Util(3)

NAME
Coro::Util - various utility functions.

SYNOPSIS
 use Coro::Util;

DESCRIPTION
This module implements various utility functions, mostly replacing perl functions by non-blocking counterparts.

Many of these functions exist for the sole purpose of emulating existing interfaces, no matter how bad or limited they are (e.g. no IPv6 support).

This module is an AnyEvent user. Refer to the AnyEvent documentation to see how to integrate it into your own programs.

$ipn = Coro::Util::inet_aton $hostname || $ip
    Works almost exactly like its "Socket::inet_aton" counterpart, except that it does not block other coroutines.

    Does not handle multihomed hosts or IPv6 - consider using "AnyEvent::Socket::resolve_sockaddr" with the Coro rouse functions instead.

gethostbyname, gethostbyaddr
    Work similarly to their Perl counterparts, but do not block. Uses "AnyEvent::Util::inet_aton" internally.

    Does not handle multihomed hosts or IPv6 - consider using "AnyEvent::Socket::resolve_sockaddr" or "AnyEvent::DNS::reverse_lookup" with the Coro rouse functions instead.

@result = Coro::Util::fork_eval { ... }, @args
    Executes the given code block or code reference with the given arguments in a separate process, returning the results. The return values must be serialisable with Coro::Storable. It may, of course, block.

    Note that using event handling in the sub is not usually a good idea as you will inherit a mixed set of watchers from the parent.

    Exceptions will be correctly forwarded to the caller.

    This function is useful for pushing cpu-intensive computations into a different process, for example to take advantage of multiple CPU's. Its also useful if you want to simply run some blocking functions (such as "system()") and do not care about the overhead enough to code your own pid watcher etc.

    This function might keep a pool of processes in some future version, as fork can be rather slow in large processes.

    You should also look at "AnyEvent::Util::fork_eval", which is newer and more compatible to totally broken Perl implementations such as the one from ActiveState.

    Example: execute some external program (convert image to rgba raw form) and add a long computation (extract the alpha channel) in a separate process, making sure that never more then $NUMCPUS processes are being run.

       my $cpulock = new Coro::Semaphore $NUMCPUS;

       sub do_it {
          my ($path) = @_;

          my $guard = $cpulock->guard;

          Coro::Util::fork_eval {
             open my $fh, "convert -depth 8 \Q$path\E rgba:"
                or die "$path: $!";

             local $/;
             # make my eyes hurt
             pack "C*", unpack "(xxxC)*", <$fh>
          }
       }

       my $alphachannel = do_it "/tmp/img.png";

AUTHOR/SUPPORT/CONTACT
   Marc A. Lehmann <schmorp@schmorp.de>
   http://software.schmorp.de/pkg/Coro.html