This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the corresponding Linux
manual page for details of Linux behavior), or the interface may not be
implemented on Linux.
mqueue.h — message queues ( REALTIME
header shall define the mqd_t
type, which is
used for message queue descriptors. This is not an array type.
header shall define the pthread_attr_t
, and ssize_t
types as described in
header shall define the struct timespec
structure as described in <time.h>
The tag sigevent
shall be declared as naming an incomplete structure
type, the contents of which are described in the <signal.h>
header shall define the mq_attr
which is used in getting and setting the attributes of a message queue.
Attributes are initially set when the message queue is created. An
structure shall have at least the following fields:
long mq_flags Message queue flags.
long mq_maxmsg Maximum number of messages.
long mq_msgsize Maximum message size.
long mq_curmsgs Number of messages currently queued.
The following shall be declared as functions and may also be defined as macros.
Function prototypes shall be provided.
int mq_getattr(mqd_t, struct mq_attr *);
int mq_notify(mqd_t, const struct sigevent *);
mqd_t mq_open(const char *, int, ...);
ssize_t mq_receive(mqd_t, char *, size_t, unsigned *);
int mq_send(mqd_t, const char *, size_t, unsigned);
int mq_setattr(mqd_t, const struct mq_attr *restrict,
struct mq_attr *restrict);
ssize_t mq_timedreceive(mqd_t, char *restrict, size_t,
unsigned *restrict, const struct timespec *restrict);
int mq_timedsend(mqd_t, const char *, size_t, unsigned,
const struct timespec *);
int mq_unlink(const char *);
Inclusion of the <mqueue.h>
header may make visible symbols defined
in the headers <fcntl.h>
The following sections are informative.
The System Interfaces volume of POSIX.1‐2008, mq_close()
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2013 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
7, Copyright (C) 2013 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. (This is POSIX.1-2008 with the 2013
Technical Corrigendum 1 applied.) In the event of any discrepancy between this
version and the original IEEE and The Open Group Standard, the original IEEE
and The Open Group Standard is the referee document. The original Standard can
be obtained online at http://www.unix.org/online.html .
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