Re: Lua 5 stack traceback / unwind

[Wim Couwenberg <w.couwenberg@...>]

> In lua 5, we are using luaL_loadbuffer followed by lua_pcall.  If there
> is an error, there is no stack trace back.
>
> How do we implement this in lua 5?

Have a look at debug.traceback, it is also stored under the global name 
_TRACEBACK (in 5.0.2 at least, didn't check 5.1).  You can provide it as 
an error handler in lua_pcall something like this:

    /* stack layout:  func arg1 ... argn */

    /* provide traceback function */
    lua_pushstring(L, "_TRACEBACK");
    lua_gettable(L, LUA_GLOBALSINDEX);
    lua_insert(L, -n - 2);

    /* stack layout:  _TRACEBACK func arg1 ... argn */

    /* call func with error handler */
    if (lua_pcall(L, n, 0, -n - 2))
    {
        /* an error with stack traceback is now at tos */
    }

The traceback function will still be on the stack after lua_pcall.

--
Wim