View source for cpp/chrono/duration/zero

{{cpp/chrono/duration/title|zero}}
{{cpp/chrono/duration/navbar}}
{{dcl begin}}
{{dcl rev multi|until1=c++20|dcl1=
static constexpr duration zero();
|dcl2=
static constexpr duration zero() noexcept;
}}
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Returns a zero-length duration.

If the representation {{tt|rep}} of the duration requires some other implementation to return a zero-length duration, {{lc|std::chrono::duration_values}} can be specialized to return the desired value.

===Parameters===
(none)

===Return value===
Returns {{c|duration(std::chrono::duration_values<rep>::zero())}}.

===Example===
{{example|code=
#include <chrono>
#include <ratio>

template<typename X, typename Y>
using dura = std::chrono::duration<X, Y>;

static_assert
(
    (std::chrono::hours::zero() == std::chrono::nanoseconds::zero()) &&
    (dura<short, std::nano>::zero() == dura<int, std::deci>::zero()) &&
    (dura<short, std::deca>::zero() == dura<long, std::exa>::zero()) &&
    (dura<long, std::atto>::zero().count() == dura<float, std::exa>::zero().count())
);

int main() {}
}}

===See also===
{{dsc begin}}
{{dsc inc|cpp/chrono/duration/dsc min}}
{{dsc inc|cpp/chrono/duration/dsc max}}
{{dsc end}}

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