luaとcの相互作用について簡単に説明します。

lua_State *L = luaL_newstate();//create a new stack

lua_pushstring(L, "muzixiaoxin"); //push a string onto the stack
lua_pushnumber(L, 875);//push an integer onto the stack

//now there are two elements on the stack, the bottom of the stack is the string "muzixiaoxin", the top of the stack is the integer 875
//"muzixiaoxin" the index is 1, or -2
//the index of 855 is 2, or -1

if (lua_isstring(L, 1)){//Determine if the element at the bottom of the stack is a string
  printf("%s\n",lua_tostring(L, 1));//If it is a string, convert to string output
}

if (lua_isnumber(L, -1)){//Determine if the element at the top of the stack is of type number
  printf("%d", lua_tonumber(L, 2));//if it's a number, output it as a number
}

lua_close(L); //remember to release when not needed

name = "muzixiaoxin"
version = 1003

lua_State *L = luaL_newstate();

int err = luaL_loadfile(L, "test.lua"); //load the lua file as a block of code, just load it without running it
if (err){
  return;
}

err = lua_pcall(L, 0, 0, 0);//run the loaded code block
if (err){
  return;
}

lua_getglobal(L, "name"); //press the value of the global variable name to the top of the stack
printf("%s\n", lua_tostring(L, -1));//take out the top element of the stack and print the result as:muzixiaoxin

lua_close(L); //remember to release when not needed

// Calculate the summation method
static int
sum(int a, int b){
  return a + b;
}

//lua calls the method
static int
lsum(lua_State *L){
  int a = (int)lua_tonumber(L, -1);//one of the parameters of the lua call
  int b = (int)lua_tonumber(L, -2);//one of the arguments to the lua call
  lua_pushnumber(L, sum(a, b));//add the calculated to the stack
  return 1;//return the number of returned values
}

lua_State *L = luaL_newstate();

luaL_openlibs(L);//open all the standard libraries in L so that you can use the print method

lua_register(L, "sum", lsum);//register the c function lsum as a global variable sum of lua

int err = luaL_dofile(L, "test.lua"); //load the lua file as a block of code and run it
if (err){
  return;
}

lua_close(L);

print("1 + 2 = " . sum(1,2))

1+2=3