std::basic_string_view<CharT,Traits>::npos (3) - Linux Manuals
std::basic_string_view<CharT,Traits>::npos: std::basic_string_view<CharT,Traits>::npos
NAME
std::basic_string_view<CharT,Traits>::npos - std::basic_string_view<CharT,Traits>::npos
Synopsis
static constexpr size_type npos = size_type(-1); (since C++17)
This is a special value equal to the maximum value representable by the type size_type. The exact meaning depends on context, but it is generally used either as end of view indicator by the functions that expect a view index or as the error indicator by the functions that return a view index.