Re: [basic-improvements] try/finally support for c/c++ - more tests

[Geoff Keating <geoffk@geoffk.org>]

> Date: Thu, 07 Nov 2002 12:29:46 -0800
> From: Mark Mitchell <mark@codesourcery.com>
> 
> --On Thursday, November 07, 2002 12:18:33 PM -0800 Geoff Keating 
> <geoffk@geoffk.org> wrote:
> 
> > Mark Mitchell <mark@codesourcery.com> writes:
> >
> >> We're trying to implement one particular piece of functionality required
> >> by the POSIX threads interface; namely "pthread_cleanup_push" and
> >> friends. (I know that any feature might get used more widely, but this
> >> is the motivation, as I understand it.)  Furthermore, we're trying to
> >> make the POSIX threads cleanups play nice with exception-handling.
> >
> > Yes, this is right, but your example is not the case we really care
> > about.  What we particularly want to make work is this C++ code:
> >
> > struct A { ~A() { ... } };
> >
> > {
> >   A foo;
> >   sigpause ();  // cancellation point, I hope
> > }
> 
> > Here, if 'sigpause' gets cancelled, we want A's destructor to not be
> > run.
> 
> I think you mean you want it *to* be run?

Yes.

> These kinds of cases are easily handled by my #ifdef __cplusplus idea
> for the pthread_cleanup_push definition.

How?  There aren't any pthread_cleanup_push calls in the example.
You'd have to have sigpause (and the other cancellable calls)
conditionalised on __cplusplus, and then to permit users to write
programs in a mix of C and C++ you'd have to define some way to
convert the exceptions thrown in C++ to the sj/lj calls in C.

-- 
- Geoffrey Keating <geoffk@geoffk.org>