etl/docs/chrono/duration/duration.md
John Wellbelove 4a88884b39
Issue/add hugo support for documentation (#1449)
* Add ranges

* Initial Hugo setup

* Work in progress

* Added selection for local or remote site

* Updated to 'light' theme

* Changed to using Hextra Hugo theme

* Changed to using Hextra Hugo theme

* Changed to Hextra Hugo theme

* Change to Hextra Hugo theme

* Updated Hugo setup.

* Updated Hugo setup.

# Conflicts:
#	docs/releases/_index.md

* Work in progress

* Added new fonts

Added new documentation

* Latest documentation updates

* Latest documentation updates

# Conflicts:
#	docs/containers/array.md
#	docs/containers/array_view.md
#	docs/containers/array_wrapper.md
#	docs/containers/bip_buffer_spsc_atomic.md
#	docs/containers/bitset.md
#	docs/containers/indirect_vector.md
#	docs/containers/vector.md
#	docs/getting-started/compilers.md

* Added bloom_filter markdown doc

* Added more documentation

Updated CSS for light and dark modes

* Fixed some menus

Added mode documentation files

* Updated CSS rules

Added badges to home page
Added uniqur_ptr + pool tutorial

* Fixed formatting on the home page markdown

Modified light amd dark code formatting

* Updated unique_ptr-with-pool

* Added container and shared message tutorials

* Updates to documentation

* Added const_multimap

* Updated source-formatting.md

* Added initial raw text files form Web site editor

* Innore coverage build directory

* Exported raw text documentation files from the web site editor

* Hugo updates

* Added Hugo intalation and markdown descriptions

* More addition to the documentation

* Added closure.md and updates to delegate.md

* Added format.md

* Added documentation for etl::delegate_observable, etl::function, Base64 codec

* Added io_port documentation

* Added basic_format_spec

* Added documentation for string_stream and string utilities.

* Added more documentation

Updated the documentation CSS

* Added documentation for clocks, day, duration

* Added more documentation for chrono classes

Updated callouts

* More chrono documentation

* Completed chrono documentation

* Maths functions documentation

* Completed maths documentation

* Completed maths documentation

* Completed maths documentation

* Completed maths documentation

* Added multiple documentation files

* Added iterator.md

* Added debug_count.md and versions.md

* Added debug_count.md and versions.md

* Added more documentation

* More documentation

* Added some design pattern documentation

Modified some of the layout files
Modified the About documentation

* Converted more documentation pages

Modified the site CSS

* Added more documentation

Moced some documentation files to new directories

* Added more documentation

Tweaks to CSS

* Added callback_timer_deferred_locked documentation

* Added callback_timer_locked documentation

* More documentation updates

* More documentation updates

* More documentation updates

* New documentation files.

Harmonised file name format

* New documentation files.

* Multiple document updates

* Multiple document updates

* Final conversion of web pages

* Updates before PR

* Updates before PR

* Updates before PR

# Conflicts:
#	docs/blog/_index.md

* Final pre PR updates

* Updates to message framework documentation

* Renamed directory

* Fix spelling

* Added author and date to blog files

Moved documentation files merged from development

* Fixed 'Description' typo

* Fix typos

# Conflicts:
#	docs/IO/io_port.md
#	docs/containers/sets/const-multiset.md
#	docs/containers/sets/const-set.md
#	docs/maths/correlation.md
#	docs/maths/gamma.md

* Renamed two files to lower case

* Minor renaming

* Added author and date

* Updated callout on bresenham_line.md

Added support for showing the ETL version on the documentation first page, by copying the version.txt file as a hugo asset.
Updated the Python 'update_release.py' to copy 'version.txt'

* Replace space in filename with hyphen.

Added more information to hugo-commands.md

* Replace space in filename with hyphen.

Added more information to hugo-commands.md

# Conflicts:
#	docs/getting-started/view-the-docs-locally/hugo-commands.md

* Added a link to pseudo_moving_average.md

* Updated title pages for groups

* Fixed missing 404 for non-existent pages

* Fixed coordinate variable names in the 'Calculating the intersection' example

---------

Co-authored-by: Roland Reichwein <Roland.Reichwein@bmw.de>
Co-authored-by: John Wellbelove <john.wellbelove@etlcpp.com>
Co-authored-by: John Wellbelove <john.wellbelove@etlcpp.co.uk>
2026-06-06 13:12:44 +01:00

11 KiB

title
duration

{{< callout type="info">}} Header: chrono.h
Since: TBC
Similar to: std::chrono::duration
Similar to: std::chrono::duration_values {{< /callout >}}

Templates representing a time interval.

duration_values

template <typename TRep>
struct duration_values
ETL_NODISCARD static ETL_CONSTEXPR TRep zero() ETL_NOEXCEPT

Return
TRep(0)


ETL_NODISCARD static ETL_CONSTEXPR14 TRep min() ETL_NOEXCEPT

Return
etl::numeric_limits<TRep>::min()


ETL_NODISCARD static ETL_CONSTEXPR14 TRep max() ETL_NOEXCEPT

Returns
etl::numeric_limits<TRep>::max()

duration

template <typename TRep, typename TPeriod = etl::ratio<1>>
class duration
using rep = TRep
using period = typename TPeriod::type;

Construction

ETL_CONSTEXPR 
duration() 
ETL_NOEXCEPT

Description
Default constructor.


ETL_CONSTEXPR14
duration(const etl::chrono::duration<TRep, TPeriod>& other) 
ETL_NOEXCEPT

template <typename TRep2>
ETL_CONSTEXPR14 
explicit duration(const TRep2& value) 
ETL_NOEXCEPT

template <typename TRep2, typename TPeriod2>
ETL_CONSTEXPR14 
duration(const etl::chrono::duration<TRep2, TPeriod2>& other) 
ETL_NOEXCEPT

Description
Construct from another duration type.
Enabled if etl::ratio_divide<TPeriod2, TPeriod>::den == 1

Tests

ETL_NODISCARD
ETL_CONSTEXPR14 
int compare(const time_point& other) const 
ETL_NOEXCEPT

Description
Compare day with another.
if time_point < other, returns -1
else if time_point > other, returns 1
else returns 0

Assignment

ETL_CONSTEXPR14 
etl::chrono::duration<TRep, TPeriod> operator =(const etl::chrono::duration<TRep, TPeriod>& other) ETL_NOEXCEPT

template <typename TRep2, typename TPeriod2>
ETL_CONSTEXPR14 
etl::chrono::duration<TRep, TPeriod> operator =(const etl::chrono::duration<TRep2, TPeriod2>& other) ETL_NOEXCEPT

Convertion

ETL_CONSTEXPR14 
TRep count() const 
ETL_NOEXCEPT

Return
The duration count as a numeric.


ETL_CONSTEXPR14 
etl::common_type_t<duration> operator +() const 
ETL_NOEXCEPT

Description
Implements unary plus.


ETL_CONSTEXPR14 
etl::common_type_t<duration> operator -() const 
ETL_NOEXCEPT

Description
Implements unary minus.


ETL_NODISCARD
ETL_CONSTEXPR14 
etl::chrono::duration<TRep, TPeriod> absolute() const 
ETL_NOEXCEPT

Return
The absolute value of the duration.


Constants

ETL_NODISCARD
static ETL_CONSTEXPR14 etl::chrono::duration<TRep, TPeriod> zero()  
ETL_NOEXCEPT

Return
The duration zero value.


ETL_NODISCARD
static ETL_CONSTEXPR14 etl::chrono::duration<TRep, TPeriod> min()
ETL_NOEXCEPT

Return
The minimum duration value.


ETL_NODISCARD
static ETL_CONSTEXPR14 etl::chrono::duration<TRep, TPeriod> max()
ETL_NOEXCEPT
---
**Return**  
The maximum duration value.

## Increment/decrement
```cpp
ETL_CONSTEXPR14 
duration& operator ++()
ETL_NOEXCEPT

Description
Pre-increments the duration count.


ETL_CONSTEXPR14 
duration operator ++(int)
ETL_NOEXCEPT

Description
Post-increments the duration count.


ETL_CONSTEXPR14 
duration& operator --()
ETL_NOEXCEPT

Description
Pre-decrements the duration count.


ETL_CONSTEXPR14 
duration operator --(int)
ETL_NOEXCEPT

Description
Post-decrements the duration count.

Mathematical operators

ETL_CONSTEXPR14 
duration& operator +=(const duration<TRep, TPeriod>& d)
ETL_NOEXCEPT

Description
Adds duration d to this duration.


ETL_CONSTEXPR14 
duration& operator -=(const duration<TRep, TPeriod>& d)
ETL_NOEXCEPT

Description
Subtracts duration d to this duration.


ETL_CONSTEXPR14 
duration& operator *=(const TRep& r) 
ETL_NOEXCEPT

Description
Multiplies this duration by r.


ETL_CONSTEXPR14 
duration& operator /=(const TRep& r)
ETL_NOEXCEPT

Description
Divides this duration by r.


ETL_CONSTEXPR14 
duration& operator %=(const TRep& r)
ETL_NOEXCEPT

Description
Sets this duration to the modulus of r.


ETL_CONSTEXPR14 
duration& operator %=(const duration<TRep, TPeriod>& d)
ETL_NOEXCEPT

Description
Sets this duration to the modulus of duration d.

Comparison

template <typename TRep2, typename TPeriod2>
ETL_CONSTEXPR14 
int compare(const duration<TRep2, TPeriod2>& other) const
ETL_NOEXCEPT

Description
Compare duration with another.
If duration < other, returns -1
else if duration > other, returns 1
else returns 0

Non-member mathematical operators

template <typename TRep1, typename TPeriod1, typename TRep2, typename TPeriod2>
ETL_CONSTEXPR14 
etl::common_type_t<etl::chrono::duration<TRep1, TPeriod1>, 
                   etl::chrono::duration<TRep2, TPeriod2>>
operator +(const etl::chrono::duration<TRep1, TPeriod1>& lhs, 
           const etl::chrono::duration<TRep2, TPeriod2>& rhs)
ETL_NOEXCEPT

Description
Operator +


template <typename TRep1, typename TPeriod1, typename TRep2, typename TPeriod2>
ETL_CONSTEXPR14
etl::common_type_t<etl::chrono::duration<TRep1, TPeriod1>, 
                   etl::chrono::duration<TRep2, TPeriod2> >::type 
operator -(const etl::chrono::duration<TRep1, TPeriod1>& lhs, 
           const etl::chrono::duration<TRep2, TPeriod2>& rhs)
ETL_NOEXCEPT

Description
Operator -


template <typename TRep1, typename TPeriod1, typename TRep2>
ETL_CONSTEXPR14
etl::chrono::duration<etl::common_type_t<TRep1, TRep2>, TPeriod1>>
operator *(const etl::chrono::duration<TRep1, TPeriod1>& lhs, 
           const TRep2& rhs)
ETL_NOEXCEPT

Description
Operator *
Enabled if TRep2 is not a specialization of etl::chrono::duration.


template <typename TRep1, typename TRep2, typename TPeriod2>
ETL_CONSTEXPR14 
etl::chrono::duration<etl::common_type_t<TRep1, TRep2>, TPeriod2>
operator *(const TRep1& lhs, 
           const etl::chrono::duration<TRep2, TPeriod2>& rhs)
ETL_NOEXCEPT

Description
Operator *


template <typename TRep1, typename TPeriod1, typename TRep2>
ETL_CONSTEXPR14 
etl::common_type_t<TRep1, TRep2>, TPeriod1>
operator /(const etl::chrono::duration<TRep1, TPeriod1>& lhs, 
           const TRep2& rhs)
ETL_NOEXCEPT

Description
Operator /
Enabled if TRep2 is not a specialization of etl::chrono::duration.


template <typename TRep1, typename TPeriod1, typename TRep2, typename TPeriod2>
ETL_CONSTEXPR14
etl::common_type_t<TRep1, TRep2>
operator /(const etl::chrono::duration<TRep1, TPeriod1>& lhs, 
           const etl::chrono::duration<TRep2, TPeriod2>& rhs)
ETL_NOEXCEPT

Description
Operator /


template <typename TRep1, typename TPeriod1, typename TRep2>
ETL_CONSTEXPR14 
etl::chrono::duration<etl::common_type_t<TRep1, TRep2>, TPeriod1>
operator %(const etl::chrono::duration<TRep1, TPeriod1>& lhs, 
           const TRep2& rhs)
ETL_NOEXCEPT

Description
Operator %


```cpp
template <typename TRep1, typename TPeriod1, typename TRep2, typename TPeriod2>
ETL_CONSTEXPR14 
etl::common_type_t<etl::chrono::duration<TRep1, TPeriod1>, 
                   etl::chrono::duration<TRep2, TPeriod2>>
operator %(const etl::chrono::duration<TRep1, TPeriod1>& lhs, 
           const etl::chrono::duration<TRep2, TPeriod2>& rhs)
ETL_NOEXCEPT

Description
Operator %

Non-member comparison operators

template <typename TRep1, typename TPeriod1, typename TRep2, typename TPeriod2>
ETL_CONSTEXPR14
bool operator ==(const etl::chrono::duration<TRep1, TPeriod1>& lhs, 
                 const etl::chrono::duration<TRep2, TPeriod2>& rhs) 
ETL_NOEXCEPT

Description
Checks for equality.


template <typename TRep1, typename TPeriod1, typename TRep2, typename TPeriod2>
ETL_CONSTEXPR14 
bool operator !=(const etl::chrono::duration<TRep1, TPeriod1>& lhs, 
                 const etl::chrono::duration<TRep2, TPeriod2>& rhs) 
ETL_NOEXCEPT

Description
Checks for inequality.


template <typename TRep1, typename TPeriod1, typename TRep2, typename TPeriod2>
ETL_CONSTEXPR14 
bool operator <(const etl::chrono::duration<TRep1, TPeriod1>& lhs, 
                const etl::chrono::duration<TRep2, TPeriod2>& rhs) 
ETL_NOEXCEPT

Description
Checks for less-than.


template <typename TRep1, typename TPeriod1, typename TRep2, typename TPeriod2>
ETL_CONSTEXPR14 
bool operator <=(const etl::chrono::duration<TRep1, TPeriod1>& lhs, 
                 const etl::chrono::duration<TRep2, TPeriod2>& rhs) 
ETL_NOEXCEPT

Description
Checks for less-than-or-equal.


template <typename TRep1, typename TPeriod1, typename TRep2, typename TPeriod2>
ETL_CONSTEXPR14
bool operator >(const etl::chrono::duration<TRep1, TPeriod1>& lhs, 
                const etl::chrono::duration<TRep2, TPeriod2>& rhs) 
ETL_NOEXCEPT

Description
Checks for greater-than.


template <typename TRep1, typename TPeriod1, typename TRep2, typename TPeriod2>
ETL_CONSTEXPR14
bool operator >=(const etl::chrono::duration<TRep1, TPeriod1>& lhs, 
                 const etl::chrono::duration<TRep2, TPeriod2>& rhs) 
ETL_NOEXCEPT

Description
Checks for greater-than-or-equal.


template <typename TRep1, typename TPeriod1, typename TRep2, typename TPeriod2>
[[nodiscard]] 
constexpr 
auto operator <=>(const etl::chrono::duration<TRep1, TPeriod1>& lhs, 
                  const etl::chrono::duration<TRep2, TPeriod2>& rhs) 
noexcept

Description
Spaceship operator.
C++20

common_type

template <typename TRep1, typename TPeriod1, typename TRep2, typename TPeriod2>
struct common_type<etl::chrono::duration<TRep1, TPeriod1>, etl::chrono::duration<TRep2, TPeriod2>>

Description
etl::common_type specialisation for etl::duration.

Hash

template <typename TRep, typename TPeriod>
struct hash<etl::chrono::duration<TRep, TPeriod>>

Pre-defined duration types

etl::chrono::years
etl::chrono::months
etl::chrono::weeks
etl::chrono::days
etl::chrono::hours
etl::chrono::minutes
etl::chrono::seconds
etl::chrono::milliseconds
etl::chrono::microseconds
etl::chrono::nanoseconds

duration_cast

template <typename TToDuration, typename TRep, typename TPeriod>
ETL_CONSTEXPR14 
TToDuration duration_cast(const etl::chrono::duration<TRep, TPeriod>& d)
ETL_NOEXCEPT

Description
Converts from one duration type to another.