mq_timedsend(), mq_timedsend_monotonic()

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Прототип:

#include <mqueue.h>
#include <time.h>
int mq_timedsend( mqd_t mqdes,
const char *msg_ptr,
size_t msg_len,
unsigned int msg_prio,
const struct timespec *abs_timeout );
int mq_timedsend_monotonic( mqd_t mqdes,
const char *msg_ptr,
size_t msg_len,
unsigned int msg_prio,
const struct timespec *abs_timeout );

Аргументы:

mqdes
The descriptor of the message queue you want to put the message into, returned by mq_open().
msg_ptr
A pointer to the message data.
msg_len
The size of the buffer, in bytes.
msg_prio
The priority of the message, in the range from 0 to (MQ_PRIO_MAX - 1).
abs_timeout
A pointer to a struct timespec that specifies the absolute time (not the relative time to the current time) to wait before the function stops trying to receive messages.

Библиотека:

Описание:

The mq_timedsend() function puts a message of size msg_len and pointed to by msg_ptr into the queue indicated by mqdes. The new message has a priority of msg_prio. The mq_timedsend_monotonic() function is a ЗОСРВ «Нейтрино» extension; it's similar to mq_timedsend(), but it uses CLOCK_MONOTONIC, so the timeout isn't affected by changes to the system time.


Note: Neutrino supports two implementations of message queues: a traditional implementation, and an alternate one that uses asynchronous messages. For more information, see the entries for mq and mqueue.

The queue maintained is in priority order, and in FIFO order within the same priority.

If the number of elements on the specified queue is equal to its mq_maxmsg, and and O_NONBLOCK wasn't set (in the oflag argument to mq_open()), the call to mq_timedsend() blocks. It becomes unblocked when there's room on the queue to send the given message. If more than one mq_timedsend() is blocked on a given queue, and space becomes available in that queue to send, then the mq_timedsend() with the highest priority message is unblocked.

In the traditional (mqueue) implementation, calling write() with mqdes is analogous to calling mq_timedsend() with a msg_prio of 0.

Возвращаемое значение:

-1
Возникла ошибка. Код ошибки записан в errno.
≠-1
Успешное завершение.

Коды ошибок:

EAGAIN
The O_NONBLOCK flag was set when opening the queue, and the specified queue is full.
EBADF
The mqdes argument doesn't represent a valid message queue descriptor, or mqdes isn't opened for writing.
EINTR
The call was interrupted by a signal.
EINVAL
One of the following is true:
EMSGSIZE
The msg_len argument is greater than the msgsize associated with the specified queue.
ETIMEDOUT
The timeout value was exceeded.

Примеры:

See the example for mq_timedreceive().

Классификация:

mq_timedsend() — POSIX 1003.1 MSG; mq_timedsend_monotonic() — ЗОСРВ «Нейтрино»

Точка остановки потока
Да
Обработчик прерываний
Нет
Обработчик сигналов
Да
В потоке
Да

Тематические ссылки:

mq_close(), mq_open(), mq_receive(), mq_send(), mq_timedreceive(), struct timespec

mq, mqueue в Справочнике по Утилитам




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