sys_msg.h(0p) — Linux manual page

PROLOG | NAME | SYNOPSIS | DESCRIPTION | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

sys_msg.h(0P)           POSIX Programmer's Manual          sys_msg.h(0P)

PROLOG         top

       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.

NAME         top

       sys/msg.h — XSI message queue structures

SYNOPSIS         top

       #include <sys/msg.h>

DESCRIPTION         top

       The <sys/msg.h> header shall define the following data types
       through typedef:

       msgqnum_t     Used for the number of messages in the message
                     queue.

       msglen_t      Used for the number of bytes allowed in a message
                     queue.

       These types shall be unsigned integer types that are able to
       store values at least as large as a type unsigned short.

       The <sys/msg.h> header shall define the following symbolic
       constant as a message operation flag:

       MSG_NOERROR   No error if big message.

       The <sys/msg.h> header shall define the msqid_ds structure, which
       shall include the following members:

           struct ipc_perm msg_perm   Operation permission structure.
           msgqnum_t       msg_qnum   Number of messages currently on queue.
           msglen_t        msg_qbytes Maximum number of bytes allowed on queue.
           pid_t           msg_lspid  Process ID of last msgsnd().
           pid_t           msg_lrpid  Process ID of last msgrcv().
           time_t          msg_stime  Time of last msgsnd().
           time_t          msg_rtime  Time of last msgrcv().
           time_t          msg_ctime  Time of last change.

       The <sys/msg.h> header shall define the pid_t, size_t, ssize_t,
       and time_t types as described in <sys/types.h>.

       The following shall be declared as functions and may also be
       defined as macros. Function prototypes shall be provided.

           int       msgctl(int, int, struct msqid_ds *);
           int       msgget(key_t, int);
           ssize_t   msgrcv(int, void *, size_t, long, int);
           int       msgsnd(int, const void *, size_t, int);

       In addition, the <sys/msg.h> header shall include the <sys/ipc.h>
       header.

       The following sections are informative.

APPLICATION USAGE         top

       None.

RATIONALE         top

       None.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       sys_ipc.h(0p), sys_types.h(0p)

       The System Interfaces volume of POSIX.1‐2017, msgctl(3p),
       msgget(3p), msgrcv(3p), msgsnd(3p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 by the Institute of Electrical and Electronics
       Engineers, Inc and The Open Group.  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.opengroup.org/unix/online.html .

       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 .

IEEE/The Open Group               2017                     sys_msg.h(0P)

Pages that refer to this page: msgctl(3p)msgget(3p)msgrcv(3p)msgsnd(3p)