std::bit_width
From cppreference.com
| Defined in header <bit>
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| template< class T > constexpr int bit_width( T x ) noexcept; |
(since C++20) | |
If x is not zero, calculates the number of bits needed to store the value x, that is, 1 + floor(log2(x)). If x is zero, returns zero.
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).
Contents |
[edit] Parameters
| x | - | unsigned integer value |
[edit] Return value
Zero if x is zero; otherwise, one plus the base-2 logarithm of x, with any fractional part discarded.
[edit] Notes
This function is equivalent to return std::numeric_limits<T>::digits - std::countl_zero(x);.
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_int_pow2 |
202002L |
(C++20) | Integral power-of-2 operations |