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staticconstexpr size_type npos= size_type(-1); | (since C++17) | |
This is a special value equal to the maximum value representable by the typesize_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.
#include <string_view> constexprboolcontains(std::string_viewconst what,std::string_viewconst where)noexcept{return std::string_view::npos!= where.find(what);} int main(){usingnamespace std::literals; static_assert(contains("water","in a bottle of water")); static_assert(!contains("wine","in a bottle of champagne")); static_assert(""sv.npos=="haystack"sv.find("needle"));}
constexpr size_typenpos[static] | the special valuesize_type(-1), its exact meaning depends on the context[edit] |
