Extending Lua

[Ervin Hegedüs <airween@...>]

Hi Folks,

I'ld like to extend Lua (with a new module), with an existing C codes. I'm using Lua 5.2 on Linux.

Here is how I try:

==%==
luamodule.c:
-------------------
#include "lua.h"
#include "luaconf.h"
#include "lauxlib.h"

#include "example1.h"  // contains variable and function declarations

static int _wrap_get_str (lua_State *L) {
    const char *s = luaL_checkstring(L, 1);
    char retstr[1024];

    get_str(s, retstr);
    printf("retstr: '%s'\n", retstr);
    return 0;
}

void luaopen_example2(lua_State *L) {
    static const struct luaL_Reg example2[] = {
      { "get_str", _wrap_get_str },
      { NULL, NULL }
    };
    luaL_newlib(L, example2);
    lua_setglobal(L, "example2");
}
==%==

Compiling with this statement:
gcc -g -Wall -shared -fPIC example1.c luamodule.c -o example2.so -I/usr/include/lua5.2 -llua5.2 -lm -ldl

My Lua script:

==%==
#!/usr/bin/lua

example2 = require("example2")
==%==

and then the example2 will be a "true" (boolean) evaulated variable, not a table. So, when I calling example2.get_str("foo"), then I get an error message:

attempt to index global 'example2' (a boolean value)

What's wrong with my code?

Thanks,

a.