Hey guys, what library or sources do you recommend for learning how to implement netplay into your Allegro games? Something simple like an artillery game I mean, probably just over LAN. Anything for Windows and Mac?

I used to use ZoidCom, but have since migrated to eNet http://enet.bespin.org/ as it provides a lot more control and doesn't try to do everything for you (that and it can be statically linked unlike ZoidCom).

Never heard of zeromq, may be worth a look.

For something simple as an artillery game he does not need those hi-perf library.

A simple wrapper for sockets can do the trick.

Here is how I use mine, it's C and I can give you the sources and a working client server example.

Anyway, it's just so you get the idea. It's compiling under windows and linux. Compiling under mac should be trivial.

Those sock-it rappers are a lot easier looking, but I can't tell what's plain C or what's custom functions. Would I be able to use a LAN with that? Like I guess one computer would function as the host? I guess I'm kind of unfamiliar with the whole process.

Felix, take a look at the basics in the beejs guide. If it looks too much complicated then go for enet or whatever.

Writing a wrapper like mine is a 3 days works with the help of the beej's guide. Go Felix, go !

Yeah, I know what I typed when I said sock-it rappers
So...beej's guide, eh?*
I'll check it out -- thanks for the encouragement everyone.

_{*I've been to Canada for a few days and never heard anyone say this}

Hmm. I obvioulsy haven't read it all, but I noticed

#include <winsock.h>

I guess I wouldn't be able to use the same code in Mac and Win

Does anyone here have anything to say about boost::asio? I know next to nothing about sockets and networking etc. but that's what I've been experimenting with recently. How does ::asio compare to something like hawknl or enet?

By that, do you mean it is like comparing two network libraries that are designed with different target audiences in mind — and that there is one that most people would prefer to have, but that one is much more expensive? I wonder which one is which!? ...

Part of the reason I started looking at ::asio is that I heard somewhere that it might become part of the standard C++0x library. I don't know if that's true or not, but if is true then I figure that it's worth knowing about.

[edit]
I've just been reading about enet. It sounds pretty good. My understanding is that it is a layer on top of UDP which adds a bunch of useful features such reliable delivery, ordered delivery in multiple channels, and so on; and it is designed to fast (ie. low-latency). So that all sounds pretty good. Enet is probably better than any UDP overlay* that I'm likely to make. (*or whatever such layers are meant to be called... overlay sounds like a good enough term for it.)

But... suppose I'm making a turn-based game in which latency isn't particularly important, and suppose I put a high value on using 'standard' protocols and libraries for support and security reasons (or whatever other reasons). In that case, how does Enet compare to boost::asio::tcp? It seems to me that if the latency advantages of Enet are not important to me, then maybe the boost::asio would be the better choice just because it is the better known 'brand'.

I'm interested to hear more thoughts and comments about this.

The nice thing about a premade library is that you don't have to deal with the mundane boilerplate code, writing the ifdefs for winsock, etc.

3 copy paste. Perhaps 4 or 5 and I do not touch write something else than google search key.
Pastes:
1) Copy #ifdef WIN32
2) Copy Win32headers
3) Copy #else
4) Copy *nix headers
5) Copy #endif keyboard.

Even if you are a lazy guys, that's quicker than downloading and installing a library.

Copy paste from beej guides and you'll have a basic client server.

Hell I didn't ever wrote a line of code !

Well you have idea.

Yeah. Let's embed a 1000000K lines of code instead of 100k lines just before we can't afford to include a #ifdef.

Plus don't dare to say all all your project are already coded to be cross platform. In most way, especially for a game, you'll target win32 computers. As said before, there are only the headers and a few variables to take in account (like 3) and you have your cross platform sock library.

Boost:asio server example (from the docs)

#include <cstdlib>
#include <iostream>
#include <boost/aligned_storage.hpp>
#include <boost/array.hpp>
#include <boost/bind.hpp>
#include <boost/enable_shared_from_this.hpp>
#include <boost/noncopyable.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/asio.hpp>

that's what I call a bunch for doing a simple thing as turn based data. I would use Boost:asio for an html viewer, some kind of webservice, ect. But not for a game.
http://www.boost.org/doc/libs/1_44_0/doc/html/boost_asio/examples.html

I said ENET is overwhelmed because it's more aimed to fast paced network than to turn based.

If I was to choose between ENET and Boost:asio I would go for Enet which is a lot simpler to implement.
http://enet.bespin.org/Tutorial.html

And if you leave the choice to me, I would use a simple wrapper, as simple as possible, around the socket library (and use TCP BTW).