mq_getattr

Langue: en

Version: DECEMBER 2002 (mandriva - 01/05/08)

Autres sections - même nom

Section: 2 (Appels système)

NAME

mq_getattr - get message queue attributes

SYNOPSIS

gcc [ flag... ] file ... -lmqueue [ library... ]

#include <mqueue.h>

int mq_getattr(mqd_t mqdes, struct mq_attr *mqstat);

DESCRIPTION

The mq_getattr() function is used to get status information and attributes of the message queue and the open message queue description associated with the message queue descriptor.

The mqdes argument specifies a message queue descriptor.

The results are returned in the mq_attr structure referenced by the mqstat argument.

Upon return, the following members will have the values associated with the open message queue description as set when the message queue was opened and as modified by subsequent mq_setattr() calls:

mq_flags
message queue flags

The following attributes of the message queue are returned as set at message queue creation:

mq_maxmsg
maximum number of messages
mq_msgsize
maximum message size

The following members within the mq_attr structure referenced by the mqstat argument will be set to the current state of the message queue:

mq_curmsgs
the number of messages currently on the queue.

RETURN VALUES

Upon successful completion, mq_getattr() returns 0; otherwise, the function returns -1 and sets errno to indicate the error condition.

DIAGNOSTICS

The mq_getattr() function will fail if:
EBADF
The mqdes argument is not a valid message queue descriptor.
EINVAL
The mqstat argument is set to NULL.
EFAULT
mqstat points outside your accessible address space.

AUTHORS

Krzysztof Benedyczak <golbi@mat.uni.torun.pl>
Michal Wronski <wrona@mat.uni.torun.pl>

CONFORMING TO

IEEE Std 1003.1-2001

SEE ALSO

mq_setattr(2) mq_open(2)