etl/docs/chrono/duration/duration.md

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.