NAME
_exit
—
terminate the calling
process
LIBRARY
library “libc”
SYNOPSIS
#include
<unistd.h>
void
_exit
(int
status);
DESCRIPTION
The_exit
()
system call terminates a process with the following consequences:
- All of the descriptors open in the calling process are closed. This may entail delays, for example, waiting for output to drain; a process in this state may not be killed, as it is already dying.
- If the parent process of the calling process has an outstanding
wait(2) call or catches the
SIGCHLD
signal, it is notified of the calling process's termination and the status is set as defined by wait(2). - The parent process-ID of all of the calling process's existing child processes are set to the process-ID of the calling process's reaper; the reaper (normally the initialization process) inherits each of these processes (see procctl(2), init(8) and the DEFINITIONS section of intro(2)).
- If the termination of the process causes any process group to become
orphaned (usually because the parents of all members of the group have now
exited; see “orphaned process group” in
intro(2)), and if any member of the orphaned group is stopped, the
SIGHUP
signal and theSIGCONT
signal are sent to all members of the newly-orphaned process group. - If the process is a controlling process (see
intro(2)), the
SIGHUP
signal is sent to the foreground process group of the controlling terminal, and all current access to the controlling terminal is revoked.
Most C programs call the library routine
exit(3), which flushes buffers, closes streams, unlinks temporary
files, etc., before calling
_exit
().
RETURN VALUES
The _exit
() system call can never
return.
SEE ALSO
STANDARDS
The _exit
() system call is expected to
conform to IEEE Std 1003.1-1990
(“POSIX.1”).
HISTORY
The _exit
() function appeared in
Version 7 AT&T UNIX.