std::bitset::size (3) Linux Manual Page

std::bitset<N>::size – std::bitset<N>::size

Synopsis

std::size_t size() const; (until C++11)
constexpr std::size_t size() const noexcept; (since C++11)
Returns the number of bits that the bitset can hold.

Parameters

(none)

Return value

number of bits that the bitset can hold, i.e. the template parameter N

See also

      returns the number of bits set to true
count (public member function)