1mqueue.h(0P) POSIX Programmer's Manual mqueue.h(0P)
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6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
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12 mqueue.h — message queues (REALTIME)
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15 #include <mqueue.h>
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18 The <mqueue.h> header shall define the mqd_t type, which is used for
19 message queue descriptors. This is not an array type.
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21 The <mqueue.h> header shall define the pthread_attr_t, size_t, and
22 ssize_t types as described in <sys/types.h>.
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24 The <mqueue.h> header shall define the struct timespec structure as
25 described in <time.h>.
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27 The tag sigevent shall be declared as naming an incomplete structure
28 type, the contents of which are described in the <signal.h> header.
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30 The <mqueue.h> header shall define the mq_attr structure, which is used
31 in getting and setting the attributes of a message queue. Attributes
32 are initially set when the message queue is created. An mq_attr struc‐
33 ture shall have at least the following fields:
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36 long mq_flags Message queue flags.
37 long mq_maxmsg Maximum number of messages.
38 long mq_msgsize Maximum message size.
39 long mq_curmsgs Number of messages currently queued.
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41 The following shall be declared as functions and may also be defined as
42 macros. Function prototypes shall be provided.
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45 int mq_close(mqd_t);
46 int mq_getattr(mqd_t, struct mq_attr *);
47 int mq_notify(mqd_t, const struct sigevent *);
48 mqd_t mq_open(const char *, int, ...);
49 ssize_t mq_receive(mqd_t, char *, size_t, unsigned *);
50 int mq_send(mqd_t, const char *, size_t, unsigned);
51 int mq_setattr(mqd_t, const struct mq_attr *restrict,
52 struct mq_attr *restrict);
53 ssize_t mq_timedreceive(mqd_t, char *restrict, size_t,
54 unsigned *restrict, const struct timespec *restrict);
55 int mq_timedsend(mqd_t, const char *, size_t, unsigned,
56 const struct timespec *);
57 int mq_unlink(const char *);
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59 Inclusion of the <mqueue.h> header may make visible symbols defined in
60 the headers <fcntl.h>, <signal.h>, and <time.h>.
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62 The following sections are informative.
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65 None.
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68 None.
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71 None.
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74 <fcntl.h>, <signal.h>, <sys_types.h>, <time.h>
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76 The System Interfaces volume of POSIX.1‐2017, mq_close(), mq_getattr(),
77 mq_notify(), mq_open(), mq_receive(), mq_send(), mq_setattr(),
78 mq_unlink()
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81 Portions of this text are reprinted and reproduced in electronic form
82 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
83 table Operating System Interface (POSIX), The Open Group Base Specifi‐
84 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
85 Electrical and Electronics Engineers, Inc and The Open Group. In the
86 event of any discrepancy between this version and the original IEEE and
87 The Open Group Standard, the original IEEE and The Open Group Standard
88 is the referee document. The original Standard can be obtained online
89 at http://www.opengroup.org/unix/online.html .
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91 Any typographical or formatting errors that appear in this page are
92 most likely to have been introduced during the conversion of the source
93 files to man page format. To report such errors, see https://www.ker‐
94 nel.org/doc/man-pages/reporting_bugs.html .
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98IEEE/The Open Group 2017 mqueue.h(0P)