exit(2) 							   System Calls 							   exit(2)

NAME

       exit, _Exit, _exit - terminate process

SYNOPSIS

       #include <stdlib.h>

       void exit(int status);

       void _Exit(int status);

       #include <unistd.h>

       void _exit(int status);

DESCRIPTION

       The  exit() function first calls all functions registered by atexit(3C), in the reverse order of their registration, except that a function
       is called after any previously registered functions that had already been called at the time it was registered. Each function is called	as
       many  times as it was registered. If, during the call to any such function, a call to the longjmp(3C) function is made that would terminate
       the call to the registered function, the behavior is undefined.

       If a function registered by a call to atexit(3C) fails to return, the remaining registered functions are not called and	the  rest  of  the
       exit() processing is not completed. If exit() is called more than once, the effects are undefined.

       The  exit()  function then flushes all open streams with unwritten buffered data, closes all open streams, and removes all files created by
       tmpfile(3C).

       The _Exit() and _exit() functions are functionally equivalent. They do not call functions registered with atexit(), do not call any  regis-
       tered signal handlers, and do not flush open streams.

       The _exit(), _Exit(), and exit() functions terminate the calling process with the following consequences:

	   o	  All  of  the	file  descriptors, directory streams, conversion descriptors and message catalogue descriptors open in the calling
		  process are closed.

	   o	  If the parent process of the calling process is executing a wait(3C), wait3(3C), waitid(2), or waitpid(3C), and has neither  set
		  its  SA_NOCLDWAIT  flag  nor set SIGCHLD to SIG_IGN, it is notified of the calling process's termination and the low-order eight
		  bits (that is, bits 0377) of status are made available to it.  If the parent is not waiting, the child's  status  will  be  made
		  available to it when the parent subsequently executes wait(), wait3(), waitid(), or waitpid().

	   o	  If  the  parent  process  of the calling process is not executing a wait(), wait3(), waitid(), or waitpid(), and has not set its
		  SA_NOCLDWAIT flag, or set SIGCHLD to SIG_IGN, the calling process is transformed into a zombie process. A zombie process  is	an
		  inactive  process and it will be deleted at some later time when its parent process executes wait(), wait3(), waitid(), or wait-
		  pid(). A zombie process only occupies a slot in the process table; it has no other space allocated  either  in  user	or  kernel
		  space.  The  process table slot that it occupies is partially overlaid with time accounting information (see <sys/proc.h>) to be
		  used by the times(2) function.

	   o	  Termination of a process does not directly terminate its children. The sending of a SIGHUP signal as described below	indirectly
		  terminates children in some circumstances.

	   o	  A SIGCHLD will be sent to the parent process.

	   o	  The  parent process ID of all of the calling process's existing child processes and zombie processes is set to 1. That is, these
		  processes are inherited by the initialization process (see Intro(2)).

	   o	  Each mapped memory object is unmapped.

	   o	  Each attached shared-memory segment is detached and the value of shm_nattch (see shmget(2)) in  the  data  structure	associated
		  with its shared memory ID is decremented by 1.

	   o	  For each semaphore for which the calling process has set a semadj value (see semop(2)), that value is added to the semval of the
		  specified semaphore.

	   o	  If the process is a controlling process, the SIGHUP signal will be sent to each process in the foreground process group  of  the
		  controlling terminal belonging to the calling process.

	   o	  If the process is a controlling process, the controlling terminal associated with the session is disassociated from the session,
		  allowing it to be acquired by a new controlling process.

	   o	  If the exit of the process causes a process group to become orphaned, and if any member of the newly-orphaned process  group	is
		  stopped, then a SIGHUP signal followed by a SIGCONT signal will be sent to each process in the newly-orphaned process group.

	   o	  If  the  parent process has set its SA_NOCLDWAIT flag, or set SIGCHLD to SIG_IGN, the status will be discarded, and the lifetime
		  of the calling process will end immediately.

	   o	  If the process has process, text or data locks, an UNLOCK is performed (see plock(3C) and memcntl(2)).

	   o	  All open named semaphores in the process are closed as if by appropriate calls to sem_close(3C). All open message queues in  the
		  process are closed as if by appropriate calls to mq_close(3C). Any outstanding asynchronous I/O operations may be cancelled.

	   o	  An accounting record is written on the accounting file if the system's accounting routine is enabled (see acct(2)).

	   o	  An  extended	accounting  record  is written to the extended process accounting file if the system's extended process accounting
		  facility is enabled (see acctadm(1M)).

	   o	  If the current process is the last process within its task and if the system's extended task accounting facility is enabled (see
		  acctadm(1M)), an extended accounting record is written to the extended task accounting file.

RETURN VALUES

       These functions do not return.

ERRORS

       No errors are defined.

USAGE

       Normally applications should use exit() rather than _exit().

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Committed 		   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |See below.		   |
       +-----------------------------+-----------------------------+
       |Standard		     |See standards(5). 	   |
       +-----------------------------+-----------------------------+

       The _exit() and _Exit() functions are Async-Signal-Safe.

SEE ALSO

       acctadm(1M),  Intro(2),	acct(2),  close(2),  memcntl(2),  semop(2),  shmget(2), sigaction(2), times(2), waitid(2), atexit(3C), fclose(3C),
       mq_close(3C), plock(3C), signal.h(3HEAD), tmpfile(3C), wait(3C), wait3(3C), waitpid(3C), attributes(5), standards(5)

SunOS 5.11							    5 Feb 2008								   exit(2)