1.\" $NetBSD: getpgrp.2,v 1.17 2002/02/08 01:28:17 ross 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 39.Sh NAME 40.Nm getpgrp , 41.Nm getpgid 42.Nd get process group 43.Sh LIBRARY 44.Lb libc 45.Sh SYNOPSIS 46.Fd #include \*[Lt]unistd.h\*[Gt] 47.Ft pid_t 48.Fn getpgrp "void" 49.Ft pid_t 50.Fn getpgid "pid_t pid" 51.Sh DESCRIPTION 52The process group of the current process is returned by 53.Fn getpgrp . 54The process group of the 55.Fa pid 56process is returned by 57.Fn getpgid . 58.Pp 59Process groups are used for distribution of signals, and 60by terminals to arbitrate requests for their input: processes 61that have the same process group as the terminal are foreground 62and may read, while others will block with a signal if they attempt 63to read. 64.Pp 65This call is thus used by programs such as 66.Xr csh 1 67to create 68process groups 69in implementing job control. 70The 71.Fn tcgetpgrp 72and 73.Fn tcsetpgrp 74calls 75are used to get/set the process group of the control terminal. 76.Sh SEE ALSO 77.Xr setpgid 2 , 78.Xr termios 4 79.Sh STANDARDS 80The 81.Fn getpgrp 82function conforms to 83.St -p1003.1-88 . 84.Sh HISTORY 85The 86.Fn getpgrp 87function call appeared in 88.Bx 4.0 . 89The 90.Fn getpgid 91function call is derived from its usage in 92.At V.4 , 93and first appeared in 94.Nx 1.3 . 95.Sh COMPATIBILITY 96This version of 97.Fn getpgrp 98differs from past Berkeley versions by not taking a 99.Fa "pid_t pid" 100argument. 101This incompatibility is required by 102.St -p1003.1-90 . 103.Pp 104From the 105.St -p1003.1-90 106Rationale: 107.sp 108.Bx 4.3 109provides a 110.Fn getpgrp 111function that returns the process group ID for a specified process. 112Although this function is used to support job control, all known 113job-control shells always specify the calling process with this 114function. 115Thus, the simpler System V 116.Fn getpgrp 117suffices, and the added complexity of the 118.Bx 4.3 119.Fn getpgrp 120has been omitted from POSIX.1. 121The old functionality is available from the 122.Fn getpgid 123function. 124