1.\" $NetBSD: getpgrp.2,v 1.11 1997/09/09 07:26:04 jtc 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.Nd get process group 42.Sh SYNOPSIS 43.Fd #include <unistd.h> 44.Ft pid_t 45.Fn getpgrp "void" 46.Ft pid_t 47.Fn getpgid "pid_t pid" 48.Sh DESCRIPTION 49The process group of the current process is returned by 50.Fn getpgrp . 51The process group of the 52.Fa pid 53process is returned by 54.Fn getpgid . 55.Pp 56Process groups are used for distribution of signals, and 57by terminals to arbitrate requests for their input: processes 58that have the same process group as the terminal are foreground 59and may read, while others will block with a signal if they attempt 60to read. 61.Pp 62This call is thus used by programs such as 63.Xr csh 1 64to create 65process groups 66in implementing job control. 67The 68.Fn tcgetpgrp 69and 70.Fn tcsetpgrp 71calls 72are used to get/set the process group of the control terminal. 73.Sh SEE ALSO 74.Xr setpgid 2 , 75.Xr termios 4 76.Sh STANDARDS 77The 78.Fn getpgrp 79function conforms to 80.St -p1003.1-88 . 81.Sh HISTORY 82The 83.Fn getpgrp 84function call appeared in 85.Bx 4.0 . 86The 87.Fn getpgid 88function call is derived from it's usage in System V Release 4, and 89first appeared in NetBSD 1.2A. 90.Sh COMPATIBILITY 91This version of 92.Fn getpgrp 93differs from past Berkeley versions by not taking a 94.Fa "pid_t pid" 95argument. 96This incompatibility is required by 97.St -p1003.1-90 . 98.Pp 99From the 100.St -p1003.1-90 101Rationale: 102.sp 1034.3BSD provides a 104.Fn getpgrp 105function that returns the process group ID for a specified process. 106Although this function is used to support job control, all known 107job-control shells always specify the calling process with this 108function. 109Thus, the simpler System V 110.Fn getpgrp 111suffices, and the added complexity of the 4.3BSD 112.Fn getpgrp 113has been omitted from POSIX.1. 114The old functionality is available from the 115.Fn getpgid 116function. 117