RFE: Expose fd to easily attach to another event loop

[lestrrat]

I basically want to plug zeromq into another event loop, so that the I/O watcher of that event loop can handle readable file descriptors.

I'm actually doing this for the perl binding. The end effect I want is something like:

 my $w;
 $w = AnyEvent->io( fh => $socket->fd, poll => "r", callback => sub {
      my $msg = $socket->recv( ZMQ_NOBLOCK );
      if ($msg) {
           undef $w;
           process_message( $msg );
      }
 } );

which would be doable if the socket constructs has some sort of accessor to the underlying file descriptor. (And since I'm using the C wrapper, an equivalent C function to go along with it)

Would something like this be feasible in the next coming version?

[sustrik]

The functionality is already merged in the trunk (to be released as 0MQ/2.1). Use ZMQ_FD socket option to get the file descriptor. Note that it signaling POLLIN means just "something happened with the socket". You still have to check another socket option (ZMQ_EVENTS) to find out whether the socket became readble/writable.