---
name: "std::numbers"
section: "3cxx"
platform: "linux"
package: "libstdc++-12-doc"
version: "12.4.0-5"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/std::numbers"
---

# std::numbers(3cxx)

Namespace for mathematical constants.

## NAME

std::numbers - Namespace for mathematical constants.

## SYNOPSIS

### Variables

constexpr double **e**\
 template\<**typename** \_Tp \> constexpr \_Tp **e\_v**\
 e  constexpr double **egamma**\
 template\<**typename** \_Tp \> constexpr \_Tp **egamma\_v**\
 The Euler-Mascheroni constant.  constexpr double **inv\_pi**\
 template\<**typename** \_Tp \> constexpr \_Tp **inv\_pi\_v**\
 1/pi  constexpr double **inv\_sqrt3**\
 template\<**typename** \_Tp \> constexpr \_Tp **inv\_sqrt3\_v**\
 1/[sqrt(3)](/sqrt/3.md)  constexpr double **inv\_sqrtpi**\
 template\<**typename** \_Tp \> constexpr \_Tp **inv\_sqrtpi\_v**\
 1/sqrt(pi)  constexpr double **ln10**\
 template\<**typename** \_Tp \> constexpr \_Tp **ln10\_v**\
 log\_e 10  constexpr double **ln2**\
 template\<**typename** \_Tp \> constexpr \_Tp **ln2\_v**\
 log\_e 2  constexpr double **log10e**\
 template\<**typename** \_Tp \> constexpr \_Tp **log10e\_v**\
 log\_10 e  constexpr double **log2e**\
 template\<**typename** \_Tp \> constexpr \_Tp **log2e\_v**\
 log\_2 e  constexpr double **phi**\
 template\<**typename** \_Tp \> constexpr \_Tp **phi\_v**\
 The golden ratio, (1+sqrt(5))/2.  constexpr double **pi**\
 template\<**typename** \_Tp \> constexpr \_Tp **pi\_v**\
 pi  constexpr double **sqrt2**\
 template\<**typename** \_Tp \> constexpr \_Tp **sqrt2\_v**\
 sqrt(2)  constexpr double **sqrt3**\
 template\<**typename** \_Tp \> constexpr \_Tp **sqrt3\_v**\
 [sqrt(3)](/sqrt/3.md)

## Detailed Description

Namespace for mathematical constants.

## Variable Documentation

### template\<typename \_Tp \> constexpr \_Tp std::numbers::e\_v` [inline]`, ` [constexpr]`

e

### template\<typename \_Tp \> constexpr \_Tp std::numbers::egamma\_v` [inline]`, ` [constexpr]`

The Euler-Mascheroni constant.

### template\<typename \_Tp \> constexpr \_Tp std::numbers::inv\_pi\_v` [inline]`, ` [constexpr]`

1/pi

### template\<typename \_Tp \> constexpr \_Tp std::numbers::inv\_sqrt3\_v` [inline]`, ` [constexpr]`

1/[sqrt(3)](/sqrt/3.md)

### template\<typename \_Tp \> constexpr \_Tp std::numbers::inv\_sqrtpi\_v` [inline]`, ` [constexpr]`

1/sqrt(pi)

### template\<typename \_Tp \> constexpr \_Tp std::numbers::ln10\_v` [inline]`, ` [constexpr]`

log\_e 10

### template\<typename \_Tp \> constexpr \_Tp std::numbers::ln2\_v` [inline]`, ` [constexpr]`

log\_e 2

### template\<typename \_Tp \> constexpr \_Tp std::numbers::log10e\_v` [inline]`, ` [constexpr]`

log\_10 e

### template\<typename \_Tp \> constexpr \_Tp std::numbers::log2e\_v` [inline]`, ` [constexpr]`

log\_2 e

### template\<typename \_Tp \> constexpr \_Tp std::numbers::phi\_v` [inline]`, ` [constexpr]`

The golden ratio, (1+sqrt(5))/2.

### template\<typename \_Tp \> constexpr \_Tp std::numbers::pi\_v` [inline]`, ` [constexpr]`

pi

### template\<typename \_Tp \> constexpr \_Tp std::numbers::sqrt2\_v` [inline]`, ` [constexpr]`

sqrt(2)

### template\<typename \_Tp \> constexpr \_Tp std::numbers::sqrt3\_v` [inline]`, ` [constexpr]`

[sqrt(3)](/sqrt/3.md)

## Author

Generated automatically by Doxygen for libstdc++ from the source code.