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.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
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.\"
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" manual provided the copyright notice and this permission notice are
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.\" preserved on all copies.
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.\"
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.\" Permission is granted to copy and distribute modified versions of this
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.\" manual under the conditions for verbatim copying, provided that the
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.\" entire resulting derived work is distributed under the terms of a
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.\" permission notice identical to this one.
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.\"
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
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.\" responsibility for errors or omissions, or for damages resulting from
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.\" the use of the information contained herein. The author(s) may not
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.\" have taken the same level of care in the production of this manual,
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.\" which is licensed free of charge, as they might when working
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.\" professionally.
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.\"
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.\" Formatted or processed versions of this manual, if unaccompanied by
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.\" the source, must acknowledge the copyright and authors of this work.
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.\"
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.\" References consulted:
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.\" Linux libc source code
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.\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
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.\" 386BSD man pages
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.\" Modified 1993-03-29, David Metcalfe
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.\" Modified 1993-07-24, Rik Faith (faith@cs.unc.edu)
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.\" Modified 2003-10-25, Walter Harms
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.\"
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.TH ATEXIT 3 2003-11-01 "" "Linux Programmer's Manual"
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.SH NAME
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atexit \- register a function to be called at normal process termination
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.SH SYNOPSIS
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.nf
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.B #include <stdlib.h>
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.sp
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.BI "int atexit(void (*" function )(void));
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.fi
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.SH DESCRIPTION
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The \fBatexit()\fP function registers the given \fIfunction\fP to be
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called at normal process termination, either via
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.BR exit (3)
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or via return from the program's \fBmain\fP().
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Functions so registered are called in
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the reverse order of their registration; no arguments are passed.
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.LP
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POSIX.1 requires that an implementation allow at least ATEXIT_MAX (32)
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process termination functions to be registered.
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The actual limit supported by an implementation can be obtained using
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.BR sysconf (3).
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.LP
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Upon a successful call to one of the exec functions,
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the registrations of all process termination functions are removed.
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.SH "RETURN VALUE"
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The \fBatexit()\fP function returns the value 0 if successful; otherwise
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it returns a non-zero value.
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.SH EXAMPLE
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.nf
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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void bye(void) {
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printf("That was all, folks\en");
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}
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int main(){
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long a;
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int i;
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a = sysconf(_SC_ATEXIT_MAX);
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printf("ATEXIT_MAX = %ld\en", a);
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i = atexit(bye);
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if (i != 0) {
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fprintf(stderr, "cannot set exit function\en");
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return EXIT_FAILURE;
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}
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return EXIT_SUCCESS;
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}
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.fi
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.SH "CONFORMING TO"
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SVID 3, BSD 4.3, ISO 9899, POSIX 1003.1-2001
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.SH "SEE ALSO"
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.BR _exit (3),
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.BR exit (3),
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.BR on_exit (3)
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