.\" Copyright (c) 1983, 1991 Regents of the University of California. .\" 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 by the University of .\" California, Berkeley and its contributors. .\" 4. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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. .\" .\" @(#)getpgrp.2 6.4 (Berkeley) 3/10/91 .\" .\" Modified Sat Jul 24 01:15:33 1993 by Rik Faith .\" Modified 15 April 1995 by Michael Chastain : .\" Added 'getpgid'. .\" Modified 21 July 1996 by Andries Brouwer .\" Modified Wed Nov 6 04:02:50 1996 by Eric S. Raymond .\" FIXME -- error conditions need to be better documented, see kernel .\" .TH SETPGID 2 "15 April 1995" "Linux 1.2.4" "Linux Programmer's Manual" .SH NAME setpgid, getpgid, setpgrp, getpgrp \- set/get process group .SH SYNOPSIS .B #include .sp .BI "int setpgid(pid_t " pid ", pid_t " pgid ); .br .BI "pid_t getpgid(pid_t " pid ); .br .B int setpgrp(void); .br .B pid_t getpgrp(void); .SH DESCRIPTION .B setpgid sets the process group ID of the process specified by .I pid to .IR pgid . If .I pid is zero, the process ID of the current process is used. If .I pgid is zero, the process ID of the process specified by .I pid is used. .B getpgid returns the process group ID of the process specified by .IR pid . If .I pid is zero, the process ID of the current process is used. In the Linux DLL 4.4.1 library, .B setpgrp simply calls .BR setpgid(0,0) . .B getpgrp is equivalent to .BR getpgid(0) . Process groups are used for distribution of signals, and by terminals to arbitrate requests for their input: processes that have the same process group as the terminal are foreground and may read, while others will block with a signal if they attempt to read. These calls are thus used by programs such as .BR csh (1) to create process groups in implementing job control. The .B TIOCGPGRP and .B TIOCSPGRP calls described in .BR termios (4) are used to get/set the process group of the control terminal. .SH "RETURN VALUE" On success, .BR setpgid " and " setpgrp return zero. On error, \-1 is returned, and .I errno is set appropriately. .I getpgid returns a process group on success. On error, \-1 is returned, and .I errno is set appropriately. .I getpgrp always returns the current process group. .SH ERRORS .TP 0.8i .B EINVAL .I pgid is less than 0. .TP .B EPERM Various permission violations. .TP .B ESRCH .I pid does not match any process. .SH "CONFORMING TO" SVr4, POSIX, 4.4BSD. .SH "CONFORMING TO" The functions .B setpgid and .B getpgrp conform to POSIX.1. The function .B setpgrp is from BSD 4.2. The function .BR getpgid conforms to SVr4. .SH "SEE ALSO" .BR getuid "(2), " setsid "(2), " tcsetpgrp "(3), " termios (4)