mq_setattr - Sets the mq_options attributes associated
with a message queue (P1003.1b)
int mq_setattr ( mqd_t mqdes, const struct mq_attr *mqstat,
struct mq_attr *omqstat);
Realtime Library (librt.so, librt.a)
Describes the message queue for which attributes are to be
set. Specifies a pointer to a mq_attr structure that
specifies attributes to be set for the specified message
queue. 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
The mq_setattr function sets the mq_options attributes
associated with the message queue descriptor for the calling
process. Only the blocking 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.
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
The mq_setattr function fails under the following conditions:
The mqdes argument is not a valid message queue
descriptor. The mqstat argument is a NULL pointer.
Functions: mq_open(3), mq_send(3)
Guide to Realtime Programming
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