[time.clock.system.members]

# 30 Time library [[time]](./#time)

## 30.7 Clocks [[time.clock]](time.clock#system.members)

### 30.7.2 Class system_clock [[time.clock.system]](time.clock.system#members)

#### 30.7.2.2 Members [time.clock.system.members]

[ð](#lib:rep,system_clock)

`using system_clock::rep = unspecified;
`

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/time.tex#L2686)

*Constraints*: system_clock​::​duration​::​min() < system_clock​::​duration​::​zero() is true[.](#1.sentence-1)

[*Note [1](#note-1)*:

This implies that rep is a signed type[.](#1.sentence-2)

â *end note*]

[ð](#lib:to_time_t,system_clock)

`static time_t to_time_t(const time_point& t) noexcept;
`

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/time.tex#L2700)

*Returns*: A time_t object that represents the same point in time as t when both values are restricted to the coarser of the precisions of time_t andtime_point[.](#2.sentence-1)

It is implementation-defined
whether values are rounded or truncated to the required precision[.](#2.sentence-2)

[ð](#lib:from_time_t,system_clock)

`static time_point from_time_t(time_t t) noexcept;
`

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/time.tex#L2716)

*Returns*: A time_point object that represents the same point in time as t when both values are restricted to the coarser of the precisions of time_t andtime_point[.](#3.sentence-1)

It is implementation-defined
whether values are rounded or truncated to the required precision[.](#3.sentence-2)
