From: Jack Klein <jackklein AT spamcop DOT net>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: void* conversions & delete
Message-ID: <DmDFOcQB6HcHcteeI9qbj30QmLqv@4ax.com>
References: <8q3f52$1bc$1 AT info DOT cyf-kr DOT edu DOT pl>
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Date: Mon, 18 Sep 2000 00:22:15 GMT
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On Mon, 18 Sep 2000 00:00:14 +0200, "Rafał Maj" <r_maj AT poczta DOT onet DOT pl>
wrote in comp.os.msdos.djgpp:

> Hi,
> is this code correct :
> 
> int *pos = new int[2];
> void* var = (void*)pos;
> delete []((int*)var);
> 
> I'm not sure, will everything be o.k. when I'll temporarly store adress of
> int[] array    in    void*
> If this example has bug, how to fix it ?
> 
> Thanks,
> Rafal

This is perfectly OK as long as you use the proper type of pointer
when you use delete or delete[] on it.

Both C and C++ guarantee that:

1.  You can store a pointer to any object type in a pointer to void
(requires a cast in C++, not in C).

2.  Assign or cast that pointer value back to a pointer to the
original type.

3.  The final result will point to the same object.

So assigning pos to a pointer to void, and casting that pointer to
void back to pointer to int produces a pointer to int that still
points to the first of the two ints allocated to pos.

Jack Klein
-- 
Home: http://jackklein.home.att.net