https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116755
--- Comment #10 from Zartaj Majeed <zmajeed at sbcglobal dot net> --- Just tried unsigned duration with system_clock - I guess the requirement for signed Rep is for the default duration - could this have any legitimate use? Or should there be a warning? auto t1 = time_point<system_clock, duration<uint64_t>>{}; println("t1 value {}", t1); ---- t1 value 1970-01-01 00:00:00 ----- This gives the same compile error as before auto d4 = duration<uint64_t>{}; println("d4 value {}", d4);