NAME

    Child - Object oriented simple interface to fork()

DESCRIPTION

    Fork is too low level, and difficult to manage. Often people forget to
    exit at the end, reap their children, and check exit status. The
    problem is the low level functions provided to do these things. Throw
    in pipes for IPC and you just have a pile of things nobody wants to
    think about.

    Child is an Object Oriented interface to fork. It provides a clean way
    to start a child process, and manage it afterwords. It provides methods
    for running, waiting, killing, checking, and even communicating with a
    child process.

    NOTE: kill() is unpredictable on windows, strawberry perl sends the
    kill signal to the parent as well as the child.

SYNOPSIS

 BASIC

        use Child;
    
        my $child = Child->new(sub {
            my ( $parent ) = @_;
            ....
            # exit() is called for you at the end.
        });
        my $proc = $child->start;
    
        # Kill the child if it is not done
        $proc->is_complete || $proc->kill(9);
    
        $proc->wait; #blocking

 IPC

        # Build with IPC
        my $child2 = Child->new(sub {
            my $self = shift;
            $self->say("message1");
            $self->say("message2");
            my $reply = $self->read(1);
        }, pipe => 1 );
        my $proc2 = $child2->start;
    
        # Read (blocking)
        my $message1 = $proc2->read();
        my $message2 = $proc2->read();
    
        $proc2->say("reply");

 SHORTCUT

    Child can export the child() shortcut function when requested. This
    function creates and starts the child process in one action.

        use Child qw/child/;
    
        my $proc = child {
            my $parent = shift;
            ...
        };

    You can also request IPC:

        use Child qw/child/;
    
        my $child = child {
            my $parent = shift;
            ...
        } pipe => 1;

DETAILS

    First you define a child, you do this by constructing a Child object.
    Defining a child does not start a new process, it is just the way to
    define what the new process will look like. Once you have defined the
    child you can start the process by calling $child->start(). One child
    object can start as many processes as you like.

    When you start a child an Child::Link::Proc object is returned. This
    object provides multiple useful methods for interacting with your
    process. Within the process itself an Child::Link::Parent is created
    and passed as the only parameter to the function used to define the
    child. The parent object is how the child interacts with its parent.

PROCESS MANAGEMENT METHODS

    @procs = Child->all_procs()

      Get a list of all the processes that have been started. This list is
      cleared in processes when they are started; that is a child will not
      list its siblings.

    @pids = Child->all_proc_pids()

      Get a list of all the pids of processes that have been started.

    Child->wait_all()

      Call wait() on all processes.

EXPORTS

    $proc = child( sub { ... } )

    $proc = child { ... }

    $proc = child( sub { ... }, $plugin, @data )

    $proc = child { ... } $plugin => @data

      Create and start a process in one action.

CONSTRUCTOR

    $child = Child->new( sub { ... } )

    $child = Child->new( sub { ... }, $plugin, @plugin_data )

      Create a new Child object. Does not start the child.

OBJECT METHODS

    $proc = $child->start()

      Start the child process.

SEE ALSO

    Child::Link::Proc

      The proc object that is returned by $child->start()

    Child::Link::Parent

      The parent object that is provided as the argument to the function
      used to define the child.

    Child::Link::IPC

      The base class for IPC plugin link objects. This provides the IPC
      methods.

HISTORY

    Most of this was part of Parallel::Runner intended for use in the
    Fennec project. Fennec is being broken into multiple parts, this is one
    such part.

FENNEC PROJECT

    This module is part of the Fennec project. See Fennec for more details.
    Fennec is a project to develop an extendable and powerful testing
    framework. Together the tools that make up the Fennec framework provide
    a potent testing environment.

    The tools provided by Fennec are also useful on their own. Sometimes a
    tool created for Fennec is useful outside the greater framework. Such
    tools are turned into their own projects. This is one such project.

    Fennec - The core framework

      The primary Fennec project that ties them all together.

AUTHORS

    Chad Granum [email protected]

COPYRIGHT

    Copyright (C) 2010 Chad Granum

    Child is free software; Standard perl licence.

    Child is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE. See the license for more details.