получить атрибуты очереди сообщений (REALTIME) (get message queue attributes (REALTIME))
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)
mq_getattr — get message queue attributes (REALTIME)
Синопсис (Synopsis)
#include <mqueue.h>
int mq_getattr(mqd_t mqdes, struct mq_attr *mqstat);
Описание (Description)
The mq_getattr() function shall obtain status information and
attributes of the message queue and the open message queue
description associated with the message queue descriptor.
The mqdes argument specifies a message queue descriptor.
The results shall be returned in the mq_attr structure referenced
by the mqstat argument.
Upon return, the following members shall have the values
associated with the open message queue description as set when
the message queue was opened and as modified by subsequent
mq_setattr() calls: mq_flags.
The following attributes of the message queue shall be returned
as set at message queue creation: mq_maxmsg, mq_msgsize.
Upon return, the following members within the mq_attr structure
referenced by the mqstat argument shall be set to the current
state of the message queue:
mq_curmsgs
The number of messages currently on the queue.
Возвращаемое значение (Return value)
Upon successful completion, the mq_getattr() function shall
return zero. Otherwise, the function shall return -1 and set
errno to indicate the error.
Ошибки (Error)
The mq_getattr() function may fail if:
EBADF The mqdes argument is not a valid message queue
descriptor.
The following sections are informative.
Примеры (Examples)
See mq_notify(3p).
Использование в приложениях (Application usage)
None.
Обоснование (Rationale)
None.
Будущие направления (Future directions)
None.
Смотри также (See also)
mq_notify(3p), mq_open(3p), mq_send(3p), mq_setattr(3p),
msgctl(3p), msgget(3p), msgrcv(3p), msgsnd(3p)
The Base Definitions volume of POSIX.1‐2017, mqueue.h(0p)
