When Are Const Reference Values Useful in C ?

Are Const Reference Values of Any Use?

Skepticism regarding the utility of const Foo&&, where Foo represents a class type, is not unfounded. However, contrary to the initial assumption, const reference values do have occasional applications.

The C 0x draft provides a notable example with the following declarations:

template <class T> void ref(const T&&) = delete;
template <class T> void cref(const T&&) = delete;

These overloads prevent ref(T&) and cref(const T&) from binding to rvalues, which would otherwise be possible.

Furthermore, the official C standard N3290, contains a similar set of declarations:

template <class T> void ref(const T&&) = delete;
template <class T> void cref(const T&&) = delete;

These examples demonstrate the usefulness of const reference values in preventing accidental binding to rvalues.

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