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

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< cpp‎ | string‎ | basic string view

constexpr bool empty() const noexcept; |  | (since C++17) (until C++20)
[[nodiscard]] constexpr bool empty() const noexcept; |  | (since C++20)

Checks if the view has no characters, i.e. whether size() `==` ​0​.

### Parameters

(none)

### Return value

true if the view is empty, false otherwise.

### Complexity

Constant.

### Example

Run this code

    #include <iostream>
    #include <string_view>

    // Print a string surrounded by single quotes, its
    // length and whether it is considered empty.
    void check_string(std::string_view ref)
    {
        std::cout << std::boolalpha
                  << "'" << ref << "' has " << ref.size()
                  << " character(s); emptiness: " << ref.empty() << '\n';
    }

    int main(int argc, char **argv)
    {
        // An empty string
        check_string("");

        // Almost always not empty: argv[0]
        if (argc > 0)
            check_string(argv[0]);
    }

Possible output:

    '' has 0 character(s); emptiness: true
    './a.out' has 7 character(s); emptiness: false

### See also

size length (C++17) | returns the number of characters (public member function)
max_size (C++17) | returns the maximum number of characters (public member function)
size ssize (C++17)(C++20) | returns the size of a container or array (function template)
empty (C++17) | checks whether the container is empty (function template)
empty | checks whether the string is empty (public member function of `std::basic_string<CharT,Traits,Allocator>`)

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