[boost] Re: boost::execution_monitor impl under windows

From: David Abrahams (dave_at_[hidden])
Date: 2003-10-08 19:20:12

Alexander Terekhov <terekhov_at_[hidden]> writes:

> David Abrahams wrote:
> [...]
>> We all agree that termination is appropriate when an invariant is
>> broken.  What we don't agree on is the ability of outer-level calls to
>> determine that an invariant is broken based on the type of exception
>> thrown from an inner-level call.  I believe that goes to the heart of
>> my objections to ESes.
>
> Well, 
>
> <quote> 
>           Consider the following example (only slightly contrived).
>
>           X get(int i) throw(out_of_range);
>           int find(X& x) throw()
>           {
>             for (int i = 0; i < size(); ++i) {
>               if (x == get(i)) return i;
>             }
>             return -1;
>           }
>
>           ....
>
>           Maybe the programmer knows that the function will never be 
>           called, or that the path containing the throw statement will 
>           never be executed.
>                             ^
> </quote>                    |
>                             |
> .. if nothing goes wrong! --+
>
> http://www.bleading-edge.com/Publications/C++Report/v9607/Column2.rtf

Sure, this is an edge case.

Furthermore, my point is that it's almost impossible for the library
to add any unwinding actions which could interact badly with a problem
knowable only by the caller, and only at the point where the library
decides to throw.  

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com