Re: zero memory

From:
ajk <usenetonly@doh.com>
Newsgroups:
comp.lang.c++
Date:
Sat, 07 Apr 2007 05:10:12 GMT
Message-ID:
<nb9e139rohn2rb9aslevlnabific4kirlh@4ax.com>
On Fri, 06 Apr 2007 05:39:34 -0700, Gianni Mariani
<gi3nospam@mariani.ws> wrote:

In this case, you're calling new on CMYSTRUCT and I expect that you'll
call delete on a MYSTRUCT. That's undefined. Bad things will happen if
don't modify that habbit.


why do you expect that? ok i have not added any virtual dtor as was
not providing a full class. just showing the principle.

}

or make the MYSTRUCT a class


MYSTRUCT is a class.


technically you are right, although what I meant was to make it a
"real" class with ctor/dtor etc.

I just thought of yet another way - this one will create a default
constructed or zero initialized POD object depending on what type of
pointer you're trying to assign it to.

struct InitObj
{
    template <typename T>
    operator T * ()
    {
        return new T();
    }
};

// usage - template automagically figures out which type to new
PMYSTRUCT * mys = InitObj();

int * z = InitObj();

Note the lack of a memset call and note that the code will work for POD
 types as well as non POD types.


ok that's in a way elegant, but a bit difficult for maintenance
programmers to troubleshoot

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