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Standard library header <bit> (C++20)

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This header is part of the numeric library.

Types

(C++20)
indicates the endianness of scalar types
(enum) [edit]

Functions

(C++20)
reinterpret the object representation of one type as that of another
(function template) [edit]
(C++23)
reverses the bytes in the given integer value
(function template) [edit]
checks if a number is an integral power of 2
(function template) [edit]
(C++20)
finds the smallest integral power of two not less than the given value
(function template) [edit]
(C++20)
finds the largest integral power of two not greater than the given value
(function template) [edit]
(C++20)
finds the smallest number of bits needed to represent the given value
(function template) [edit]
(C++20)
computes the result of bitwise left-rotation
(function template) [edit]
(C++20)
computes the result of bitwise right-rotation
(function template) [edit]
counts the number of consecutive 0 bits, starting from the most significant bit
(function template) [edit]
counts the number of consecutive 1 bits, starting from the most significant bit
(function template) [edit]
counts the number of consecutive 0 bits, starting from the least significant bit
(function template) [edit]
counts the number of consecutive 1 bits, starting from the least significant bit
(function template) [edit]
(C++20)
counts the number of 1 bits in an unsigned integer
(function template) [edit]

[edit] Synopsis

namespace std {
  // bit_cast
  template<class To, class From>
    constexpr To bit_cast(const From& from) noexcept;
 
  // byteswap
  template <class T>
    constexpr T byteswap(T value) noexcept;
 
  // integral powers of 2
  template<class T>
    constexpr bool has_single_bit(T x) noexcept;
  template<class T>
    constexpr T bit_ceil(T x);
  template<class T>
    constexpr T bit_floor(T x) noexcept;
  template<class T>
    constexpr int bit_width(T x) noexcept;
 
  // rotating
  template<class T>
    [[nodiscard]] constexpr T rotl(T x, int s) noexcept;
  template<class T>
    [[nodiscard]] constexpr T rotr(T x, int s) noexcept;
 
  // counting
  template<class T>
    constexpr int countl_zero(T x) noexcept;
  template<class T>
    constexpr int countl_one(T x) noexcept;
  template<class T>
    constexpr int countr_zero(T x) noexcept;
  template<class T>
    constexpr int countr_one(T x) noexcept;
  template<class T>
    constexpr int popcount(T x) noexcept;
 
  // endian
  enum class endian {
    little = /* see description */,
    big    = /* see description */,
    native = /* see description */
  };
}