-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | Start background daemons by double-forking
--   
--   This package has been deprecated in favour of
--   <a>http://hackage.haskell.org/package/daemons</a>.
--   
--   Start background daemons by double-forking.
--   
--   See <a>System.Posix.Daemon</a> for documentation.
@package daemonize-doublefork
@version 0.1.1


-- | This module provides <a>startDaemon</a> and <a>stopDaemon</a> to
--   facilitate the creation of daemon programs.
--   
--   The problem is as follows: the user starts a program in their
--   terminal, but he wants the program to relinquish control of the
--   terminal immediately, and furthermore, the program (or part of it)
--   should keep running even after said terminal is closed. Examples of
--   programs that behave like this are <tt>nginx</tt> and <tt>emacs
--   --daemon</tt>.
--   
--   The correct solution is to double-fork a process. This ensures that
--   the child process is completed separated from the terminal it was
--   started on.
module System.Posix.Daemon

-- | Double-fork to create a well behaved daemon. If PIDFILE is given,
--   check/set pidfile; if we cannot obtain a lock on the file, another
--   process is already using it, so fail. The program is started with
--   <tt>SIGHUP</tt> masked; HANDLER is invoked on <tt>SIGHUP</tt>.
--   
--   See: <a>http://www.enderunix.org/docs/eng/daemon.php</a>
--   
--   Note: All unnecessary fds should be close before calling this.
--   
--   HANDLER is meant to allow the daemon to shutdown cleanly. It could
--   simply be:
--   
--   <pre>
--   handler = return ()
--   </pre>
--   
--   or something more elaborate like the following, which allows one to
--   perform some actions before re-raising the signal and killing the
--   daemon:
--   
--   <pre>
--   handler = do
--     putStrLn <a>Stopping daemon...</a>
--     raiseSignal sigTERM
--   </pre>
startDaemon :: FilePath -> IO () -> IO () -> IO ()

-- | Stop the daemon identified by PIDFILE by sending it <tt>SIGHUP</tt>.
--   If the process was daemonized with <a>startDaemon</a>, the handler
--   specified there will be invoked first. Return the pid of the process
--   that was killed; if PIDFILE does not exist, return <a>Nothing</a>.
stopDaemon :: FilePath -> IO (Maybe ProcessID)

-- | Make the current process belong to USER and GROUP.
becomeGroupUser :: String -> String -> IO ()