Re: is it possible to make longjmp-free Lua?

["Juris Kalnins" <juris@...>]

On Mon, 27 Jul 2009 12:55:23 +0300, Juris Kalnins <juris@mt.lv> wrote:

> > Lua error mechanism only require setjmp/longjmp, not C++ exceptions.
> > Are you sure -fexceptions is needed for setjmp/longjmp to work ? IIRC
> > -fexceptions generate data needed for destructors to be called, which
> > setjmp/longjmp and thus Lua error mechanism do not need.
>
> But c++ does need it. It runs destructors on function exit. You cannot  
> simply discard stack frames in C++. (And see above example for why it is  
> bad for C, too).

Sorry, this reply was unnecessarily terse. To clarify: problem is not that  
setjmp doesn't work with -fno-exceptions, but that C++ throw/catch cannot  
be used with -fno-exceptions, and thus any Lua exception that unwinds C++  
stack frame is an error. In other words, it is not possible to call most  
of Lua API from C++ functions that have non-trivial local variables, if  
Lua doesn't use C++ throw for exception handling.