xref: /netbsd-src/lib/libc/stdlib/exit.3 (revision 7356612ea6e72b36ccbb310b1d6200a43fcca531)

.\" $NetBSD: exit.3,v 1.17 2019/09/01 19:37:21 sevan Exp $
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.\"     from: @(#)exit.3	8.1 (Berkeley) 6/4/93
.\"
.Dd September 1, 2019
.Dt EXIT 3
.Os
.Sh NAME
.Nm exit
.Nd perform normal program termination
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In stdlib.h
.Ft void
.Fn exit "int status"
.Sh DESCRIPTION
.Fn exit
terminates a process.
The
.Fa status
values
.Dv EXIT_SUCCESS
and
.Dv EXIT_FAILURE
can be used to indicate successful and unsuccessful
termination, respectively.
.Pp
Before termination it 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
Following this,
.Fn exit
calls
.Xr _exit 2 .
.Sh RESTRICTIONS
Standard C guarantees only that the values zero,
.Dv EXIT_SUCCESS ,
and
.Dv EXIT_FAILURE
produce meaningful results.
POSIX extends this to guarantee that the
least significant 8 bits of
.Fa status
are preserved and returned to the parent via
.Xr wait 2 .
Values outside the supported range 0-255 are bitwise-truncated; therefore,
negative values should not be used.
.Sh RETURN VALUES
The
.Fn exit
function
never returns.
.Sh SEE ALSO
.Xr _exit 2 ,
.Xr at_quick_exit 3 ,
.Xr atexit 3 ,
.Xr intro 3 ,
.Xr quick_exit 3 ,
.Xr tmpfile 3
.Sh STANDARDS
The
.Fn exit
function
conforms to
.St -ansiC .
.Sh HISTORY
The
.Fn exit
function appeared in
.At v1 .