mq_setattr(3) Library Functions Manual mq_setattr(3)
NAME
mq_setattr - Sets the mq_flags attributes associated with a message queue (P1003.1b)
LIBRARY
Realtime Library (librt.so, librt.a)
SYNOPSIS
#include <mqueue.h>
int mq_setattr (
mqd_t mqdes,
const struct mq_attr *mqstat,
struct mq_attr *omqstat);
PARAMETERS
mqdes Describes the message queue for which attributes are to be set.
*mqstat Specifies a pointer to a mq_attr structure that specifies attributes to be set for the specified message queue.
*omqstat Specifies a pointer to a mq_attr structure that stores the previous message queue attributes and the current queue status.
These are the values that would be returned by a call to the mq_getattr function at that point.
DESCRIPTION
The mq_setattr function sets the mq_flags attributes associated with the message queue descriptor for the calling process. Only the block-
ing attribute of the queue for the calling process can be modified through this call. Modifying the blocking attribute for a queue has no
effect on currently blocked processes. Other members of the mq_attr structure are ignored by the mq_setattr function.
RETURN VALUES
On successful completion, the function returns the value 0 (zero) and the message queue attributes will have been changed as specified.
Otherwise, the value -1 is returned, errno is set to indicate the error, and the message queue attributes remain unchanged.
ERRORS
The mq_setattr function fails under the following conditions:
[EBADF] The mqdes argument is not a valid message queue descriptor.
[EINVAL] The mqstat argument is a NULL pointer.
RELATED INFORMATION
Functions: mq_open(3), mq_send(3)
Guide to Realtime Programming delim off
mq_setattr(3)
