mq_setattr2
Set message queue attributes (realtime)
Usage
#include <mqueue.h>
int
mq_setattr(mqd_t mqdes, const struct mq_attr *restrict mqstat, struct mq_attr *restrict omqstat);
Library
library “librt”
Overview
The mq_setattr() system call sets attributes associated with the open message queue description referenced by the message queue descriptor specified by mqdes. The message queue attributes corresponding to the following members defined in the mq_attr structure will be set to the specified values upon successful completion of mq_setattr():
- mq_flags
-
The value of this member is zero or O_NONBLOCK.
The values of the mq_maxmsg, mq_msgsize, and mq_curmsgs members of the mq_attr structure are ignored by mq_setattr().
Return values
Upon successful completion, the function returns a value of zero and the attributes of the message queue will have been changed as specified.
Otherwise, the message queue attributes are unchanged, and the function returns a value of -1 and sets the global variable errno to indicate the error.
Errors
The mq_setattr() system call will fail if:
- [EBADF]
-
The mqdes argument is not a valid message queue descriptor.
Releases
44 releases since FreeBSD 7.0-RELEASE; the text changed 30 times.