Re: [boost] Re: std::expected_exception

From: Peter Dimov (pdimov_at_[hidden])
Date: 2003-10-09 09:14:17

Alexander Terekhov wrote:
> Peter Dimov wrote:
>> Meaning "no, if there is throw() specification somewhere"? Duh. Of
>> course.
>
> Not necessarily throw().
>
> void oper() throw(int) {
>   /**/
>   fclose(/*..*/); // doesn't throw; cancel is unexpected
> }
>
> void oper() throw(int) {
>   /**/
>   try {
>     fclose(/*..*/); // can throw; cancel IS expected
>   }
>   catch (std::thread_cancel_request const &) {
>     /**/
>     std::enable_thread_cancel(); // re-enable cancel state
>     std::thread_self().cancel(); // re-inject cancel request
>     /**/
>   }
> }

OK. You want to use an exception specification that does not contain
thread_cancel_request as "syntactic sugar" for disable_cancelation. Why is
ES better than RAII in this context? What makes this technique useful for
other situations that involve a different kind of exception?