MQ_SETATTR(3C) Standard C Library Functions MQ_SETATTR(3C)

NAME

mq_setattr - set/get message queue attributes

SYNOPSIS

#include <mqueue.h>

int mq_setattr(mqd_t mqdes, const struct mq_attr *mqstat,
struct mq_attr *omqstat);

DESCRIPTION

The mq_setattr() function is used to set 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 are set to the specified values upon
successful completion of mq_setattr():

mq_flags
The value of this member is either 0 or O_NONBLOCK.


The values of mq_maxmsg, mq_msgsize, and mq_curmsgs are ignored by
mq_setattr().


If omqstat is non-NULL, mq_setattr() stores, in the location referenced
by omqstat, the previous message queue attributes and the current queue
status. These values are the same as would be returned by a call to
mq_getattr() at that point.

RETURN VALUES

Upon successful completion, mq_setattr() returns 0 and the attributes of
the message queue will have been changed as specified. Otherwise, the
message queue attributes are unchanged, and the function returns -1 and
sets errno to indicate the error.

ERRORS

The mq_setattr() function will fail if:

EBADF
The mqdes argument is not a valid message queue descriptor.


ENOSYS
The mq_setattr() function is not supported by the system.

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-------------------+
|Interface Stability | Committed |
+--------------------+-------------------+
|MT-Level | MT-Safe |
+--------------------+-------------------+
|Standard | See standards(7). |
+--------------------+-------------------+

SEE ALSO

msgctl(2), msgget(2), msgrcv(2), msgsnd(2), mq_getattr(3C), mq_open(3C),
mq_receive(3C), mq_send(3C), mqueue.h(3HEAD), attributes(7), standards(7)

NOTES

Solaris 2.6 was the first release to support the Asynchronous Input and
Output option. Prior to this release, this function always returned -1
and set errno to ENOSYS.


February 5, 2008 MQ_SETATTR(3C)