NAME
exit
, _Exit
— perform normal program
termination
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include
<stdlib.h>
void
exit
(int
status);
void
_Exit
(int
status);
DESCRIPTION
The
exit
()
and _Exit
() functions terminate a process.
Before termination,
exit
()
performs the following functions in the order listed:
- Call the functions registered with the atexit(3) function, in the reverse order of their registration.
- Flush all open output streams.
- Close all open streams.
- Unlink all files created with the tmpfile(3) function.
The
_Exit
()
function terminates without calling the functions registered with the
atexit(3)
function, and may or may not perform the other actions listed. Both
functions make the low-order eight bits of the status
argument available to a parent process which has called a
wait(2)-family
function.
The C Standard (ISO/IEC 9899:1999
(“ISO C99”)) defines the values
0
, EXIT_SUCCESS
, and
EXIT_FAILURE
as possible values of
status. Cooperating processes may use other values; in
a program which might be called by a mail transfer agent, the values
described in sysexits(3) may be used to provide more information to the parent
process.
Note that
exit
() does
nothing to prevent bottomless recursion should a function registered using
atexit(3)
itself call exit
(). Such functions must call
_Exit
() instead (although this has other effects as
well which may not be desired).
RETURN VALUES
The exit
() and
_Exit
() functions never return.
SEE ALSO
_exit(2), wait(2), atexit(3), intro(3), sysexits(3), tmpfile(3)
STANDARDS
The exit
() and
_Exit
() functions conform to
ISO/IEC 9899:1999
(“ISO C99”).