"Undefined reference to" using Lua

Question

I got the error undefined reference to 'luaL_newstate' when I try to build my project. I know it's an error with the linker but I'm relatively new to Lua and adding a library to a project. I use Code::Blocks by the way. API functions luaL_openlibs, luaL_loadfile, lua_pcall, lua_getfield, lua_type, lua_settop are missing too.

I saw on a webite that I have to link my project with libdl in order to solve this problem, but I don't really know what it mean and how to do it.

Answer 1

I faced the same problem, in my case I found a solution that worked for me here. Basically consist in wrapping the #include s of lua inside a extern "C", like:

extern "C"{
    #include <lua5.2/lualib.h>
    #include <lua5.2/lauxlib.h>
    #include <lua5.2/lua.h>
}

Answer 2

Lua can be a bit complex when you're first trying to compile it. The website that you referenced was correct: libdl is pretty much required when linking Lua.

I don't have Code::Blocks in front of me, so I can't really tell you what options you need to add. It should be a list of "command line options" or "compiler options". If you were compiling from the command line, the full command would look like:

gcc -o sample sample.c -llua -ldl

Note that the -l options have no space before the library name. There should be an option in Code::Blocks to add your own compile-time options or compiler flags. You would add "-llua" and "-ldl" to that options list. Alternatively, just do it yourself from the command line.

libdl is a library that is used when dynamically linking other libraries into your program. You have to add it in for Lua to be linked correctly.