# std::basic_string_view<CharT,Traits>::npos

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< cpp‎ | string‎ | basic string view

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.

### Example

Run this code

    #include <string_view>

    constexpr bool
    contains(std::string_view const what, std::string_view const where) noexcept
    {
        return std::string_view::npos != where.find(what);
    }

    int main()
    {
        using namespace 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"));
    }

### See also

constexpr size_type `npos` [static] | the special value size_type(-1), its exact meaning depends on the context

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