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Command: mq_getattr | Section: 3 | Source: Digital UNIX | File: mq_getattr.3.gz
mq_getattr(3) Library Functions Manual mq_getattr(3)
NAME
mq_getattr - Returns the status and attributes of a message queue
(P1003.1b)
SYNOPSIS
#include <mqueue.h>
int mq_getattr (
mqd_t mqdes,
struct mq_attr *mqstat);
PARAMETERS
mqdes Specifies the message queue descriptor whose attributes are ob-
tained.
*mqstat A pointer a structure that is updated to contain the values
that were set when the message queue was created or modified by
a call to the mq_setattr function.
When the mq_getattr function returns, the following three members of
the mq_attr structure specified by mqstat will have the values that
were set when the message queue was created, but with modifications
made by subsequent calls to the mq_setattr function:
o The mq_maxmsg member specifies the maximum number of messages
that can be held in the queue specified by the mqdes argument.
o The mq_msgsize member specifies the maximum size of any message
in the queue.
o The mq_flags member specifies whether the message operation is
blocking or nonblocking (MQ_NONBLOCK).
The mq_curmsgs member of the mq_attr structure indicates the number of
messages currently on the queue.
DESCRIPTION
Returns the status and attributes of a message queue. Use the mq_se-
tattr function to set message queue attributes.
RETURN VALUES
On successful completion, the function returns the value 0; otherwise,
the function returns the value -1 and sets errno to indicate the error.
ERRORS
The mq_getattr function fails under the following conditions:
[EBADF] The fildes argument is an invalid file descriptor.
[EINVAL] The mqstat argument is a null pointer.
RELATED INFORMATION
Functions: mq_open(3), mq_receive(3), mq_send(3), mq_setattr(3) delim
off
mq_getattr(3)