Content-type: text/html Man page of mq_getattr

mq_getattr

Section: C Library Functions (3)
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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 obtained.
*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:

The mq_maxmsg member specifies the maximum number of messages that can be held in the queue specified by the mqdes argument.
The mq_msgsize member specifies the maximum size of any message in the queue.
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_setattr 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


 

Index

NAME
SYNOPSIS
PARAMETERS
DESCRIPTION
RETURN VALUES
ERRORS
RELATED INFORMATION

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Time: 02:41:57 GMT, October 02, 2010