Return to msgctl.3l CVS log

Up to [Research Unix] / researchv10dc / 630 / man / src / p_man / man3

researchv10 Dan Cross

.TH MSGCTL 3L "630 MTG"
.XE "msgctl()"
.SH NAME
msgctl \- message control operations
.SH SYNOPSIS
.B #include <message.h>
.sp
.B int msgctl (msqid, cmd, buf)
.br
.B long msqid;
.br
.B int cmd;
.br
.B struct msqid_ds \(**buf;
.SH DESCRIPTION
.I Msgctl
provides a variety of message control operations as
specified by
.IR cmd.
The following
.I cmds
are available:
.sp
.B IPC_STAT
.br
.RS 6
Place the current value of each member of the
data structure associated with
.I msqid
into the structure pointed to by
.IR buf .
.RE
.PP
.B IPC_SET
.br
.RS 6
Set the value of the following members of the
data structure associated with
.I msqid
to the corresponding value found in the structure
pointed to by
.IR buf:
.ft B
.RS 6
msg_qbytes
.br
cid
.br
state
.ft R
.sp
.RE
The creator process id can be changed.
This is done so that when this
process is deleted, the queue will be deleted with it.
.RE
.PP
.B IPC_RMID
.br
.RS 6
Remove the message queue identifier specified by
.I msqid
from the system and destroy the
message queue and data structure associated
with it. This can be executed by any process.
.RE
.PP
.I Msgctl
will fail if one or more of the following are true:
.sp
.RS 6
.I Msqid
is not a valid message queue identifier.
.sp
.I Cmd
is not a valid command.
.sp
.I Cmd
is equal to
.B IPC_SET
and an attempt is being made to increase the value of
.B msg_qbytes
over
.B MAX_BYTES
(8192).
.RE
.P
A side effect of \f2msgctl\f1 is that it clears the MSG
resource ready condition used by the \f2wait\f1 and \f2own\f1
resource functions.
.SS Return Value
Upon successful completion, a value of 0 is returned.
Otherwise, a value of -1 is returned.
.PP
.SH SEE ALSO
msgget(3L), msgop(3L), realtime(3R), resources(3R), structures(3R).

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.