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

[Ted Baker]

> Please note that the example destructor above is also called on a 
> regular (non-exceptional) exit from the block in which the 
> remote_resource_holder lives.
> 
> Since, in that case, there is no exception 'in flight', a cancellation 
> exception thrown from remote_source->release() *will* be discarded, 

There can be no cancellation exception thrown in this case,
because cancellation is disabled during the destructor
execution.  (This what is required in Ada, by the way.)

> unless - in *all* such destructors - the code is changed to explictly 
> disable cancellation.

Yes.  You must diable cancellation in *all* destructors.

> In other words, non-sticky cancellation will break existing code, and 
> the replacement code will not be pretty.  IMHO, this is highly 
> undesirable - writing robust destructors is hard enough without these 
> complications.

Disabling cancellation in all destructors can be done automagically
by the compiler, so it will not break existing code.  The code will
only need to be recompiled.

--Ted