Q_DECLARE_SHARED: fix docs; require and use member-swap

By requiring a member-swap, this macro becomes applicable to a wider
range of types (e.g. QFont, which has another member besides 'd'),
while at the same time avoiding the encapsulation leak that is data_ptr().

There have been concerns over breaking existing users of
this macro, but for some time now, Q_DECLARE_SHARED only
works within QT_BEGIN_NAMESPACE anyway, so its a safe bet
that all users of this macro are in-tree.

Change-Id: I7fdd9dba204554af8d3f9768b97bb42847a5acf4
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

0 files changed, 0 insertions, 0 deletions