Re: Libification project (SoC)

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Mar 16, 2007, 11:51 UTC
Message-ID: <Pine.LNX.4.63.0703161248380.22628@wbgn013.biozentrum.uni-wuerzburg.de>
In-Reply-To: <vpqveh15zvn.fsf@olympe.imag.fr>

Hi,

On Fri, 16 Mar 2007, Matthieu Moy wrote:

Show 22 quoted lines

> Johannes Sixt <J.Sixt@eudaptics.com> writes:
> 
> > You could think about longjmp(3)ing out into main(), which would have to
> > setjmp(3). But in order to clean up intermediate frames, you would have
> > to have a stack of setjmp/longjmp buffers.
> >
> > Oh, well, how do I *love* them C++ exceptions!
> 
> You can have exceptions in C too.
> 
> I've used it a bit while contributing to Baz 1.x (the fork of tla).
> The library used was cexcept ( http://cexcept.sourceforge.net/ ).
> 
> As you mention, jumping is the easy part, and cleaning up is the hard
> one. Baz was using talloc, hacked to somehow work with cexcept. The
> mini-library doesn't seem to be available as a tarball anymore, so I
> did the checkout+targz in case someone's curious to have a look, and
> lazy enough not to install baz to get it:
> 
> http://www-verimag.imag.fr/~moy/tmp/talloc-except--2.0.1--patch-2.tar.gz
> 
> This stuff is not supported anymore, but very small anyway.

I was thinking about a similar approach some time ago. But that means that you _must not_ have static variables that you rely on being initialised correctly.

I mean, we have xmalloc(), and it would be easy to enforce xfree(), too (which would be good for memory profiling anyway), and we _could_ hack that into tracking which pointers were returned after which checkpoint.

But we _cannot_ say which static variables should be initialised (and how), after some "exception" was thrown at a certain point.

Ciao, Dscho