1.\" $NetBSD: _exit.2,v 1.20 2022/10/18 07:33:15 wiz Exp $ 2.\" 3.\" Copyright (c) 1980, 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. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)_exit.2 8.1 (Berkeley) 6/4/93 31.\" 32.Dd October 17, 2022 33.Dt EXIT 2 34.Os 35.Sh NAME 36.Nm _Exit, _exit 37.Nd terminate the calling process 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In stdlib.h 42.Ft void 43.Fn _Exit "int status" 44.In unistd.h 45.Ft void 46.Fn _exit "int status" 47.Sh DESCRIPTION 48The 49.Fn _Exit 50and 51.Fn _exit 52functions are equivalent. 53They each terminate a process with the following consequences: 54.Bl -bullet 55.It 56All of the descriptors open in the calling process are closed. 57This may entail delays, for example, waiting for output to drain; 58a process in this state may not be killed, as it is already dying. 59.It 60If the parent process of the calling process has an outstanding 61.Xr wait 2 62call 63or catches the 64.Dv SIGCHLD 65signal, 66it is notified of the calling process's termination and 67the 68.Em status 69is set as defined by 70.Xr wait 2 . 71(Note that only the least significant 8 bits of 72.Em status 73are preserved and returned to the parent via 74.Xr wait 2 . ) 75.It 76The parent process-ID of all of the calling process's existing child 77processes are set to 1; the initialization process 78(see the DEFINITIONS section of 79.Xr intro 2 ) 80inherits each of these processes. 81.It 82If the termination of the process causes any process group 83to become orphaned (usually because the parents of all members 84of the group have now exited; see 85.Dq orphaned process group 86in 87.Xr intro 2 ) , 88and if any member of the orphaned group is stopped, 89the 90.Dv SIGHUP 91signal and the 92.Dv SIGCONT 93signal are sent to all members of the newly-orphaned process group. 94.It 95If the process is a controlling process (see 96.Xr intro 2 ) , 97the 98.Dv SIGHUP 99signal is sent to the foreground process group of the controlling terminal, 100and all current access to the controlling terminal is revoked. 101.El 102.Pp 103Most C programs call the library routine 104.Xr exit 3 , 105which flushes buffers, closes streams, unlinks temporary files, etc., 106before 107calling 108.Fn _exit . 109.Sh RETURN VALUES 110.Fn _Exit 111and 112.Fn _exit 113can never return. 114.Sh SEE ALSO 115.Xr fork 2 , 116.Xr sigaction 2 , 117.Xr wait 2 , 118.Xr exit 3 119.Sh STANDARDS 120The 121.Fn _exit 122function conforms to 123.St -p1003.1-90 . 124The 125.Fn _Exit 126function conforms to 127.St -isoC-99 . 128