How is the chronology :: constant_clock rep and period types defined?

Question

chrono::steady_clockIt consists of 4 types of members: rep, period, durationand timepoint.

chrono::steady_clock::durationis chrono::duration<rep,period>. chrono::steady_clock::periodis ratio.

How are types chrono::steady_clock::durationand chrono::steady_clock::period?

For example,

chrono::steady_clock::durationmaybe chrono::duration<int,period>where periodratio<1,1000>

or

chrono::steady_clock::durationmaybe chrono::duration<double,period>where the period is ratio<1,1000000>.

Answer 1

rep period . . , , 100 , std::ratio<100, 1000000000> .

, , .

duration rep period... std::chrono::duration<rep, period>

Answer 2

chrono::steady_clock 4 : rep, period, duration timepoint.

chrono::stead_clock::duration chrono::duration<rep,period>. chrono::steady_clock::period ratio.

.

chrono::stead_clock::duration chrono::steady_clock::period ?

, .

1. rep . , , . de facto , steady_clock::rep 64- .

2. period . VS, libstd++ lib++ steady_clock::period nano.

3. duration rep period: is_same<duration, chrono::duration<rep, period>>{} is true_type. , duration rep period , . .

4. time_point std::chrono::time_point duration. , time_point. , , steady_clock. , , , steady_clock::time_point::clock - steady_clock. - , .