NAME
exit, _Exit
— perform normal program
termination
LIBRARY
library “libc”
SYNOPSIS
#include
<stdlib.h>
void
exit(int
status);
void
_Exit(int
status);
DESCRIPTION
Theexit()
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), abort2(2), wait(2), at_quick_exit(3), atexit(3), intro(3), quick_exit(3), sysexits(3), tmpfile(3)
STANDARDS
The exit() and
_Exit() functions conform to
ISO/IEC 9899:1999
(“ISO C99”).