#include <mqueue.h>
The <mqueue.h> header shall define the pthread_attr_t, size_t, and ssize_t types as described in <sys/types.h>.
The <mqueue.h> 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.
The <mqueue.h> header shall define the mq_attr structure, which is used in getting and setting the attributes of a message queue. Attributes are initially set when the message queue is created. An mq_attr 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_close(mqd_t);
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>, <signal.h>, and <time.h>.
The following sections are informative.
The System Interfaces volume of POSIX.1-2017, mq_close(), mq_getattr(), mq_notify(), mq_open(), mq_receive(), mq_send(), mq_setattr(), mq_unlink()
Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .