Re: why not use naked delete ?

From:

Bo Persson <bop@gmb.dk>

Newsgroups:

comp.lang.c++

Date:

Fri, 26 Dec 2014 13:11:54 +0100

Message-ID:

<cg51kbF6eklU1@mid.individual.net>

On 2014-12-26 11:58, arnuld wrote:

After 5 years of working purely in C, finally I becawe jobless and have
some time on my hands to start C++. Well, I kept on peeking into
stroustrup from time to time but now I see with C++14 everything has
changed. Even in C++, I will allocate memory using /new/ and then free it
using /delete/ but now I see Stroustrup does not seem to agree to that:

http://isocpp.org/blog/2014/12/myths-2

He is calling it naked delete. I know there lot of other examples he has
given but those are using generic/oo programming(half of that code is
incomprehensible to me because IU just started C++ today). I am more
concerned with simple procedural subset of C++:

     X* p = new X;
     X* q = p;
     delete p;
     // ...
     q->do_something(); // the memory that held *p may have been re-used

STROUSTRUP: Don???t do that. Naked deletes are dangerous

ARNULD: then what I should do ?

Can someone point me to some direction in understanding this ?

Another part of the advice is not to use naked pointers either. :-)

Stroustrup shows how to use a unique_ptr when you need a single pointer
to an object. There is also a shared_ptr for when you want to share
ownership of the object. In both cases, the object is automagically
deleted when the last pointer goes away.

You could do:

    auto p = std::make_shared<X>();
    auto q = p;

    // do something that invalidates p

    q->do_something(); // q is still valid here

Bo Persson