Re: Overriding std::exception

From:
Miles <semanticist@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Wed, 16 Apr 2008 23:34:22 -0700 (PDT)
Message-ID:
<25882683-c6d6-4bda-8065-611aef2bf2ae@8g2000hsu.googlegroups.com>
On Apr 17, 2:15 am, pelio <pe...@liticom.ar> wrote:

Miles dixit:

Hello all,

When I subclass std::exception and throw an instance of the subclass,
when I call the what() method of the caught exception, it does not
call the overridden method. I'm under the impression that
std::exception declares what() as a virtual method, so I'm at a loss
as to why the subclass's what() is not being called. For example, for=

this program:


http://www.parashift.com/c++-faq-lite/exceptions.html#faq-17.10


Thank you for your response, but that doesn't explain what I'm
seeing. The FAQ entry is about throwing a reference to an object when
the apparent type of an object is different from its actual type at
the point at which it is thrown. I know that an object of the correct
type is being thrown, because std::exception::what returns the
typeid().name() of the object of the correct class.

    try {
        throw Exception2();
    } catch (std::exception &e) {
        std::cerr << e.what() << std::endl;
    }

In that catch block, e is a reference to an Exception2 object (I've
verified this with typeid()), but its what() method is not being
called--it is behaving as if what() were not virtual, but according to
everything I can find, std::exception::what() *is* virtual.

Thanks,
Miles

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