NAME
    Coro - create and manage coroutines

SYNOPSIS
     use Coro;

     $new = new Coro sub {
        print "in coroutine, switching back\n";
        $Coro::main->resume;
        print "in coroutine again, switching back\n";
        $Coro::main->resume;
     };

     print "in main, switching to coroutine\n";
     $new->resume;
     print "back in main, switch to coroutine again\n";
     $new->resume;
     print "back in main\n";

DESCRIPTION
    This module implements coroutines. Coroutines, similar to continuations,
    allow you to run more than one "thread of execution" in parallel. Unlike
    threads this, only voluntary switching is used so locking problems are
    greatly reduced.

    Although this is the "main" module of the Coro family it provides only
    low-level functionality. See the Coro::Process manpage and related
    modules for a more useful process abstraction including scheduling.

    $main
        This coroutine represents the main program.

    $current
        The current coroutine (the last coroutine switched to). The initial
        value is "$main" (of course).

    $error, $error_msg, $error_coro
        This coroutine will be called on fatal errors. "$error_msg" and
        "$error_coro" return the error message and the error-causing
        coroutine, respectively.

    $coro = new $coderef [, @args]
        Create a new coroutine and return it. The first "resume" call to
        this coroutine will start execution at the given coderef. If it
        returns it should return a coroutine to switch to. If, after
        returning, the coroutine is "resume"d again it starts execution
        again at the givne coderef.

    $coro->resume
        Resume execution at the given coroutine.

BUGS
    This module has not yet been extensively tested.

SEE ALSO
    the Coro::Process manpage, the Coro::Signal manpage.

AUTHOR
     Marc Lehmann <pcg@goof.com>
     http://www.goof.com/pcg/marc/