Return a reference to a rule.

Synopsis

Defined in header <boost/url/grammar/parse.hpp>

template<
    class Rule>
constexpr implementation-defined
ref(
    Rule const& r);

Description

This function returns a rule which references the specified object. This is used to reduce the number of bytes of storage (sizeof) required by a combinator when it stores a copy of the object.

Ownership of the object is not transferred; the caller is responsible for ensuring the lifetime of the object is extended until it is no longer referenced. For best results, ref should only be used with compile-time constants.

Parameters

Convenience header <boost/url/grammar.hpp>