mq_setattr(3c)

NAME
     mq_setattr - set attributes of a message queue

C SYNOPSIS
     #include <mqueue.h>

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

DESCRIPTION
     mq_setattr sets the attributes, specified in the mq_attr structure
     pointed to by mqstat, of the message queue described by mqd.  The
     attributes of the queue specified by the following fields of the mq_attr
     structure are updated after a successful call to mq_setattr:

     mq_flags  If the O_NONBLOCK flag is set, then the mq_send and mq_receive
               functions do not block when operating on the mqd queue
               descriptor.  Other queue descriptors referring to the same
               message queue are not affected.

     The values of all the other members of the mq_attr structure, pointed to
     by mqstat are ignored by mq_setattr.

     If omqstat is non-NULL, the previous message queue attributes are stored
     in the mq_attr structure pointed to by omqstat. The attributes stored in
     the mq_attr structure are the same as those retrieved by mq_getattr.

     mq_setattr will fail if one or more of the following conditions are true:

     [EBADF]        The message queue descriptor, mqd, is not valid.

     [EINTR]        A signal interrupted the mq_setattr function call.

SEE ALSO
     mq_open(3c), intro(3c), mq_unlink(3c), mq_receive(3c), mq_send(3c),
     mq_getattr(3c), mq_notify(3c),

DIAGNOSTICS
     Upon successful completion, a value of 0 is returned and the attributes
     of the message queue are changed as specified.  Otherwise, a value of -1
     is returned and errno is set to indicate the error.