msgget(2) [sunos man page]

msgget(2)							   System Calls 							 msgget(2)

NAME

       msgget - get message queue

SYNOPSIS

       #include <sys/msg.h>

       int msgget(key_t key, int msgflg);

DESCRIPTION

       The msgget() argument returns the message queue identifier associated with key.

       A  message  queue identifier and associated message queue and data structure (see intro(2)) are created for key if one of the following are
       true:

	 o  key is IPC_PRIVATE.

	 o  key does not already have a message queue identifier associated with it, and (msgflg&IPC_CREAT) is true.

       On creation, the data structure associated with the new message queue identifier is initialized as follows:

	 o  msg_perm.cuid, msg_perm.uid, msg_perm.cgid, and msg_perm.gid are set to the effective user ID and effective group ID, respectively, of
	    the calling process.

	 o  The low-order 9 bits of msg_perm.mode are set to the low-order 9 bits of msgflg.

	 o  msg_qnum, msg_lspid, msg_lrpid, msg_stime, and msg_rtime are set to 0.

	 o  msg_ctime is set to the current time.

	 o  msg_qbytes is set to the system limit. See NOTES.

RETURN VALUES

       Upon successful completion, a non-negative integer representing a message queue identifier is returned. Otherwise, -1 is returned and errno
       is set to indicate the error.

ERRORS

       The msgget() function will fail if:

       EACCES	       A message queue identifier exists for key, but operation permission (see intro(2)) as specified by the low-order 9 bits	of
		       msgflg would not be granted.

       EEXIST	       A message queue identifier exists for key but (msgflg&IPC_CREAT) and (msgflg&IPC_EXCL) are both true.

       ENOENT	       A message queue identifier does not exist for key and (msgflg&IPC_CREAT) is false.

       ENOSPC	       A  message  queue  identifier  is to be created but the system-imposed limit on the maximum number of allowed message queue
		       identifiers system wide would be exceeded. See NOTES.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       rctladm(1M), intro(2), msgctl(2), msgrcv(2), msgsnd(2), setrctl(2), ftok(3C), attributes(5), standards(5)

NOTES

       The system-defined limit used to initialize msg_qbytes is the minimum  enforced	value  of  the	calling  process's  process.max-msg-qbytes
       resource control.

       The  system-imposed  limit  on  the  number of message queue identifiers is maintained on a per-project basis using the project.max-msg-ids
       resource control.

	See rctladm(1M) and setrctl(2) for information about using resource controls.

SunOS 5.10							    11 Feb 2003 							 msgget(2)

Check Out this Related Man Page

MSGGET(2)						      BSD System Calls Manual							 MSGGET(2)

NAME

     msgget -- get message queue identifier

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <sys/msg.h>

     int
     msgget(key_t key, int msgflg);

DESCRIPTION

     The msgget() system call returns the message queue identifier associated with key.  A message queue identifier is a unique integer greater
     than zero.

     A message queue is created if either key is equal to IPC_PRIVATE, or key does not have a message queue identifier associated with it and the
     IPC_CREAT bit is set in msgflg.  If both the IPC_CREAT bit and the IPC_EXCL bit are set in msgflg, and key has a message queue identifier
     associated with it already, the operation will fail.

     If a new message queue is created, the data structure associated with it (the msqid_ds structure, see msgctl(2)) is initialized as follows:

     o	 msg_perm.cuid and msg_perm.uid are set to the effective uid of the calling process.

     o	 msg_perm.gid and msg_perm.cgid are set to the effective gid of the calling process.

     o	 msg_perm.mode is set to the lower 9 bits of msgflg.

     o	 msg_qnum, msg_lspid, msg_lrpid, msg_rtime, and msg_stime are set to 0.

     o	 msg_qbytes is set to the system wide maximum value for the number of bytes in a queue (MSGMNB).

     o	 msg_ctime is set to the current time.

RETURN VALUES

     Upon successful completion a positive message queue identifier is returned.  Otherwise, -1 is returned and the global variable errno is set
     to indicate the error.

ERRORS

     [EACCES]		A message queue is already associated with key and the caller has no permission to access it.

     [EEXIST]		Both IPC_CREAT and IPC_EXCL are set in msgflg, and a message queue is already associated with key.

     [ENOSPC]		A new message queue could not be created because the system limit for the number of message queues has been reached.

     [ENOENT]		IPC_CREAT is not set in msgflg and no message queue associated with key was found.

SEE ALSO

     msgctl(2), msgrcv(2), msgsnd(2), ftok(3)

STANDARDS

     The msgget system call conforms to X/Open System Interfaces and Headers Issue 5 (``XSH5'').

HISTORY

     Message queues appeared in the first release of AT&T System V UNIX.

BSD
								   May 13, 2004 							       BSD

Linux and UNIX Man Pages

msgget(2) [sunos man page]

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