[C++] Lua integration

On the official Lua website you can find a lot of information.

Here is a description how you can build lua with several different compilers

I checked out the links, but they werent really what I was looking for. I'll just ask a specific question. I was trying to follow this tutorial: http://www.gamedev.net/reference/articles/article1932.asp

My problem is that it says that 'lua.h' doesnt exist, and I have no idea why. I have my sourcecode in the right spot and everything. i'm using Dev C++

Quote:

Original post by Terradigits I checked out the links, but they werent really what I was looking for. I'll just ask a specific question. I was trying to follow this tutorial: http://www.gamedev.net/reference/articles/article1932.asp My problem is that it says that 'lua.h' doesnt exist, and I have no idea why. I have my sourcecode in the right spot and everything. i'm using Dev C++

Where is lua.h in your dev-cpp/include folder? If its in a sub-directory like dev-cpp/include/lua/lua.h (like mine) you will need to add this directory to your build path.

If lua is a library you use or will use often, add it to the compilers build path in tools->compilers->directories->(C/C++) includes

If its only used in this project and wont be using often, you can add it just to that project in project->project options->directories->includes

Finally, if you are using lua in C++ you should #include "lua.hpp" and not lua.h.

If you're simply trying to compile the LUA source, then you're in luck since I've just done exactly that.

First add the mingw bin path (came with dev-cpp) to your PATH environment variable. This is done in the control panel under System->Advanced->Environment variables. Under 'system variables' find the one called 'Path' and add a semicolon and the dev-cpp bin path to the end so it looks something like this:
%SystemRoot%\system32[...];C:\Dev-Cpp\bin

Now you can use a lot of wonderful compilation (et al) tools, including make which is what you need here. Press Start->Run and type in 'cmd' [enter]. Then cd to your lua dir, ie. 'cd c:\lua' and write 'make mingw' [enter].

That's it. Happy programming!

Well, I have the lua.h problem fixed, but a new one has arisen. The following code seems to no longer work:

#include <stdio.h>extern "C"{ #include "lua.h"} int main(int argc, char* argv[ ]){   lua_State* luaVM = lua_open(0);    if (NULL == luaVM)   {      printf("Error Initializing lua\n");      return -1;   }    // Do stuff with lua code.       lua_close( luaVM );    return 0;}

it states that lua_open is undeclared.

That's because the article was written for version 4.0.1. I assume you are using at least 5.0 or the newest release 5.1.1. Beyond version 4 lua_open was redefined to not take a stack size argument.

Try:

If you're binding C++ and LUA I highly suggest using luabind:

http://www.rasterbar.com/products/luabind/docs.html

Quote:

Original post by Terradigits Well, I have the lua.h problem fixed, but a new one has arisen. The following code seems to no longer work: *...snip...* it states that lua_open is undeclared.

I had the identical problem awhile back. Lua 5.0 doesn't use lua_open (at least not directly... it should still work, technically, but it doesn't). Check out some documentation on luaL_newstate() on the Lua site. Basically, you can look at this as the "new" lua open. Actually, I find Lua 4.0 to be much easier than 5.* on the C/++ side of things (though that's just my opinion), so you might consider just using 4 for learning purposes. Certainly it'll make that tutorial easier to follow.

Another note: lua.hpp > lua.h for C++. It's basically this:

extern "C"{#include lua.h#include lauxlib.h#include // some other header... not sure which}

which makes it infinitely better for C++, as it includes EVERYTHING you need.

Quote:

Original post by EmrldDrgn Actually, I find Lua 4.0 to be much easier than 5.* on the C/++ side of things (I can't seem to find a simple "DoFile" method in 5.*), so you might consider just using 4 for learning purposes. Certainly it'll make that tutorial easier to follow.

In 5.0:
lua_dofile in lauxlib.h

In 5.1:
luaL_dofile in lauxlib.h

Hope that helps :)

Sorry guys, but I still cant get it working. Neither 4.0 or 5.0 will work. It keeps saying lua_open() is undefined.

Someone did post above suggesting that you don't use lua_open. You haven't told us which version of Lua you're using, either. Lua changes a lot from version to version so it's an important detail.

Well, i've tried both versions. Lua_open() won't work on v4, and the equivalant won't work on v5

Well, I think I have everything worked out now. However, I still get one error during the linking process. Here is my log file:

------ Build started: Project: luatest, Configuration: Debug Win32 ------
Linking...
LINK : fatal error LNK1104: cannot open file 'uuid.lib'
Build log was saved at "file://c:\Documents and Settings\xxx\My Documents\Visual Studio 2005\Projects\luatest\luatest\Debug\BuildLog.htm"
luatest - 1 error(s), 0 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

Quote:

Original post by Zorbfish Quote: Original post by EmrldDrgn Actually, I find Lua 4.0 to be much easier than 5.* on the C/++ side of things (I can't seem to find a simple "DoFile" method in 5.*), so you might consider just using 4 for learning purposes. Certainly it'll make that tutorial easier to follow. In 5.0: lua_dofile in lauxlib.h In 5.1: luaL_dofile in lauxlib.h Hope that helps :)

Hehe... my bad :). Thanks.

Anyway, I don't know what your problem there might be, but I suggest you make sure you're doing the following:
1) #include-ing lua.hpp instead of extern "C"-ing lua.h. Apart from a timesaver, it grabs the laux files you'll need as well.
2) #pragma comment(lib, lua5.1.1.lib), or adding the .lib as a dependancy in project settings.
3) Only have 1 lua version on your include and libs paths at any given time. Otherwise they'll probably fight.

I tried all of those, none of them worked :(. I still get the same error. I'm starting to think i'll never get this working...

I Google-d around for you real quick, and it appears uuid.lib is in the PSDK, which is used for a lot of stuff. Make sure you (re-)install that, found here.
Should be the correct version, no promises.
EDIT: Linkified... forgot the ""'s. Whoops...

[Edited by - EmrldDrgn on February 23, 2007 8:03:37 PM]

Emerald:
http://www.gamedev.net/community/forums/faq.asp

Terradigits:
I do not think uuid.lib is a problem having to do with Lua.

Just as a quick question:
Did you compile the version of the Lua library you are using or did you use a prebuilt binary?

How about trying one of the standard binaries here with the code everyone has suggested and see if that works for you. You want to download the lua5_1_1_Win32_dll8_lib.zip distributable for VC++2k5.