[time.cal.month.members]

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

## 30.8 The civil calendar [[time.cal]](time.cal#month.members)

### 30.8.4 Class month [[time.cal.month]](time.cal.month#members)

#### 30.8.4.2 Member functions [time.cal.month.members]

[ð](#lib:month,constructor)

`constexpr explicit month(unsigned m) noexcept;
`

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/time.tex#L4283)

*Effects*: Initializes m_ with m[.](#1.sentence-1)

The value held is unspecified if m is not in the range [0, 255][.](#1.sentence-2)

[ð](#lib:operator++,month)

`constexpr month& operator++() noexcept;
`

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/time.tex#L4295)

*Effects*: *this += months{1}[.](#2.sentence-1)

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/time.tex#L4299)

*Returns*: *this[.](#3.sentence-1)

[ð](#lib:operator++,month_)

`constexpr month operator++(int) noexcept;
`

[4](#4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/time.tex#L4310)

*Effects*: ++(*this)[.](#4.sentence-1)

[5](#5)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/time.tex#L4314)

*Returns*: A copy of *this as it existed on entry to this member function[.](#5.sentence-1)

[ð](#lib:operator--,month)

`constexpr month& operator--() noexcept;
`

[6](#6)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/time.tex#L4325)

*Effects*: *this -= months{1}[.](#6.sentence-1)

[7](#7)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/time.tex#L4329)

*Returns*: *this[.](#7.sentence-1)

[ð](#lib:operator--,month_)

`constexpr month operator--(int) noexcept;
`

[8](#8)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/time.tex#L4340)

*Effects*: --(*this)[.](#8.sentence-1)

[9](#9)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/time.tex#L4344)

*Returns*: A copy of *this as it existed on entry to this member function[.](#9.sentence-1)

[ð](#lib:operator+=,month)

`constexpr month& operator+=(const months& m) noexcept;
`

[10](#10)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/time.tex#L4355)

*Effects*: *this = *this + m[.](#10.sentence-1)

[11](#11)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/time.tex#L4359)

*Returns*: *this[.](#11.sentence-1)

[ð](#lib:operator-=,month)

`constexpr month& operator-=(const months& m) noexcept;
`

[12](#12)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/time.tex#L4370)

*Effects*: *this = *this - m[.](#12.sentence-1)

[13](#13)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/time.tex#L4374)

*Returns*: *this[.](#13.sentence-1)

[ð](#lib:operator_unsigned,month)

`constexpr explicit operator unsigned() const noexcept;
`

[14](#14)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/time.tex#L4385)

*Returns*: m_[.](#14.sentence-1)

[ð](#lib:ok,month)

`constexpr bool ok() const noexcept;
`

[15](#15)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/time.tex#L4396)

*Returns*: 1 <= m_ && m_ <= 12[.](#15.sentence-1)
