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

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

       msglen_t      Used for the number of bytes allowed in a message

       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>

       The following sections are informative.



RATIONALE         top




SEE ALSO         top

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

       The System Interfaces volume of POSIX.1‐2008, 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, 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 .

       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 .

IEEE/The Open Group                 2013                       sys_msg.h(0P)