Re: Problem in Lua for Windows with UDP multicast receive

[Herbert Leuwer <herbert.leuwer@...>]

I would like to come back to this issue. In the meanwhile I have tested the same script
in the following environments. The behavior of the call
	udp:setoption("ip-add-membership", "224.0.0.1")
is as follows:

1. QNX: setoption(...) works and multicast reception as well
2. Lua For Windows: setoption(...) fails
3. Cygwin: setoption(...) works and multicast reception as well

My feeling is that cygwin uses the correct header/library combination.

So my question to the developers for Windows would be to investigate this issue in
their source code environment and hopefuly be able to fix this problem.

Thanks a lot
Herbert

Tim Channon schrieb:
> Herbert Leuwer wrote:
> > I tried to add multicast membership to a datagram socket for IP
> > multicast using udp:setoption(...), but the call allways fails.
> > After some browsing I found a possible cause related to this article of
> > MSDN:
> >
> > http://support.microsoft.com/kb/257460/en
> >
> > Looking into the original luasocket code, I found that luasocket seems
> > to use winsock.h while clibs\socket\core.dll seems to be linked against
> > ws2_32.lib. This would be the non-tolerant header/lib combination named
> > in the article above.
> >
> > The same Lua receive script works fine in a non-Windows environment.
> >
> > Sending of multicast packets works also in Windows.
> >
> > I used the latest Lua for Windows version.
>
> Looks like a long story, is about a change in the specification on
> multicast. Berkeley changed but the older Steve Deering definitions
> stayed in winsock 1 API.
> Try this http://www.sockets.com/ch16.htm#Multicast
>
> Changed luasocket.h to include winsock2.h
>
> Compile fails on multicast Lua code.
>
> Do as the Microsoft doc you cite says, fragment of Luasocket.h follows
> and is linked with ws2_32
>
> /*=========================================================================*\
> * WinSock include files
> \*=========================================================================*/
> #include <winsock2.h> /*TNC changed from winsock.h */
> #include <Ws2tcpip.h> /*TNC added */
>
> typedef int socklen_t;
> typedef SOCKET t_socket;
> typedef t_socket *p_socket;
>
> And compiles fine. I do not know whether this fixes things.
>
> Tim