mqueue.h

mqueue.h

Overview

Related Modules:

Description:

Provides message queue operation functions and related structures.

For example, you can use the functions to create, open, close, delete, read, and write a message queue, and to obtain and set its attributes.

Since:

1.0

Version:

1.0

Summary

Data Structures

Data Structure Name	Description
mq_attr	Describes message queue attributes.

Functions

Function Name	Description
mq_close (mqd_t mqdes)	int Closes a message queue that is no longer used.
mq_getattr (mqd_t mqdes, struct mq_attr attr)	int Obtains the attributes of the message queue specified by the descriptor. The values of mq_maxmsg, mq_msgsize, and mq_curmsgs are fixed.
mq_open (const char name, int oflag,…)	mqd_t Creates a message queue or opens an existing message queue.
mq_receive (mqd_t mqdes, char buffer, size_t size, unsigned prioptr)	ssize_t Receives a message from a specified message queue.
mq_send (mqd_t mqdes, const char buffer, size_t size, unsigned prio)	int Sends a message to a specified message queue.
mq_setattr (mqd_t mqdes, const struct mq_attr restrict newattr, struct mq_attr *restrict oldattr)	int Sets the attributes of the message queue specified by the descriptor. The mq_maxmsg, mq_msgsize, and mq_curmsgs attributes cannot be modified. mq_flags supports the O_NONBLOCK attribute only.
mq_timedreceive (mqd_t mqdes, char __restrict buffer, size_t size, unsigned restrict prioptr, const struct timespec *restrict timeout)	ssize_t Receives a message from the message queue, with a timeout period specified.
mq_timedsend (mqd_t mqdes, const char buffer, size_t size, unsigned prio, const struct timespec timeout)	int Sends a message to a specified message queue, with a timeout period specified.
mq_unlink (const char *name)	int Decreases the reference count of the message queue by 1, or deletes the message queue if the reference count is 0.