Re: Catching exceptions

On Fri, Apr 29, 2011 at 11:28 AM, Josh Klint <[email protected]> wrote:

> I created a C++ function to throw an exception:
>
>
>
> void RuntimeError(const std::string& error)
>
> {
>
>       throw std::exception(error.c_str());
>
> }
>
>
>
>
>
> Here is the Lua script that calls it:
>
>
>
> print("Creating an error...")
>
>
>
> RuntimeError("An error has occurred!")
>
>
>
>
>
> Here is the code that runs the script.  Instead of catching the exception,
> lua_pcall returns non-zero and the Lua string at the top of the stack
> contains "std-exception: 'An error has occurred!'":
>
>
>
> bool Interpreter::Invoke(const int& in, const int& out)
>
> {
>
>       try
>
>       {
>
>             if (lua_pcall(L,in,out,0)==0)
>
>             {
>
>                   return true;
>
>             }
>
>             else
>
>             {
>
>                   //If you throw an exception, it gets displayed here,
> which isn't what we want:
>
>                   HandleError();
>
>             }
>
>       }
>
>       //Exceptions should be getting caught here:
>
>       catch(luabind::error& e)
>
>       {
>
>             Print("Caught the exception!");
>
>             exit(1);
>
>       }
>
>       return false;
>
> }
>
>
>
>
>
> I am using MSVC, and I know about the issue described below.  The code they
> said to add has no effect on behavior:
>
>
> http://www.rasterbar.com/products/luabind/docs.html#structured-exceptions-msvc
>
>
>
> What do I have to do to make my program catch the exception thrown by the
> C++ function the Lua script calls?  Thanks.
>

If you have built Lua as C (which is typical) rather than C++, exceptions
can't be thrown "through" stack frames with Lua calls - it wouldn't work.
So, Luabind catches all exceptions from C++ code called by Lua code, then
propogates them as Lua errors (which is what you're seeing - message on top
of the stack, etc). See
http://www.rasterbar.com/products/luabind/docs.html#exceptions

<http://www.rasterbar.com/products/luabind/docs.html#exceptions>Ryan

-- 
Ryan Pavlik
HCI Graduate Student
Virtual Reality Applications Center
Iowa State University

[email protected]
http://academic.cleardefinition.com
Internal VRAC/HCI Site: http://tinyurl.com/rpavlik

------------------------------------------------------------------------------
WhatsUp Gold - Download Free Network Management Software
The most intuitive, comprehensive, and cost-effective network 
management toolset available today.  Delivers lowest initial 
acquisition cost and overall TCO of any competing solution.
http://p.sf.net/sfu/whatsupgold-sd

_______________________________________________
luabind-user mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/luabind-user