mqueue.h

    IPC

    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

    Function Name

    Description

    mq_close (mqd_t mqdes)

    int 

    Closes a message queue that is no longer used.

    (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.

    (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 

    (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 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.

    (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.

    (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.

    (const char *name)

    Decreases the reference count of the message queue by 1, or deletes the message queue if the reference count is 0.