warning C4275, C4271when using boost::noncopyable

From: Roman Savchenko (gmstima_at_[hidden])
Date: 2020-05-13 19:27:26

Hi All,

I'm trying to update from boost 1.62 to boost 1.73. Boost 1.62 was built
with VS15 140 toolchain with shared runtime (/MD) and as static lib. Boost
1.73 was built with VS19 140 toolchain with /MD and as static lib.

I have a class:

#include <boost/noncopyable.h>

class __declspec(dllexport) A : private boost::noncopyable

when I'm using 1.62 I do not have such warning.
when I'm using 1.73 I do have such warning.

I'll appreciate if anyone could help me to understand what I'm missing. Why
does new version of header generate this warning?

Thanks,
Roman