boost::noncopyable does not prevent adding copy constructor to derived class

[Andreas Fenkart <afenkart@…>]

The documentation from boost::noncopyable is quite minimal. http://www.boost.org/doc/libs/1_55_0/libs/utility/utility.htm#Class_noncopyable ​http://stackoverflow.com/questions/7823990/what-are-the-advantages-of-boostnoncopyable

To my understanding the attached code shouldn't compile

$ gcc --version gcc (Debian 4.9.2-10) 4.9.2 Copyright (C) 2014 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[Andreas Fenkart <afenkart@…>]

class deriving boost::noncopyable and declaring copy constructor

[Marshall Clow]

My opinion on this is "close as not a bug".

We don't prevent people from acting maliciously.

noncopyable makes the copy constructor and assignment operators private (and doesn't implement them), so if you call them you get a compile (or link) error. If you go and implement your own copy constructor in a class that is derived from noncopyable, then my belief is that you wanted to be able to copy those objects.

[Andreas Fenkart <afenkart@…>]

Yup, seems I got the semantics wrong, boost::noncopyable is a macro, that spares some typing. I still have to ensure Foo contains no copy constructor, I hoped it would free me from checking that as well.

I retire the question

[Andreas Fenkart <afenkart@…>]

boost::noncopyable correctly working

[Marshall Clow]

Not really a macro - but a class that you inherit from to get certain behavior.

Because the behavior is inherited, you can override it if you choose.