1.\" $NetBSD: atexit.3,v 1.11 2013/04/26 19:37:04 wiz Exp $ 2.\" 3.\" Copyright (c) 1990, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" This code is derived from software contributed to Berkeley by 7.\" Chris Torek and the American National Standards Committee X3, 8.\" on Information Processing Systems. 9.\" 10.\" Redistribution and use in source and binary forms, with or without 11.\" modification, are permitted provided that the following conditions 12.\" are met: 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in the 17.\" documentation and/or other materials provided with the distribution. 18.\" 3. 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.\" from: @(#)atexit.3 8.1 (Berkeley) 6/4/93 35.\" 36.Dd June 4, 1993 37.Dt ATEXIT 3 38.Os 39.Sh NAME 40.Nm atexit 41.Nd register a function to be called on exit 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In stdlib.h 46.Ft int 47.Fn atexit "void (*function)(void)" 48.Sh DESCRIPTION 49The 50.Fn atexit 51function 52registers the given 53.Ar function 54to be called at program exit, whether via 55.Xr exit 3 56or via return from the program's 57.Em main . 58Functions so registered are called in reverse order; 59no arguments are passed. 60At least 32 functions can always be registered, 61and more are allowed as long as sufficient memory can be allocated. 62.Sh RETURN VALUES 63.Rv -std atexit 64.Sh ERRORS 65.Bl -tag -width Er 66.It Bq Er ENOMEM 67No memory was available to add the function to the list. 68The existing list of functions is unmodified. 69.El 70.Sh SEE ALSO 71.Xr at_quick_exit 3 , 72.Xr exit 3 , 73.Xr quick_exit 3 74.Sh STANDARDS 75The 76.Fn atexit 77function 78conforms to 79.St -ansiC . 80