• Source: Lucas Klassmann blog

Examples

#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>

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

    lua_State *L = luaL_newstate();
    luaL_openlibs(L);

    // Work with lua API

    lua_close(L);
    return 0;
}

#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>

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

    lua_State *L = luaL_newstate();
    luaL_openlibs(L);

    // Our Lua code, it simply prints a Hello, World message
    char * code = "print('Hello, World')";

    // Here we load the string and use lua_pcall for run the code
    if (luaL_loadstring(L, code) == LUA_OK) {
        if (lua_pcall(L, 0, 0, 0) == LUA_OK) {
            // If it was executed successfuly we 
            // remove the code from the stack
            lua_pop(L, lua_gettop(L));
        }
    }

    lua_close(L);
    return 0;
}

(Note that Lucas' blog contains a typo: his code has a lower case l in lua_gettop(L) which doesn't compile.)

Makefile

all: a b

%: %.c
    gcc -o $@ $< -I/usr/include/lua5.4 -llua5.4

dofile

We can already execute lua files.

#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>

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

    lua_State *L = luaL_newstate();
    luaL_openlibs(L);

    // Work with lua API
    char * code = "dofile('hello.lua')";

    // Here we load the string and use lua_pcall for run the code
    if (luaL_loadstring(L, code) == LUA_OK) {
        if (lua_pcall(L, 0, 0, 0) == LUA_OK) {
            // If it was executed successfuly we
            // remove the code from the stack
            lua_pop(L, lua_gettop(L));
        }
    }

    lua_close(L);
    return 0;
}

Shared Library

// exl001.c
#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>
#include <stdlib.h>

typedef struct {
  lua_State* state;
} MyLua;

MyLua* create_my_lua() {
  MyLua* mylua = (MyLua*)malloc(sizeof(MyLua));
  mylua->state = luaL_newstate();
  luaL_openlibs(mylua->state);
  return mylua;
}
void destroy_my_lua(MyLua* mylua) {
  lua_close(mylua->state);
  free(mylua);
}


static void test1(MyLua* mylua);
void test() {
  MyLua *mylua = create_my_lua();

  test1(mylua);

  destroy_my_lua(mylua);
}

static void test1(MyLua* mylua) {
    char * code = "dofile('hello.lua')";
    lua_State* L = mylua->state;

    // Here we load the string and use lua_pcall for run the code
    if (luaL_loadstring(L, code) == LUA_OK) {
        if (lua_pcall(L, 0, 0, 0) == LUA_OK) {
            // If it was executed successfuly we
            // remove the code from the stack
            lua_pop(L, lua_gettop(L));
        }
    }
}

// hello.lua
print("Hello, World! Woohoo!")

import ctypes
lib = ctypes.cdll.LoadLibrary("./exl001.so")
test = lib.test
test()

all: exl001.so

exl001.so: exl001.c
    gcc -I /usr/include/lua5.4 -o $@ $< -shared -llua5.4