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std::chrono::operator<<(std::chrono::duration)(3) C++ Standard Libary std::chrono::operator<<(std::chrono::duration)(3)


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


Defined in header <chrono>
template <class CharT, class Traits, class Rep, class Period>

std::basic_ostream<CharT, Traits>& (since C++20)
operator<<(std::basic_ostream<CharT, Traits>& os,

const std::chrono::duration<Rep, Period>& d);

Inserts a textual representation of d into os.

Behaves as if it was implemented as

std::basic_ostringstream<CharT, Traits> s;
s << d.count() << units_suffix; // see below
return os << s.str();

In other words, the stream flags, locale, and precision are determined by the
stream, but any padding are determined using the entire output string.

The units_suffix is determined based on Period::type according to the following

Period::type Suffix
std::atto as
std::femto fs
std::pico ps
std::nano ns
std::micro µs (U+00B5) or us, it is implementation-defined which one
is used
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 [num]s
Period::type::den == 1
None of the above [num/den]s

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,

Return value

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

See also

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