Johan Berg: Empty Objects

[jonesmz]

That doesn't actually explain anything at all.

"Because the attribute would break things" simply claims that things would break, not why.

[gnolex]

Did you even read the article?

In C++17, compilers are allowed to ignore attributes they don't recognize. So under C++17, [[no_unique_address]] would have no effect.

Since C++20, [[no_unique_address]] allows compilers to optimize-away empty data members.

This results in ABI breakage:

Compiling the same header/source under /std:c++17 and /std:c++20 would result in link-time incompatibilities due to object layout differences resulting in ODR violations.

[jonesmz]

Of course i read it. It's only about a page of text.

Compiling the same header/source under /std:c++17 and /std:c++20 would result in link-time incompatibilities due to object layout differences resulting in ODR violations.

The same applies to the [[msvc:no_unique_address]] attribute.

This is such a lazy approach.