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Diffstat (limited to 'lib/libc/sys/msgget.2')
-rw-r--r-- | lib/libc/sys/msgget.2 | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/lib/libc/sys/msgget.2 b/lib/libc/sys/msgget.2 new file mode 100644 index 0000000..27e1766 --- /dev/null +++ b/lib/libc/sys/msgget.2 @@ -0,0 +1,141 @@ +.\" $NetBSD: msgget.2,v 1.1 1995/10/16 23:49:19 jtc Exp $ +.\" +.\" Copyright (c) 1995 Frank van der Linden +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed for the NetBSD Project +.\" by Frank van der Linden +.\" 4. The name of the author may not be used to endorse or promote products +.\" derived from this software without specific prior written permission +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR +.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES +.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. +.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, +.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT +.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF +.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +.\" $FreeBSD$ +.\" +.\"/ +.Dd July 9, 2009 +.Dt MSGGET 2 +.Os +.Sh NAME +.Nm msgget +.Nd get message queue +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In sys/types.h +.In sys/ipc.h +.In sys/msg.h +.Ft int +.Fn msgget "key_t key" "int msgflg" +.Sh DESCRIPTION +The +.Fn msgget +function +returns the message queue identifier associated with +.Fa key . +A message queue identifier is a unique integer greater than zero. +.Pp +A message queue is created if either +.Fa key +is equal to +.Dv IPC_PRIVATE , +or +.Fa key +does not have a message queue identifier associated with it, and the +.Dv IPC_CREAT +bit is set in +.Fa msgflg . +.Pp +If a new message queue is created, the data structure associated with it (the +.Va msqid_ds +structure, see +.Xr msgctl 2 ) +is initialized as follows: +.Bl -bullet +.It +.Va msg_perm.cuid +and +.Va msg_perm.uid +are set to the effective uid of the calling process. +.It +.Va msg_perm.gid +and +.Va msg_perm.cgid +are set to the effective gid of the calling process. +.It +.Va msg_perm.mode +is set to the lower 9 bits of +.Fa msgflg . +.It +.Va msg_cbytes , +.Va msg_qnum , +.Va msg_lspid , +.Va msg_lrpid , +.Va msg_rtime , +and +.Va msg_stime +are set to 0. +.It +.Va msg_qbytes +is set to the system wide maximum value for the number of bytes in a queue +.Pf ( Dv MSGMNB ) . +.It +.Va msg_ctime +is set to the current time. +.El +.Sh RETURN VALUES +Upon successful completion a positive message queue identifier is returned. +Otherwise, -1 is returned and the global variable +.Va errno +is set to indicate the error. +.Sh ERRORS +.Bl -tag -width Er +.It Bq Er EACCES +A message queue is already associated with +.Fa key +and the caller has no permission to access it. +.It Bq Er EEXIST +Both +.Dv IPC_CREAT +and +.Dv IPC_EXCL +are set in +.Fa msgflg , +and a message queue is already associated with +.Fa key . +.It Bq Er ENOSPC +A new message queue could not be created because the system limit for +the number of message queues has been reached. +.It Bq Er ENOENT +.Dv IPC_CREAT +was not set in +.Fa msgflg +and no message queue associated with +.Fa key +was found. +.El +.Sh SEE ALSO +.Xr msgctl 2 , +.Xr msgrcv 2 , +.Xr msgsnd 2 +.Sh HISTORY +Message queues appeared in the first release of +.At V . |