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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