Re: [boost] Re: Boost.Assertion

From: Jesse Jones (jesjones_at_[hidden])
Date: 2001-04-18 18:03:28

At 7:42 AM -0400 4/18/01, David Abrahams wrote:
>----- Original Message -----
>From: "Jesse Jones" <jesjones_at_[hidden]>
>
>>  I thought std::uncaught_exception() was pretty much worthless, but I
>>  confess I don't know all the details (and the archives don't have
>>  much to say). Can we really use this inside a dtor to see if the
>>  stack is being unwound because of an exception?
>
>Yes (if the compiler conforms). The problem with uncaught_exception() is
>that it won't detect the case where you're inside a catch block which is
>going to rethrow the exception:
>
>try {
>}
>catch(...) {
>   // cleanup actions...
>   // <=== uncaught_exception() is false here
>   // more cleanup actions...
>   throw;
>}
>
>This condition is almost the moral equivalent of being inside a destructor
>during stack unwinding: the supposedly neccessary "more cleanup actions"
>won't be executed if you rethrow here. Also, the active exception is lost.

Hmm, well that's still useful. For example, it makes file classes a 
bit easier to write. Instead of using a close() method you can do the 
close in the dtor. If an error is returned you can throw if 
uncaught_exception() returns true. Too bad CodeWarrior doesn't 
support it...

   -- Jesse