33 Concurrency support library [thread]

33.2 Requirements [thread.req]

33.2.1 Template parameter names [thread.req.paramname]

Throughout this Clause, the names of template parameters are used to express type requirements.
If a template parameter is named Predicate, operator() applied to the template argument shall return a value that is convertible to bool.
If a template parameter is named Clock, the corresponding template argument shall be a type C that meets the Cpp17Clock requirements ([time.clock.req]); the program is ill-formed if is_­clock_­v<C> is false.