_EXIT(2)                      System Calls Manual                     _EXIT(2)


     _exit, _Exit - terminate the calling process


     #include <unistd.h>

     _exit(int status);

     #include <stdlib.h>

     _Exit(int status);


     The _exit() and _Exit() functions terminate a process with the following

     o   All threads in the process are terminated.

     o   All open file descriptors 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.

     o   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 status is set as defined by
         wait(2).  (Note that typically only the lower 8 bits of status are
         passed on to the parent, thus negative values have less meaning.)

     o   The parent process ID of all of the calling process's existing child
         processes are set to 1; the initialization process (see the
         DEFINITIONS section of intro(2)) inherits each of these processes.

     o   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 and SIGCONT
         signals are sent to all members of the newly orphaned process group.

     o   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

     Most C programs call the library routine exit(3), which flushes buffers,
     closes streams, unlinks temporary files, etc., and then calls _exit().


     _exit() and _Exit() can never return.


     fork(2), intro(2), sigaction(2), wait(2), exit(3), sysexits(3)


     The _exit() function conform to IEEE Std 1003.1-2008 ("POSIX.1").  The
     _Exit() function conforms to ISO/IEC 9899:1999 ("ISO C99").


     An exit() system call first appeared in Version 1 AT&T UNIX.  It accepts
     the status argument since Version 2 AT&T UNIX.  An _exit() variant first
     appeared in Version 7 AT&T UNIX.  The _Exit() function appeared in
     OpenBSD 3.6.

OpenBSD 6.2                   September 10, 2015                   OpenBSD 6.2

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