies the number of threads that must call
pthread_barrier_wait() before any of them successfully return
from the call. The value specified by count must be greater than
zero.
If the pthread_barrier_init() function fails, the barrier shall
not be initialized and the contents of barrier are undefined.
See Section 2.9.9, Synchronization Object Copies and Alternative
Mappings for further requirements.
Возвращаемое значение (Return value)
Upon successful completion, these functions shall return zero;
otherwise, an error number shall be returned to indicate the
error.
Ошибки (Error)
The pthread_barrier_init() function shall fail if:
EAGAIN The system lacks the necessary resources to initialize
another barrier.
EINVAL The value specified by count is equal to zero.
ENOMEM Insufficient memory exists to initialize the barrier.
These functions shall not return an error code of [EINTR].
The following sections are informative.
Примеры (Examples)
None.
Использование в приложениях (Application usage)
None.
Обоснование (Rationale)
If an implementation detects that the value specified by the
barrier argument to pthread_barrier_destroy() does not refer to
an initialized barrier object, it is recommended that the
function should fail and report an [EINVAL] error.
If an implementation detects that the value specified by the attr
argument to pthread_barrier_init() does not refer to an
initialized barrier attributes object, it is recommended that the
function should fail and report an [EINVAL] error.
If an implementation detects that the value specified by the
barrier argument to pthread_barrier_destroy() or
pthread_barrier_init() refers to a barrier that is in use (for
example, in a pthread_barrier_wait() call) by another thread, or
detects that the value specified by the barrier argument to
pthread_barrier_init() refers to an already initialized barrier
object, it is recommended that the function should fail and
report an [EBUSY] error.
Будущие направления (Future directions)
None.
Смотри также (See also)
pthread_barrier_wait(3p)
The Base Definitions volume of POSIX.1‐2017, pthread.h(0p)
