1.\" Copyright (c) 1990, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the American National Standards Committee X3, on Information 6.\" Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)exit.3 8.1 (Berkeley) 6/4/93 33.\" 34.Dd August 5, 2021 35.Dt EXIT 3 36.Os 37.Sh NAME 38.Nm exit , _Exit 39.Nd perform normal program termination 40.Sh LIBRARY 41.Lb libc 42.Sh SYNOPSIS 43.In stdlib.h 44.Ft void 45.Fn exit "int status" 46.Ft void 47.Fn _Exit "int status" 48.Sh DESCRIPTION 49The 50.Fn exit 51and 52.Fn _Exit 53functions terminate a process. 54.Pp 55Before termination, 56.Fn exit 57performs the following functions in the order listed: 58.Bl -enum -offset indent 59.It 60Call all functions registered with the 61.Xr __cxa_atexit 3 62function 63(which are typically destructors from the loaded dynamic objects), 64and the functions registered with the 65.Xr atexit 3 66function, in the reverse order of their registration. 67.It 68Flush all open output streams. 69.It 70Close all open streams. 71.El 72.Pp 73The 74.Fn _Exit 75function terminates without calling the functions registered with the 76.Xr atexit 3 77function, and may or may not perform the other actions listed. 78The 79.Fx 80implementation of the 81.Fn _Exit 82function does not call destructors registered with 83.Xr __cxa_atexit 3, 84does not flush buffers, and does not close streams. 85.Pp 86Both functions make the low-order eight bits of the 87.Fa status 88argument available to a parent process which has called a 89.Xr wait 2 Ns -family 90function. 91.Pp 92The C Standard 93.Pq St -isoC-99 94defines the values 95.Li 0 , 96.Dv EXIT_SUCCESS , 97and 98.Dv EXIT_FAILURE 99as possible values of 100.Fa status . 101Cooperating processes may use other values; 102in a program which might be called by a mail transfer agent, the 103values described in 104.Xr sysexits 3 105may be used to provide more information to the parent process. 106.Pp 107Note that 108.Fn exit 109does nothing to prevent bottomless recursion should a function registered 110using 111.Xr atexit 3 112itself call 113.Fn exit . 114Such functions must call 115.Fn _Exit 116instead (although this has other effects as well which may not be desired). 117.Sh RETURN VALUES 118The 119.Fn exit 120and 121.Fn _Exit 122functions 123never return. 124.Sh SEE ALSO 125.Xr _exit 2 , 126.Xr abort2 2 , 127.Xr wait 2 , 128.Xr at_quick_exit 3 , 129.Xr atexit 3 , 130.Xr intro 3 , 131.Xr quick_exit 3 , 132.Xr sysexits 3 , 133.Xr tmpfile 3 134.Sh STANDARDS 135The 136.Fn exit 137and 138.Fn _Exit 139functions conform to 140.St -isoC-99 . 141.Sh HISTORY 142The 143.Fn exit 144function appeared in 145.At v1 . 146