[Development] QProperty and library coding guide

Giuseppe D'Angelo giuseppe.dangelo at kdab.com
Thu Jul 16 22:16:41 CEST 2020

Il 16/07/20 12:43, Volker Hilsheimer ha scritto:
> For pre-C++20 (where it’s possible to have zero-size structs), and for compilers that don’t respect the [[no_unqiue_address]] attribute, all these struct-instances are put into a union. In that case, a class using QProperty will be larger (by the same amount no matter the number of properties) than the same class in Qt 5. With C+++ 20 and compilers that do respect [[no_unique_address]], the size and layout of these classes will be the same.

I'm not fully understanding this last part -- does changing compiler 
break ABI, because the implementation of properties change (from an 
union to [[no_unique_address]] members)?


Giuseppe D'Angelo | giuseppe.dangelo at kdab.com | Senior Software Engineer
KDAB (France) S.A.S., a KDAB Group company
Tel. France +33 (0)4 90 84 08 53, http://www.kdab.com
KDAB - The Qt, C++ and OpenGL Experts

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