🚀 go-pugleaf

wchi@students.cs.mu.oz.au (Waye-Ian CHIEW) writes:

>   class General { };
>   class Specific : public General { };

>   int main () {
>      try { 
>	 throw New Specific;
>      }

>      catch ( General* general ) { }
>   }

>  
>This falls though without catching and aborts.  Why doesn't gcc match the Specific object to General?

As a guess, I would point out the fact that the General and Specific
classes are not polymorphic; by the ANSI C++ draft standard, a compiler
only has to do runtime type identification (surely in dynamic_cast<>,
but I believe in try/throw/catch too) for objects of classes that are
polymorphic (i.e., have at least one virtual function).  This is to
avoid mandating rtti's overhead on every object.  Try adding a virtual
function in General and see if that works as you expect (I don't have
a gcc with working exception handling so I can't test that myself).


Alex
--
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Cad.Lab S.p.A., v. Ronzani 7/29, 40033 Casalecchio (BO), Italia

Waye-Ian CHIEW <wchi@students.cs.mu.oz.au> writes:

|> Hello!
|>    class General { };
|>    class Specific : public General { };

|>    int main () {
|>       try { 
|> 	 throw New Specific;
|>       }

|>       catch ( General* general ) { }
|>    }

  
|> This falls though without catching and aborts.  Why doesn't gcc match the Specific object to General?

Without -frtti gcc only supports exact matches for catched objects.
-- 
Andreas Schwab                                      "And now for something
schwab@issan.informatik.uni-dortmund.de              completely different"