[c++-pthreads] Re: cancellation points report failure

[Alexander Terekhov]

Fergus Henderson wrote:
[...]
> > > Asynchronous cancelability only works if you can be sure that there
> > > are no implicit calls to async-cancel-unsafe functions going on.
> >
> > Yep (and probably also C++ things like throw-expressions and "try
> > {").
> 
> "probably" is the word. 

I said "probably" because apart from inherently async-cancel-unsafe
operations/functions like operator new()/operator delete() (and
alike), a smart compiler understanding the meaning of async_cancel{} 
and sync_cancel{} (and also no_cancel{}) "probably" can translate 
things like

void f() async_cancel_safe {
  /*...*/
  sync_static T t(/*...*/); // synchronizised local static
  t.async_cancel_safe_operation();
}

to

void f() async_cancel_safe {
  /*...*/
  sync_cancel {
    sync_static T t(/*...*/); // synchronizised local static
    async_cancel {
      t.async_cancel_safe_operation();
    }
  }
}
 
>                         That's what I mean -- in C++, you can't even
> tell which language constructs might be implemented with code which
> under-the-hood is going to be doing dynamic memory allocation or other
> async-cancel-unsafe operations.

So, you really want to me stick to POF*** not only for signal
handlers, but also for async-cancel-safe regions? Well, thankyou.

regards,
alexander.

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     (Subject: Re: Thread function and C++)