Determining object's class name at runtime

Determining object's class name at runtime

[Eilmsteiner Reinhard]

 
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Hi!

Is there a way (with gcc 3.2) to determine the class name of an object at
runtime? Or moreover ist pedigree?
Something like:

...
class A;
class B: public A;
...
A* pA;
...
pA->GetClassName (); or CLASSNAME (pA);
and
pA->IsKindOf("A"); or ISKINDOF(pA, "A");

Thx,
Reinhard Eilmsteiner

-----BEGIN PGP SIGNATURE-----
Version: PGPfreeware 7.0.3 for non-commercial use <http://www.pgp.com>

iQA/AwUBPkEngFaO5+5ahqodEQINlQCcDVuSVmypnQdg1SdrIKBIeTBK3vUAn0e/
uUCrJokIySjDbf9oA979JUtp
=RQCR
-----END PGP SIGNATURE-----

Re: Determining object's class name at runtime

[John Love-Jensen]

Hi Reinhard,

>Is there a way (with gcc 3.2) to determine the class name of an object at
runtime?

Yes.  Given your example:

class A;
class B : public A;

const type_info* tA = &typeid(*pA); // Get the type information.
cout << tA->name(); // Textual (probably mangled) CLASSNAME.
bool match = dynamic_cast<A*>(pA) != NULL; // Check ISKINDOF.

All these are explained in Section 15.4 of Stroustrup's C++PL (3rd ed or
Special ed).

If you find that you need to use these kinds of constructs a lot, you may
want to consider using a more appropriate language or reconsider your
applications design.  It may be that you are not using the OO facilities as
much as you should.  (If you need this mechanism for callbacks or passing
things through the OS API or across a C ABI, then that's apropos.)

Perl, Java, Lisp/Scheme/CLOS, Objective-C are all good choices.

--Eljay