ref_unwrapped

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##### ref_unwrapped

Syntax | Code
--- | ---
Pipe | `rng | boost::adaptors::ref_unwrapped`
Function | `boost::adaptors::ref_unwrap(rng)`

This adaptor produces a range than applies `.get()` on all values in the range. It is useful for iterating ranges of `std::reference_wrapper` values or values using similar semantics.

The adaptor is C++11 (and above) only.

- Precondition: The `value_type` of the range has a `.get() const`.
- Postcondition: For all elements `x` in the returned range, `x` is the result of `y.get()` where `y` is the corresponding element in the original range.
- Range Category: Single Pass Range
- Range Return Type: `boost::unwrap_ref_range<decltype(rng)>`
- Returned Range Category: The range category of `rng`.

###### ref_unwrapped example

    #include <boost/range/adaptor/ref_unwrapped.hpp>
    #include <iostream>
    #include <vector>

    struct example
    {
      int value;
    };

    int main(int argc, const char* argv[])
    {
        using boost::adaptors::ref_unwrapped;

        example one{1};
        example two{2};
        example three{3};

        std::vector<std::reference_wrapper<example> > input{one, two, three};

        for (auto&& entry : input | ref_unwrapped)
        {
          std::cout << entry.value;
        }

        return 0;
    }

This would produce the output `123`.