type_info

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2 total messages Started by B. Dalton Wed, 17 Jan 1996 20:22

#3029

Author: B. Dalton
Date: Wed, 17 Jan 1996 20:22

31 lines
1498 bytes

The April draft says(see 
http://www.cygnus.com/misc/wp/draft/lib-support.html#lib.support
.rtti) about type_info::operator==

  bool operator==(const type_info& rhs) const;

  Effects:
    Compares the current object with rhs.
  Returns:
    true if the two values describe the same type.

What does "same" mean here? To be specific, say we had
...
class beatha{public:virtual ~beatha(){};}
class duine:public beatha{};
class gael: public duine {};

beatha *pd=new gael;
if(typeid(pd)==typeid(duine)
{	cout<<"duine";
}
...
does "duine" get printed here or not?

-- 
B. Dalton         DEC - Gaillimh
mailto:bdalton@xagony.ilo.dec.com
---
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Re: type_info

#3036

Author: David Vandevoorde
Date: Thu, 18 Jan 1996 02:41

21 lines
1330 bytes

>>>>> "BD" == "B Dalton" <bdalton@xagony.ilo.dec.com> writes:
BD> class beatha{public:virtual ~beatha(){};}
BD> class duine:public beatha{};
BD> class gael: public duine {};

BD> beatha *pd=new gael;
BD> if(typeid(pd)==typeid(duine)
BD> {	cout<<"duine";
BD> }
BD> ...
BD> does "duine" get printed here or not?

No, it doesn't since typeid(pd) = typeid(beatha*).
You probably meant `if(typeid(*pd)==typeid(duine)) ...',
but even then the answer is `no': typeid(*pd)==typeid(gael).

	Daveed
---
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