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# nlohmann::json_pointer::empty

    bool empty() const noexcept;

Return whether pointer points to the root document.

## Return value

`true` iff the JSON pointer points to the root document.

## Exception safety

No-throw guarantee: this function never throws exceptions.

## Complexity

Constant.

## Examples

Example

The example shows the result of `empty` for different JSON Pointers.

    #include <iostream>
    #include <nlohmann/json.hpp>

    using json = nlohmann::json;

    int main()
    {
        // different JSON Pointers
        json::json_pointer ptr0;
        json::json_pointer ptr1("");
        json::json_pointer ptr2("/foo");
        json::json_pointer ptr3("/foo/0");

        // call empty()
        std::cout << std::boolalpha
                  << "\"" << ptr0 << "\": " << ptr0.empty() << '\n'
                  << "\"" << ptr1 << "\": " << ptr1.empty() << '\n'
                  << "\"" << ptr2 << "\": " << ptr2.empty() << '\n'
                  << "\"" << ptr3 << "\": " << ptr3.empty() << std::endl;
    }

Output:

    "": true
    "": true
    "/foo": false
    "/foo/0": false

## Version history

Added in version 3.6.0.

Last update: May 1, 2022
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