27 Time library [time]

27.7 Clocks [time.clock]

27.7.1 Class system_­clock [time.clock.system]

27.7.1.3 Non-member functions [time.clock.system.nonmembers]

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template<class charT, class traits, class Duration> basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>& os, const sys_time<Duration>& tp);
1
#
Constraints: treat_­as_­floating_­point_­v<typename Duration​::​rep> is false, and Duration{1} < days{1} is true.
2
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Effects: Equivalent to: 
auto const dp = floor<days>(tp);
return os << format(os.getloc(), STATICALLY-WIDEN<charT>("{} {}"),
                    year_month_day{dp}, hh_mm_ss{tp-dp});
3
#
[ Example
: 
cout << sys_seconds{0s} << '\n';                // 1970-01-01 00:00:00
cout << sys_seconds{946'684'800s} << '\n';      // 2000-01-01 00:00:00
cout << sys_seconds{946'688'523s} << '\n';      // 2000-01-01 01:02:03
— end example
 ]
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template<class charT, class traits> basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>& os, const sys_days& dp);
4
#
Effects: os << year_­month_­day{dp}.
5
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Returns: os.
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template<class charT, class traits, class Duration, class Alloc = allocator<charT>> basic_istream<charT, traits>& from_stream(basic_istream<charT, traits>& is, const charT* fmt, sys_time<Duration>& tp, basic_string<charT, traits, Alloc>* abbrev = nullptr, minutes* offset = nullptr);
6
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Effects: Attempts to parse the input stream is into the sys_­time tp using the format flags given in the NTCTS fmt as specified in [time.parse].
If the parse fails to decode a valid date, is.setstate(ios_­base​::​failbit) is called and tp is not modified.
If %Z is used and successfully parsed, that value will be assigned to *abbrev if abbrev is non-null.
If %z (or a modified variant) is used and successfully parsed, that value will be assigned to *offset if offset is non-null.
Additionally, the parsed offset will be subtracted from the successfully parsed timestamp prior to assigning that difference to tp.
7
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Returns: is.