exit(2)                                                   exit(2)



     NAME
          exit, _exit - terminate process

     SYNOPSIS
          void exit(status)
          int status;

          void _exit(status)
          int status;

     DESCRIPTION
          exit terminates the calling process with the following
          consequences:

               All of the file descriptors open in the calling process
               are closed.

               If the parent process of the calling process is execut-
               ing a wait(2), it is notified of the termination of the
               calling process and the low-order 8 bits (bits 0377) of
               status are made available to it (see wait(2)).  A
               SIGCHLD signal is sent to the parent process of the
               calling process.

               If the parent process of the calling process is not ex-
               ecuting a wait, the calling process is transformed into
               a zombie process, and the exit status is saved for re-
               turn to the parent should the parent subsequently exe-
               cute a wait(2).  A ``zombie process'' is a process that
               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 times.

               The parent process ID of all existing child processes
               and zombie processes of the calling process is set to
               1.  This means the initialization process (see in-
               tro(2)) inherits each of these processes.

               Each attached shared-memory segment is detached, and
               the value of shm_nattach in the data structure associ-
               ated with its shared memory identifier is decremented
               by 1.

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

               If the process has a process, text, or data lock, an
               unlock is performed (see plock(2)).




     April, 1990                                                     1

     exit(2)                                                   exit(2)



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

               If the process ID, tty group ID, and process group ID
               of the calling process are equal, the SIGHUP signal is
               sent to each process that has a process group ID equal
               to that of the calling process.

               All open file descriptors and directory streams of the
               calling process are closed.  If the process is a con-
               trolling process, a SIGHUP signal is sent to each pro-
               cess in the foreground process group of the controlling
               terminal belonging to the calling process. The control-
               ling terminal associated with the session is disassoci-
               ated from the session.

               If the termination of the calling process causes a pro-
               cess group to be orphaned and if any member of this
               process group is stopped, a SIGHUP, followed by a
               SIGCONT signal is sent to each process in the process
               group.

          The C function exit may cause cleanup actions before the
          process exits.  The function _exit circumvents all cleanup.

     SEE ALSO
          acct(2), fork(2), intro(2), plock(2), semop(2), wait(2),
          signal(3).

     WARNINGS
          See the warning section in signal(3).























     2                                                     April, 1990