Return a bool instead of an int & allow default interface to be selected

Own a reference instead, and document the behavior

This is likely to break under MSVC

The later is not portable

Also add the proper include file

Since MSVC doesn't handle SFINAE, it will report a build error instead of failing gracefully and use the default case.
Instead, we provide an explicit specialization for std::nullptr_t, so that the compiler won't complain about nullptr not being convertible to a function

MSVC doesn't support constructor inheritance so far

This also fix user callbacks perfect forwarding

Alexey Sokolov authored Apr 03, 2015 and Hugo Beauzée-Luyssen committed Apr 13, 2015

Signed-off-by: Hugo Beauzée-Luyssen <hugo@beauzee.fr>

Alexey Sokolov authored Apr 03, 2015 and Hugo Beauzée-Luyssen committed Apr 13, 2015

Signed-off-by: Hugo Beauzée-Luyssen <hugo@beauzee.fr>

The callback wasn't a forwarding reference.
Thanks to Alexey Sokolov <alexey+vlc@asokolov.org> for reporting.

Doing so would trigger an exception in the Media ctor.