Re: static_cast vs reinterpert_cast

From:

Rolf Magnus <ramagnus@t-online.de>

Newsgroups:

comp.lang.c++

Date:

Mon, 10 Jul 2006 11:14:14 +0200

Message-ID:

<e8t5oo$vf$00$1@news.t-online.com>

Rahul wrote:

Hi,

I have a
class A : public B {...member functions......data members};

and am doing the following
    A *p=new A();
    void *p=static_cast<void *>(p);
    factory_instance->process(p);

Here p is passed to a function, which accepts void ptr.

No need for a static_cast. You can convert a pointer to an object into a
pointer to void implicitly.

That function
need to cast it back
A *pp=static_cast<A *>(p);

The function is in the factory which accepts void *p only, the specific
implementations need to cast the pointer back to the expected class
and use it.

Question:Though both works fine, yet I want to know what is more
appropriate in this situation static_cast OR reinterpert_cast

static_cast. Generally, one could say that you should choose static_cast
over reinterpret_cast if it does the job.

The books suggests
static_cast=> "For "well-behaved" and "reasonably
well-behaved" casts,including things you might now do without a cast
reinterpret_cast=> To cast to a completely different meaning. The key
is that you'll need to cast back to the original type to use it
safely.

But I am not able to interpret the sentences in this context :-)

You could translate it to "reinterpret_cast is more evil than
static_cast" ;-)