Lua调用C++

基于前文《C++调用Lua》继续探索Lua调用C++函数的问题：

test_lua_call_cpp.cpp文件：

#include <stdio.h>
extern "C"{
#include "lua.h"
#include "lualib.h"
#include "luaxlib.h"
};


lua_State* L;
//这个函数将被Lua调用
static int average(lua_State *L)
{
//得到Lua函数传入的参数个数
int n = lua_gettop(L);
double sum = 0;
int i;
for (i = 1; i <= n; i++)
{
sum += lua_tonumber(L,i);
}
//向解释器的值栈中压入结果值
lua_pushnumber(L,sum / n);
lua_pushnumber(L,sum);
//指明返回参数有两个
return 2;


}


int main(int argc,char *argv[])
{
L = luaL_newstate();
luaopen_base(L);
luaL_openlibs(L);
luaL_loadfile(L,"add.lua");
lua_pcall(L,LUA_MULTRET,0);
//向解释器注册C++函数
lua_register(L,"cpp_average",average);
lua_getglobal(L,"cppGetAverageAndSum");


lua_pushnumber(L,10);
lua_pushnumber(L,20);
lua_pushnumber(L,30);
lua_pushnumber(L,40);
lua_call(L,4,2);


int sum = (int)lua_tonumber(L,-1);
lua_pop(L,1);
int avg = (int)lua_tonumber(L,1);


printf("Cpp Output The avg is %dn",avg);
printf("Cpp Output The sum is %dn",sum);


lua_close(L);
getchar();
return 0;
}

add.lua文件：

function add(x,y)
return x + y
end


function cppGetAverageAndSum(w,x,y,z)
avg,sum = cpp_average(w,z)
print("Lua Output The average is ",avg)
print("Lua Output The sum is ",sum)?
return avg,sum
end

运行结果：