Re: [c++-pthreads] Re: thread-safety definition

[Jason Merrill <jason@xxxxxxxxxx>]

On Sun, 11 Jan 2004 22:03:58 +0100, Wil Evers <wil@xxxxxxxxxxxxxx> wrote:
> Jason Merrill wrote:

>> I agree that cancellation should be sticky, and it is in my model as well
>> as Nathan's.  But I don't think that this particular example would discard
>> cancellation exceptions.
>
> I think it will.  Even if cancellation is disabled while exceptions are in
> flight, a 'catch-everything-and-never-rethrow' block in a destructor will
> discard a cancellation exception when that destructor is triggered by a
> regular (non-exceptional, non-unwinding) exit from a block scope.

True.

> Call me paranoid, but as a C++ programmer, the thing that scares me most in
> the discussions on this list is a certain (perceived?) pressure to open the
> door for letting exceptions escape from destructors.

I don't think anyone is advocating that.  I can see how you could infer
that from general opposition to catch(...) { }, but destructors are a
situation where it is appropriate, as the alternative is terminate().

This is why I want the cancel to return to pending status if the exception
is destroyed--so that exception-safety code like this doesn't result in the
unexpected loss of a cancel.

Jason