Re: lua_error() and C++

[Edwin Eyan Moragas <haaktu@...>]

let me just throw in my praises.
amazing! David, i am in love with your skill.
(Just had my dose of Samurai 7. sorry, can't
help it).

-- 
salud,
eyan


On 8/3/05, David Burgess <dburgess@gmail.com> wrote:
> Hello
> 
> >  How nicely (if at
> > all) does this play with C++'s unwinding? For example:
> >
> 
> Depends on your compiler. I can tell you what happens with MS VC6.
> I suspect similar issues with other compilers. This has been previously
> discussed on this list.
> 
> You need to compile your C++ with /EHsc-, this generates code that
> tells C++ that C can throw exceptions. Without this C++ code assumes
> that C will never throw an exception.
> 
> If you are going to be using Lua under a lot of C++ for a small
> performance hit you can replace the Lua longjmp code with
> try/catch and compile one Lua module as C++. This for shaky
> compilers puts all of the exception handling under one exception
> management mechanism.
> 
> I would be interested to know what is the current state of play with gcc.
> 
> For MS VC6 I did the following ( I can send you the complete patch
> if you like)
> 
> 1) copied ldo.c to ldo.cpp
> 2) In ldo.cpp added
> 
> class lua_exception {
>   int status;
> public:
>   lua_exception(int status_) : status(status_) { };
>   int get_status() { return status; }
> };
> 
> 
> 3) Changed
> 
> void luaD_throw (lua_State *L, int errcode) {
>   if (L->errorJmp) {
>     throw lua_exception(errcode);
>   }
>   else {
>     G(L)->panic(L);
>     exit(EXIT_FAILURE);
>   }
> }
> 
> int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) {
>   struct lua_longjmp lj;
>   lj.status = 0;
>   lj.previous = L->errorJmp;  /* chain new error handler */
>   L->errorJmp = &lj;
>   try {
>     (*f)(L, ud);
>   }
>   catch (lua_exception &e) {  /* an error occurred: restore the state */
>     lj.status = e.get_status();
>   }
>   catch (...) {
>     throw;
>   }
>   L->errorJmp = lj.previous;  /* restore old error handler */
>   return lj.status;
> }
> 
> 4) Compiled everything with /GX /EHsc-
> This has been working ok for me.
> 
> Finally Lua5.1 work6 has build time options for using try/catch rather
> than longjmp. The important point is that the exception handling is
> localized to ldo.c in two functions so that it is rather easy to install
> whatever exception handling mechanism that you prefer.
> 
> DB
>