std::rotl

 

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bit_width (C++20)

Shifting

shl (C++29)

shr (C++29)

Rotating

rotl (C++20)

rotr (C++20)

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countl_zero (C++20)

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countr_zero (C++20)

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bit_reverse (C++29)

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endian (C++20)

 

Defined in header <bit>
template< class T > constexpr T rotl( T x, int s ) noexcept;		(since C++20)

See More

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 and 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).

Parameters

x	-	a value to shift
s	-	the number of positions to shift
Type requirements
T	-	must be an unsigned integer type (that is, unsigned char, unsigned short, unsigned int, unsigned long, unsigned long long, or an extended unsigned integer type) in order to participate in overload resolution.

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()
{
    using bin = std::bitset<8>;
    const std::uint8_t x{0b00011101};
    std::cout << bin(x) << " <- x\n";
    for (const int s : {0, 1, 4, 9, -1})
        std::cout << bin(std::rotl(x, s)) << " <- rotl(x, " << s << ")\n";
}

Output:

00011101 <- x
00011101 <- rotl(x, 0)
00111010 <- rotl(x, 1)
11010001 <- rotl(x, 4)
00111010 <- rotl(x, 9)
10001110 <- rotl(x, -1)

See also

rotr (C++20)	computes the result of bitwise right-rotation (function template)
bit_reverse (C++29)	reverses the bits in an integer (function template)
operator<<=operator>>=operator<<operator>>	performs binary shift left and shift right (public member function of std::bitset<N>)