Re: LuaJIT 2 vs. C modules built for Lua

[Geoff Leyland <geoff_leyland@...>]

On 10/11/2009, at 9:01 PM, Alexander Gladysh wrote:

> Hi, list!
>
> This looks like a silly question, and I feel that it should be
> documented somewhere, but anyway:
>
> Can LJ2 be used with C modules, linked with Lua (on Linux / OS X  
> platforms)?

Yes, it works for me.  The API is the same.

> My intuition says "no". Then I feel that LJ2 should ignore LUA_CPATH
> and have its own environment variable.

I use the exact same modules from the same path for lua and luajit.

> Looks like practice says "yes" — what I've tried worked. But this is
> strange. What am I missing? What are the consequences? What if modules
> are accidentally compiled as 64-bit code?

(I think you mentioned earlier you were on OS X?)

Since snow leopard, upgrading macports and LJ2 I keep tripping over  
32/64 bit issues.  I *think* I've got it fixed now - lua and all my  
modules are built as fat binaries for both 32 and 64 bit.  LJ2 is 32  
bit.  I assume Lua uses the 64 bit half of the binary and LJ2 the 32  
bit half.

The last hiccup I had was that up until a couple of weeks ago,  
macports failed to build lua +universal as a universal binary, and I  
needed to do a "macport selfupdate" to get the fix.  Using "lipo - 
info" to check that you actually got fat binaries is a very good idea.

Cheers,
Geoff