1.\" $NetBSD: getpgrp.2,v 1.12 1997/11/12 00:47:32 mrg Exp $ 2.\" 3.\" Copyright (c) 1983, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)getpgrp.2 8.1 (Berkeley) 6/4/93 35.\" 36.Dd June 4, 1993 37.Dt GETPGRP 2 38.Os BSD 4.2 39.Sh NAME 40.Nm getpgrp , 41.Nm getpgid 42.Nd get process group 43.Sh SYNOPSIS 44.Fd #include <unistd.h> 45.Ft pid_t 46.Fn getpgrp "void" 47.Ft pid_t 48.Fn getpgid "pid_t pid" 49.Sh DESCRIPTION 50The process group of the current process is returned by 51.Fn getpgrp . 52The process group of the 53.Fa pid 54process is returned by 55.Fn getpgid . 56.Pp 57Process groups are used for distribution of signals, and 58by terminals to arbitrate requests for their input: processes 59that have the same process group as the terminal are foreground 60and may read, while others will block with a signal if they attempt 61to read. 62.Pp 63This call is thus used by programs such as 64.Xr csh 1 65to create 66process groups 67in implementing job control. 68The 69.Fn tcgetpgrp 70and 71.Fn tcsetpgrp 72calls 73are used to get/set the process group of the control terminal. 74.Sh SEE ALSO 75.Xr setpgid 2 , 76.Xr termios 4 77.Sh STANDARDS 78The 79.Fn getpgrp 80function conforms to 81.St -p1003.1-88 . 82.Sh HISTORY 83The 84.Fn getpgrp 85function call appeared in 86.Bx 4.0 . 87The 88.Fn getpgid 89function call is derived from it's usage in System V Release 4, and 90first appeared in NetBSD 1.2A. 91.Sh COMPATIBILITY 92This version of 93.Fn getpgrp 94differs from past Berkeley versions by not taking a 95.Fa "pid_t pid" 96argument. 97This incompatibility is required by 98.St -p1003.1-90 . 99.Pp 100From the 101.St -p1003.1-90 102Rationale: 103.sp 1044.3BSD provides a 105.Fn getpgrp 106function that returns the process group ID for a specified process. 107Although this function is used to support job control, all known 108job-control shells always specify the calling process with this 109function. 110Thus, the simpler System V 111.Fn getpgrp 112suffices, and the added complexity of the 4.3BSD 113.Fn getpgrp 114has been omitted from POSIX.1. 115The old functionality is available from the 116.Fn getpgid 117function. 118