NAME
   Parallel::Prefork - A simple prefork server framework

SYNOPSIS
     use Parallel::Prefork;

     my $pm = Parallel::Prefork->new({
       max_workers  => 10,
       trap_signals => {
         TERM => 'TERM',
         HUP  => 'TERM',
         USR1 => undef,
       }
     });

     while ($pm->signal_received ne 'TERM') {
       load_config();
       $pm->start and next;

       ... do some work within the child process ...

       $pm->finish;
     }

     $pm->wait_all_children();

DESCRIPTION
   "Parallel::Prefork" is much like "Parallel::ForkManager", but supports
   graceful shutdown and run-time reconfiguration.

METHODS
 new
   instantiation. Takes a hashref as an argument. Recognized attributes are
   as follows.

  max_workers
   number of worker processes (default: 10)

  spawn_interval
   interval in seconds between spawning child processes unless a child
   process exits abnormally (default: 0)

  err_respawn_interval
   number of seconds to deter spawning of child processes after a worker
   exits abnormally (default: 1)

  trap_signals
   hashref of signals to be trapped. Manager process will trap the signals
   listed in the keys of the hash, and send the signal specified in the
   associated value (if any) to all worker processes. If the associated
   value is a scalar then it is treated as the name of the signal to be
   sent immediately to all the worker processes. If the value is an
   arrayref the first value is treated the name of the signal and the
   second value is treated as the interval (in seconds) between sending the
   signal to each worker process.

  on_child_reap
   coderef that is called when a child is reaped. Receives the instance to
   the current Paralle::Prefork, the child's pid, and its exit status.

 start
   The main routine. Returns undef in child processes. Returns a true value
   within manager process upon receiving a signal specified in the
   "trap_signals" hashref.

 finish
   Child processes should call this function for termination. Takes exit
   code as an optional argument. Only usable from child processes.

 signal_all_children
   Sends signal to all worker processes. Only usable from manager process.

 wait_all_children
   Blocks until all worker processes exit. Only usable from manager
   process.

AUTHOR
   Kazuho Oku

LICENSE
   This program is free software; you can redistribute it and/or modify it
   under the same terms as Perl itself.

   See http://www.perl.com/perl/misc/Artistic.html