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Updated Examples and Recipes (markdown)

Howard Hinnant
2016-10-24 21:18:13 -04:00
parent bc447f5251
commit 0a0fc0c72f
1 changed files with 1 additions and 16 deletions
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17
Examples-and-Recipes.md

@@ -743,22 +743,7 @@ Assuming the birthdate is exactly synchronized with TAI (offset by the timezone)
auto birthday = to_tai_time(make_zoned(zone,
local_days{apr/24/1954} + 10h + 3min - 10s).get_sys_time());
We have to subtract 10s manually because we want the birthday to be `1954-04-24 18:03:00 TAI` and without that 10s subtraction we have UTC modeled back to 1954 instead of modeling TAI in 1954.
Another way to do this would be to "reinterpret_cast" the `sys_time` to `tai_time`. This would relieve us from having to know about the 10s constant. This is done with the following syntax:
auto birthday = tai_seconds{make_zoned(zone,
local_days{apr/24/1954} + 10h + 3min).get_sys_time().time_since_epoch()};
Either way, the result is the same. This line:
std::cout << "born : " << birthday << " TAI \n";
will output:
born : 1942-04-24 18:03:00 TAI
Then we add the 2Gs in `tai_time` and convert that result back to `sys_time`, and then to a `zoned_time`:
We have to subtract 10s manually because we want the birthday to be `1954-04-24 18:03:00 TAI` and without that 10s subtraction we have UTC modeled back to 1954 instead of modeling TAI in 1954. Then we add the 2Gs in `tai_time` and convert that result back to `sys_time`, and then to a `zoned_time`:
auto Day2Gs = make_zoned(zone, to_sys_time(birthday + 2'000'000'000s));