C调lua出错,返回c层打印错误信息.

内容如题目

lua代码如下:
file: test.lua

local c
c.a = 123

---

c代码如下:
file: test.c

#include 

#include "lua.h"
#include "lauxlib.h"
#include "lualib.h"

static int traceback( lua_State *L)
{
    const char *msg = lua_tostring(L,-1);
    if (msg)
    {
        /*打印发生错误时的堆栈信息,msg是错误信息,附加到打印的堆栈最前端
        1是指从第一层开始回溯
        这个函数之后,lua_tostring(L,-1)即可获取完整的堆栈和错误信息.
        */
        luaL_traceback(L,L,msg,1);
    }
    else
    {
        lua_pushliteral(L,"no message");
    }
}


int main(int argc, char ** argv)
{
    lua_State *L = luaL_newstate();
    luaL_openlibs(L);

    lua_pushcfunction(L,traceback);

    int r = luaL_loadfile(L,"test.lua");
    if (r != LUA_OK)
    {
        printf("loadfile fail, result: %d\n", r);
        return 0;
    }


    //第四个参数表示将错误信息msg传入栈1所在的函数(错误处理函数)
    r = lua_pcall(L,0,0,1);

    if (r != LUA_OK)
        printf("call err\n%s\n", lua_tostring(L,-1));    
    else
        printf("call succ\n");


    return 0;
}

---

complie:

gcc -o test test.c -llua -ldl -lm

---

run

./test

---

result:

call err
 test.lua:2: attempt to index local 'c' (a nil value)
stack traceback:
        test.lua:2: in main chunk

错误信息包含文件,出错行号,错误原因,调用栈.