std::rotl(3)

NAME
std::rotl - std::rotl

Synopsis
   Defined in header <bit>
   template< class T > (since C++20)
   [[nodiscard]] constexpr T rotl( T x, int s ) noexcept;
   Computes the result of bitwise left-rotating the value of x by s positions. This
   operation is also known as a left circular shift.
   Formally, let N be std::numeric_limits<T>::digits, r be s % N.
     * If r is 0, returns x;
     * if r is positive, returns (x << r) | (x >> (N - r));
     * if r is negative, returns std::rotr(x, -r).
   This overload participates in overload resolution only if T is an unsigned integer
   type (that is, unsigned char, unsigned short, unsigned int, unsigned long, unsigned
   long long, or an extended unsigned integer type).

Parameters
   x - value of unsigned integer type
   s - number of positions to shift

Return value
   The result of bitwise left-rotating x by s positions.

Notes
   Feature-test macro Value Std Feature
   __cpp_lib_bitops 201907L (C++20) Bit operations

Example
// Run this code
 #include <bit>
 #include <bitset>
 #include <cstdint>
 #include <iostream>
 int main()
 {
     const std::uint8_t i = 0b00011101;
     std::cout << "i = " << std::bitset<8>(i) << '\n';
     std::cout << "rotl(i,0) = " << std::bitset<8>(std::rotl(i, 0)) << '\n';
     std::cout << "rotl(i,1) = " << std::bitset<8>(std::rotl(i, 1)) << '\n';
     std::cout << "rotl(i,4) = " << std::bitset<8>(std::rotl(i, 4)) << '\n';
     std::cout << "rotl(i,9) = " << std::bitset<8>(std::rotl(i, 9)) << '\n';
     std::cout << "rotl(i,-1) = " << std::bitset<8>(std::rotl(i, -1)) << '\n';
 }

Output:
 i = 00011101
 rotl(i,0) = 00011101
 rotl(i,1) = 00111010
 rotl(i,4) = 11010001
 rotl(i,9) = 00111010
 rotl(i,-1) = 10001110

See also
   rotr computes the result of bitwise right-rotation
   (C++20) (function template)
   operator<<=
   operator>>= performs binary shift left and shift right
   operator<< (public member function of std::bitset<N>)
   operator>>