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
          executing 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
          executing a wait, the calling process is transformed
          into a zombie process, and the exit status is saved for
          return to the parent should the parent subsequently
          execute 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
          intro(2)) inherits each of these processes.

          Each attached shared-memory segment is detached, and
          the value of shm_nattach in the data structure
          associated 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)).




January 1992                                                    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
          controlling process, a SIGHUP signal is sent to each
          process in the foreground process group of the
          controlling terminal belonging to the calling process.
          The controlling terminal associated with the session is
          disassociated from the session.

          If the termination of the calling process causes a
          process 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.

WARNINGS
     See the warning section in signal(3).

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























2                                                    January 1992