Lua with c++

main.cpp

extern "C"{
#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"
}
#define err_return(num,fmt,args...) do{printf("[%s:%d]"fmt"\n",__FILE__,__LINE__,##args);return(num);} while(0)
#define err_exit(num,fmt,args...) do{printf("[%s:%d]"fmt"\n",__FILE__,__LINE__,##args);exit(num);} while(0)

using namespace std;
int csum(lua_State* l)
{
    int a = lua_tointeger(l,1) ;
    int b = lua_tointeger(l,2) ;
    lua_pushinteger(l,a+b) ;
    return 1 ;
}
int main()
{
    lua_State* luaState = luaL_newstate() ;        //創建lua運行環境
    if (luaState == NULL) err_return(-1,"luaL_newstat() failed");
    int ret = 0 ;
    ret = luaL_loadfile(luaState,"func.lua") ;      //加載lua腳本文件
    if (ret != 0) err_return(-1,"luaL_loadfile failed") ;
    ret = lua_pcall(luaState,0,0,0) ;
    if (ret != 0) err_return(-1,"lua_pcall failed:%s",lua_tostring(luaState,-1)) ;
    //----------------------------------------------------------------------------------------
    lua_getglobal(luaState,"width");  //-2           //獲取lua中定義的變量
    lua_getglobal(luaState,"height"); //-1
    printf("height:%ld width:%ld\n",lua_tointeger(luaState,-1),lua_tointeger(luaState,-2)) ;
    lua_pop(luaState,1) ; //恢復lua的棧
    //----------------------------------------------------------------------------------------
    int a = 11 ;
    int b = 12 ;
    lua_getglobal(luaState,"sub");               //調用lua中的函數sub
    lua_pushinteger(luaState,a) ;
    lua_pushinteger(luaState,b) ;
    ret = lua_pcall(luaState,2,1,0) ;  //a-b
     if ( ret != 0 ) err_return(-1,"lua_pcall failed:%s",lua_tostring(luaState,-1)) ;
    printf("sum:%d - %d = %ld\n",a,b,lua_tointeger(luaState,-1)) ;
    lua_pop(luaState,1) ;
    //----------------------------------------------------------------------------------------
     const char str1[] = "hello" ;
    const char str2[] = "world" ;
    lua_getglobal(luaState,"mystrcat");          //調用lua中的函數mystrcat
    lua_pushstring(luaState,str1) ;
    lua_pushstring(luaState,str2) ;
    ret = lua_pcall(luaState,2,1,0) ;
    if ( ret != 0 ) err_return(-1,"lua_pcall failed:%s",lua_tostring(luaState,-1)) ;
    printf("mystrcat:%s%s = %s\n",str1,str2,lua_tostring(luaState,-1)) ;
    lua_pop(luaState,1) ;
    //----------------------------------------------------------------------------------------
    lua_pushcfunction(luaState,csum) ;         //註冊在lua中使用的c函數
    lua_setglobal(luaState,"csum") ;           //綁定到lua中的名字csum
    lua_getglobal(luaState,"mysum");           //調用lua中的mysum函數，該函數調用本程序中定義的csum函數實現加法
    lua_pushinteger(luaState,a) ;
    lua_pushinteger(luaState,b) ;
    ret = lua_pcall(luaState,2,1,0) ;
    if ( ret != 0 ) err_return(-1,"lua_pcall failed:%s",lua_tostring(luaState,-1)) ;
    printf("mysum:%d + %d = %ld\n",a,b,lua_tointeger(luaState,-1)) ;
    lua_pop(luaState,1) ;

    lua_close(luaState) ;                     //釋放lua運行環境
    return 0 ;
}

func.lua

--變量定義
width=1 ;
height=2 ;
--lua函數定義，實現減法
function sub(a,b)
    return a-b ;
end
--lua函數定義，實現字符串相加
function mystrcat(a,b)
    return a..b ;
end
--lua函數定義，通過調用c代碼中的csum函數實現加法
function mysum(a,b)
    return csum(a,b) ;
end