freebsd-dev/lib/libc/stdlib/exit.3
Sergio Carlavilla Delgado bbf6efd7b7 exit(3): Add HISTORY section
PR:		240259
Submitted by:	Gordon Bergling
Obtained from:	OpenBSD
Differential Revision:	https://reviews.freebsd.org/D24146
2020-04-10 09:27:18 +00:00

139 lines
3.7 KiB
Groff

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.\" @(#)exit.3 8.1 (Berkeley) 6/4/93
.\" $FreeBSD$
.\"
.Dd March 22, 2020
.Dt EXIT 3
.Os
.Sh NAME
.Nm exit , _Exit
.Nd perform normal program termination
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In stdlib.h
.Ft void
.Fn exit "int status"
.Ft void
.Fn _Exit "int status"
.Sh DESCRIPTION
The
.Fn exit
and
.Fn _Exit
functions terminate a process.
.Pp
Before termination,
.Fn exit
performs the following functions in the order listed:
.Bl -enum -offset indent
.It
Call the functions registered with the
.Xr atexit 3
function, in the reverse order of their registration.
.It
Flush all open output streams.
.It
Close all open streams.
.It
Unlink all files created with the
.Xr tmpfile 3
function.
.El
.Pp
The
.Fn _Exit
function terminates without calling the functions registered with the
.Xr atexit 3
function, and may or may not perform the other actions listed.
Both functions make the low-order eight bits of the
.Fa status
argument available to a parent process which has called a
.Xr wait 2 Ns -family
function.
.Pp
The C Standard
.Pq St -isoC-99
defines the values
.Li 0 ,
.Dv EXIT_SUCCESS ,
and
.Dv EXIT_FAILURE
as possible values of
.Fa status .
Cooperating processes may use other values;
in a program which might be called by a mail transfer agent, the
values described in
.Xr sysexits 3
may be used to provide more information to the parent process.
.Pp
Note that
.Fn exit
does nothing to prevent bottomless recursion should a function registered
using
.Xr atexit 3
itself call
.Fn exit .
Such functions must call
.Fn _Exit
instead (although this has other effects as well which may not be desired).
.Sh RETURN VALUES
The
.Fn exit
and
.Fn _Exit
functions
never return.
.Sh SEE ALSO
.Xr _exit 2 ,
.Xr abort2 2 ,
.Xr wait 2 ,
.Xr at_quick_exit 3 ,
.Xr atexit 3 ,
.Xr intro 3 ,
.Xr quick_exit 3 ,
.Xr sysexits 3 ,
.Xr tmpfile 3
.Sh STANDARDS
The
.Fn exit
and
.Fn _Exit
functions conform to
.St -isoC-99 .
.Sh HISTORY
The
.Fn exit
function appeared in
.At v1 .