Boost C++ Libraries

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This is the documentation for a snapshot of the develop branch, built from commit 549cd0dc90.
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nvp

Overview
Examples
Reference
History

The header <boost/core/nvp.hpp> provides the class template boost::nvp that pairs a name (const char*) with the address of a value (T*). It is the new implementation of the NVP type previously provided by the Boost Serialization library. This type now lives in the Core library so that other Boost libraries can support named value serialization without taking a dependency on the Serialization library.

The following snippet shows use in a member serialize function:

template<class A>
void serialize(A& archive, unsigned)
{
    archive & boost::make_nvp("x", x_) & boost::make_nvp("y", y_);
}
namespace boost {

template<class T>
class nvp {
public:
    nvp(const char* name, T& value) noexcept;

    const char* name() const noexcept;

    T& value() const noexcept;

    const T& const_value() const noexcept;
};

template<class T>
const nvp<T> make_nvp(const char* name, T& value) noexcept;

} /* boost */

#define BOOST_NVP(object) see below

nvp(const char* name, T& value) noexcept;

Initializes the stored name pointer with name and the value pointer with addressof(value).

const char* name() const noexcept;

Returns a pointer to the name.

T& value() const noexcept;

Returns a reference to the value.

const T& const_value() const noexcept;

Returns a reference to the value.

template<class T> const nvp<T> make_nvp(const char* name, T& value) noexcept;

Returns nvp<T>(name, value).

#define BOOST_NVP(object) see below

Expands to boost::make_nvp(BOOST_STRINGIZE(object), object).

Robert Ramey originally implemented NVP in the Serialization library. Glen Fernandes implemented this new (but compatible) version in the Core library.


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