Lua embedding issues

eucharn · 07-02-2005, 08:20 PM

Yay! I'm not a hardened Linux geek yet (but I aim to become

) and I've got some experience with Lua embedding in XP but know I'm stuck! I have a simple question (I think), but first I think I would fill in some information:

Distro:
Mandrake LE2005

GCC (gcc -v):
Reading specs from /usr/lib/gcc/i586-mandrake-linux-gnu/3.4.3/specs
Configured with: ../configure --prefix=/usr --libexecdir=/usr/lib --with-slibdir=/lib --mandir=/usr/share/man --infodir=/usr/share/info --enable-shared --enable-threads=posix --disable-checking --enable-long-long --enable-__cxa_atexit --enable-clocale=gnu --disable-libunwind-exceptions --enable-languages=c,c++,ada,f77,objc,java --host=i586-mandrake-linux-gnu --with-system-zlib
Thread model: posix
gcc version 3.4.3 (Mandrakelinux 10.2 3.4.3-7mdk)

Kdevelop:
Version 3.1.2

Lua:
Version 5.0

The thing is when I just link to liblua.a (-llua) it's ok, but as soon as I try to link liblualib.a (-llualib) into the project I get these errors:

Code:

/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.3/../../../liblualib.so: undefined reference to `log'
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.3/../../../liblualib.so: undefined reference to `sqrt'
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.3/../../../liblualib.so: undefined reference to `dlerror'
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.3/../../../liblualib.so: undefined reference to `dlclose'
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.3/../../../liblualib.so: undefined reference to `fmod'
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.3/../../../liblualib.so: undefined reference to `cos'
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.3/../../../liblualib.so: undefined reference to `sin'
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.3/../../../liblualib.so: undefined reference to `atan2'
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.3/../../../liblualib.so: undefined reference to `dlopen'
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.3/../../../liblualib.so: undefined reference to `pow'
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.3/../../../liblualib.so: undefined reference to `log10'
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.3/../../../liblualib.so: undefined reference to `dlsym'
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.3/../../../liblualib.so: undefined reference to `exp'
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.3/../../../liblualib.so: undefined reference to `tan'
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.3/../../../liblualib.so: undefined reference to `atan'
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.3/../../../liblualib.so: undefined reference to `asin'
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.3/../../../liblualib.so: undefined reference to `acos'

The code I tried to compile:

Code:

#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"

lua_State* luavm;

int main (int argc, char *argv[])
{

	luavm = lua_open();
	lua_baselibopen(luavm);
	lua_dofile(luavm, "hello.lua");
	lua_close(luavm);

	return 0;
}

When this small program starts it will load up the "hello.lua" script and execute it. This is the very basic way of lua embedding, but I can't even make that work. Pretty disturbing.. because dlopen, dlclose, exp, sqrt and all others work just fine when using them from my own code, if you get what I mean. What's going on?? I bet there is some simple thing that I've done wrong, but I'm doing the best I can to fix it - which usually ends up in total disaster....

Hmm... I guess I'm the worst kind of newbie

eucharn · 07-03-2005, 12:35 AM

Worked my way around it, but it's not the easy way..

This setup works for the above posted code:

Code:

#include <dlfcn.h>

extern "C" {
	
#include "lua.h"
}


typedef int (*LUA_BASELIBOPEN)(lua_State*);	// luaopen_base (lua_baselibopen == macro)
typedef int (*LUA_DOFILE)(lua_State*, char*);	// lua_dofile

char *dlname = "liblualib.so";
char *luaname = "test.lua";

int main(int argc, char *argv[]) {
	
	void		*lualib;
	lua_State	*luavm;
	
	lualib = dlopen(dlname, RTLD_LAZY);
	luavm = lua_open();
	
	LUA_BASELIBOPEN lua_baselibopen = (LUA_BASELIBOPEN)dlsym(lualib, "luaopen_base");
	LUA_DOFILE lua_dofile = (LUA_DOFILE)dlsym(lualib, "lua_dofile");
	
	lua_baselibopen(luavm);
	lua_dofile(luavm, luaname);
	
	return 1;
}

Awful..but working. I would really like to use those static libs

POW R TOC H · 07-16-2008, 04:36 PM

I had the exact same problem

Just add these options :
-ldl -lm
and it will do just fine.