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From: jgro@lia (Jeremy Grodberg)
Newsgroups: comp.lang.c++
Subject: Re: Distinguishing stack and heap objects
Message-ID: <1991Jan7.231403.318@lia>
Date: 7 Jan 91 23:14:03 GMT
References: <1990Dec29.013620.23761@sjsumcs.sjsu.edu>
Reply-To: jgro@lia.com (Jeremy Grodberg)
Lines: 36

In article <1990Dec29.013620.23761@sjsumcs.sjsu.edu> horstman@sjsumcs.SJSU.EDU (Cay Horstmann) writes:
>Give class X a member int fromHeap and a static member int heapFlag. Define
>all constructors X::X( ... ) to contain the lines
>     fromHeap = heapFlag;
>     heapFlag = 0;
>and define X::operator new( size_t s ) as
>     {  heapFlag = 1;
>	return new char[s];
>     }
>
>If x is any pointer of type X*, then x->fromHeap is true iff x is allocated
>on the heap. I am using the fact that X::operator new is (acts like?) a
>static member function and hence can access static members of X.
>
>Is this legal? Is it in the spirit of the language? Is it useful? CAN I PATENT
>IT? 

Yes.
Maybe.
No.
No.


The real problem here is that whle this will work for

  X* x = new X(...);

It will not catch

  X* x = new X[10];

since that will use ::new, not X::new.

-- 
Jeremy Grodberg      "I don't feel witty today.  Don't bug me."
jgro@lia.com