Re: static linked lua with loaded modules

[Geoff Leyland <geoff_leyland@...>]

On 6/12/2007, at 8:38 AM, Stefan Sandberg wrote:

> Right, sometimes it works, sometimes it doesn't, but it -should-  
> imo not work, it's incorrect sortof..

Using two different Luas definitely seems incorrect to me.  I'd feel  
pretty bad if I encouraged anybody to do that because it worked by  
luck in one situation for me.  As I said, I now have ONE Lua, and  
it's soooo much better :-)!

> Did you link stuff to symbols exported from your exe? A lot of  
> people on #lua have asked for that lately, so it would be cool for  
> reference if you could spit out how to do that.

Ummm, the trouble is, I don't know what the trick was.  It seemed  
like it wasn't working, and then I thought I changed nothing, and  
then it seemed to be working.  Also, I don't quite remember, and  
digging around in svn hasn't come up with the answer yet.

But anyway, on Visual C++.net 2003 standard edition, with the  
compiler "upgraded" to the free optimizing one they made available on  
the web about, what, four years ago (so pretty old tools).

I think all I needed to do was make sure that you define  
LUA_BUILD_AS_DLL when you're compiling Lua, and it'll set itself up  
to export the symbols (either from a DLL, or from an exe).  However,  
it might be that to get this to work, I had to include the Lua source  
files in the build of the executable, not build Lua into a static  
library, and then link that it.  I have a vague memory of there being  
some kind of problem with that - but svn doesn't teach me anything.

Sorry that's not very useful.  If anyone's really interested, I'll  
have another dig around and see if I can make that work again.

cheers,
Geoff

> Geoff Leyland wrote:
> > On 6/12/2007, at 7:30 AM, John Dunn wrote:
> >
> > > Is it possible to have my app statically link to lua but also  
> > > allow for
> > > DLL based packages to work correctly? I'd like to add support for
> > > sockets in my library using the luasockets package. I've built the
> > > sockets library so it links to a static version of the lua  
> > > library and
> > > it appears to work.I know that by having the app and package  
> > > statically
> > > link they each end up with their own copy of lua - Is this a  
> > > really bad
> > > thing?
> >
> > I used to statically link Lua into one of my apps on windows.  At  
> > first I statically linked all the libraries (lfs, luazip) in too  
> > into one executable.  That worked pretty well, and there was only  
> > one file to "install".
> > Then I statically linked Lua, exported all the Lua symbols from  
> > the app, and dynamically linked lfs and luazip to that.  I used  
> > the multi-threaded DLL run-time and that worked fine.
> > Now I do dynamically link Lua, and that works too.
> >
> > > I have seen luasockets crash a few times - could the multiple  
> > > copies of
> > > lualib cause this sort of thing? In general, is statically  
> > > linking a bad
> > > idea when using .dll based packages?
> >
> > I accidentally used a luazip from a lua.dll, but the luazip was  
> > linked to a lua5.1.dll - and it managed to find one of those on  
> > the path.  It actually worked, but I really don't think it's a  
> > good idea.  (especially when things mysteriously didn't work on  
> > machines where luazip couldn't find a lua5.1.dll).
> >
> > cheers,
> > Geoff