ee62fb2e1e
Remove a useless note about unlinking temporary files, they are unlinked in tmpfile(3) [1]. Add a note about __cxa_atexit(). Explain exactly what are the FreeBSD implementation differences between exit() and _Exit(). Noted by: markj [1] Reviewed by: emaste, markj Sponsored by: The FreeBSD Foundation MFC after: 3 days Differential revision: https://reviews.freebsd.org/D31425
147 lines
3.9 KiB
Groff
147 lines
3.9 KiB
Groff
.\" Copyright (c) 1990, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" This code is derived from software contributed to Berkeley by
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.\" the American National Standards Committee X3, on Information
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.\" Processing Systems.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)exit.3 8.1 (Berkeley) 6/4/93
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.\" $FreeBSD$
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.\"
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.Dd August 5, 2021
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.Dt EXIT 3
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.Os
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.Sh NAME
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.Nm exit , _Exit
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.Nd perform normal program termination
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In stdlib.h
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.Ft void
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.Fn exit "int status"
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.Ft void
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.Fn _Exit "int status"
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.Sh DESCRIPTION
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The
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.Fn exit
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and
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.Fn _Exit
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functions terminate a process.
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.Pp
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Before termination,
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.Fn exit
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performs the following functions in the order listed:
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.Bl -enum -offset indent
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.It
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Call all functions registered with the
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.Xr __cxa_atexit 3
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function
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(which are typically destructors from the loaded dynamic objects),
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and the functions registered with the
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.Xr atexit 3
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function, in the reverse order of their registration.
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.It
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Flush all open output streams.
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.It
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Close all open streams.
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.El
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.Pp
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The
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.Fn _Exit
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function terminates without calling the functions registered with the
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.Xr atexit 3
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function, and may or may not perform the other actions listed.
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The
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.Fx
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implementation of the
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.Fn _Exit
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function does not call destructors registered with
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.Xr __cxa_atexit 3,
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does not flush buffers, and does not close streams.
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.Pp
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Both functions make the low-order eight bits of the
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.Fa status
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argument available to a parent process which has called a
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.Xr wait 2 Ns -family
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function.
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.Pp
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The C Standard
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.Pq St -isoC-99
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defines the values
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.Li 0 ,
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.Dv EXIT_SUCCESS ,
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and
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.Dv EXIT_FAILURE
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as possible values of
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.Fa status .
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Cooperating processes may use other values;
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in a program which might be called by a mail transfer agent, the
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values described in
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.Xr sysexits 3
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may be used to provide more information to the parent process.
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.Pp
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Note that
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.Fn exit
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does nothing to prevent bottomless recursion should a function registered
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using
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.Xr atexit 3
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itself call
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.Fn exit .
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Such functions must call
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.Fn _Exit
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instead (although this has other effects as well which may not be desired).
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.Sh RETURN VALUES
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The
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.Fn exit
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and
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.Fn _Exit
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functions
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never return.
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.Sh SEE ALSO
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.Xr _exit 2 ,
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.Xr abort2 2 ,
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.Xr wait 2 ,
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.Xr at_quick_exit 3 ,
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.Xr atexit 3 ,
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.Xr intro 3 ,
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.Xr quick_exit 3 ,
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.Xr sysexits 3 ,
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.Xr tmpfile 3
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.Sh STANDARDS
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The
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.Fn exit
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and
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.Fn _Exit
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functions conform to
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.St -isoC-99 .
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.Sh HISTORY
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The
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.Fn exit
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function appeared in
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.At v1 .
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