etl/docs/chrono/chrono-literals.md

title
Chrono literals

{{< callout type="info">}} Header: chrono.h
Since: 20.41.0
Similar to: std::literals::chrono_literals {{< /callout >}}

The ETL Chrono literals are define slightly differently from the STL in that they are user defined, as opposed to language defined.

Example
For STL, the literal to define year 2025 would be 2025y. For ETL, the literal is 2025_y.

By default, the ETL uses the designations of the STL.
As this may clash with other user defined literals, the ETL allows more verbose forms to be used, by defining the macro ETL_USE_VERBOSE_CHRONO_LITERALS.
If enabled, the example of 2025_y would be written as 2025_year.

Duration type	STL like	Verbose
etl::chrono::year	2025_y	2025_year
etl::chrono::day	10_d	10_day
etl::chrono::hours	14_h	14_hours
etl::chrono::minutes	30_min	30_minutes
etl::chrono::seconds	45_s	45_seconds
etl::chrono::milliseconds	500_ms	500_milliseconds
etl::chrono::microseconds	500_us	500_microseconds
etl::chrono::nanoseconds	500_ns	500_nanoseconds

Chrono literals may by accessed by using one of the following namespaces.

using namespace etl::chrono;
using namespace etl::literals;
using namespace etl::chrono_literals;