std::chrono::operator<< (std::chrono::duration)

 

C++

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Technical Specifications

 

Utilities library

Type support (basic types, RTTI, type traits)
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rel_ops::operator!=rel_ops::operator>rel_ops::operator<=rel_ops::operator>=
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three_way_comparablethree_way_comparable_with
strong_ordering weak_ordering partial_ordering common_comparison_category compare_three_way_result compare_three_way	strong_order weak_order partial_order compare_strong_order_fallback compare_weak_order_fallback compare_partial_order_fallback	is_eqis_neqis_ltis_lteqis_gtis_gteq
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pair tuple (C++11) apply (C++17) make_from_tuple (C++17)	optional (C++17) any (C++17) variant (C++17)
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swap
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Date and time utilities

duration (C++11) time_point (C++11) time_of_day (C++20)	clock_time_conversion (C++20) clock_cast (C++20)
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system_clock (C++11) steady_clock (C++11) high_resolution_clock (C++11) is_clock (C++20)	utc_clock (C++20) tai_clock (C++20) gps_clock (C++20) file_clock (C++20) local_t (C++20)
Calendars
day (C++20) month (C++20) year (C++20) weekday (C++20) operator/ (C++20) year_month_day (C++20) year_month_day_last (C++20) year_month_weekday (C++20) year_month_weekday_last (C++20)	weekday_indexed (C++20) weekday_last (C++20) month_day (C++20) month_day_last (C++20) month_weekday (C++20) month_weekday_last (C++20) year_month (C++20)
Time zones
tzdb (C++20) tzdb_list (C++20) get_tzdbget_tzdb_listreload_tzdbremote_version (C++20)(C++20)(C++20)(C++20)	time_zone (C++20) locate_zone (C++20) current_zone (C++20) zoned_time (C++20) link (C++20) leap (C++20)
C-style date and time

 

std::chrono::duration

Member functions
duration::duration
duration::operator=
duration::count
duration::zero
duration::min
duration::max
duration::operator+duration::operator-
duration::operator++duration::operator--
duration::operator+=duration::operator-=duration::operator*=duration::operator/=duration::operator%=
Non-member functions
operator+operator-operator*operator/operator% operator==operator!=operator<operator<=operator>operator>=operator<=> (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20) operator<< (C++20)	duration_cast floor (C++17) ceil (C++17) round (C++17) abs (C++17) operator""h (C++14) operator""min (C++14) operator""s (C++14) operator""ms (C++14) operator""us (C++14) operator""ns (C++14) from_stream (C++20)
Helper classes
common_type treat_as_floating_point duration_values formatter<std::chrono::duration> (C++20)

 

Defined in header <chrono>
template <class CharT, class Traits, class Rep, class Period> std::basic_ostream<CharT, Traits>&     operator<<(std::basic_ostream<CharT, Traits>& os,                const std::chrono::duration<Rep, Period>& d);		(since C++20)

Inserts a textual representation of d into os. The behavior is undefined if CharT is neither char or wchar_t, or if Rep is neither a floating-point type nor a integral type with conversion rank equal to or greater than short.

Behaves as if it forms a std::basic_string<CharT, Traits> str initially consisting of the characters in std::to_string(d.count()) (if CharT is char) or std::to_wstring(d.count()) (if CharT is wchar_t). Appends to str a suffix based on Period::type according to the following table, and inserts str into the stream with os << str;.

Period::type	Suffix
std::atto	as
std::femto	fs
std::pico	ps
std::nano	ns
std::micro	µs (U+00B5)
std::milli	ms
std::centi	cs
std::deci	ds
std::ratio<1>	s
std::deca	das
std::hecto	hs
std::kilo	ks
std::mega	Ms
std::giga	Gs
std::tera	Ts
std::peta	Ps
std::exa	Es
std::ratio<60>	min
std::ratio<3600>	h
std::ratio<86400>	d
None of the above, and Period::type::den == 1	[num]s
None of the above	[num/den]s

For std::micro, if the character µ (U+00B5) cannot be represented in the encoding used for CharT, the suffix "us" is used instead.

For the last two rows of the table, num and den in the suffix are Period::type::num and Period::type::den formatted as a decimal number with no leading zeroes, respectively.

Return value

A reference to the stream, i.e., os.

Notes

d.count() is formatted using the rules of std::to_string/std::to_wstring. In particular, if Rep is a floating-point type, it is always formatted with 6 digits after the decimal point, and the number of significant digits in the resulting string may be zero if d.count() is small.

See also

format (C++20)	stores formatted representation of the arguments in a new string (function template)
std::formatter<std::chrono::duration> (C++20)	specialization of std::formatter that formats a duration according to the provided format (class template specialization)
operator<<operator>>	performs stream input and output on strings (function template)
to_string (C++11)	converts an integral or floating point value to string (function)
to_wstring (C++11)	converts an integral or floating point value to wstring (function)