I don't really know luabind, so I'm not sure, if they offer any of their own facilities to do that, but in Lua you'd do that like this:
int myLuaFunc(lua_State *L)
{
int arg1 = luaL_toint(L, 1);
luaL_checktype(L, 2, LUA_TTABLE); //Throws an error, if it's not a table
luaL_checktype(L, 3, LUA_TTABLE);
//Get values for the first table and push it on the stack
lua_getfield(L, 2, "keyname"); //Or use lua_gettable
//Assuming it's a string, get it
const char *tmpstr = lua_tostring(L, -1);
//..... Similariliy for all the other keys
}
You might want to refer to Lua Reference Manual for description of the functions I used.