Defined in header <bit> | ||
|---|---|---|
template< class T > constexpr T log2p1(T x) noexcept; | (since C++20) |
If x is not zero, calculates the number of bits needed to store the value x, that is, \(1 + \lfloor log_2(x) \rfloor\)1 + floor(log
2(x)). If x is zero, returns zero.
This overload only participates in overload resolution 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).
Zero if x is zero; otherwise, one plus the base-2 logarithm of x, with any fractional part discarded.
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