Getting started

How to use
Example with Boost.Any
Example with Boost.Variant

boost::typeindex::type_info is a drop-in replacement for std::type_info and boost::typeindex::type_index is a drop-in replacement for std::type_index. Unlike Standard Library versions those classes can work without RTTI.

type_index provides the full set of comparison operators, hashing functions and ostream operators, so it can be used with any container class.

How to use

To start using Boost.TypeIndex:

Replace this:	With the following:	More Info
#include <typeinfo> #include <typeindex>	#include <boost/type_index.hpp>	`more...`
std::type_index	boost::typeindex::type_index	`more...`
typeid(T) typeid(T).name() // not human readable typeid(variable)	boost::typeindex::type_id<T>() boost::typeindex::type_id<T>().pretty_name() // human readable boost::typeindex::type_id_runtime(variable)	`more...` `more...` `more...`
// attempt to save const, volatile, reference typeid(please_save_modifiers<T>)	// cvr = const, volatile, reference boost::typeindex::type_id_with_cvr<T>()	`more...`
// when reference to `std::type_info` is required const std::type_info& v1 = typeid(int); // other cases const std::type_info* v2 = &typeid(int);	const boost::typeindex::type_info& v1 = boost::typeindex::type_id<int>().type_info(); boost::typeindex::type_index v2 = boost::typeindex::type_id<int>();	`more...` `more...`

If you are using type_id_runtime() methods and RTTI is disabled, make sure that classes that are passed to type_id_runtime() are marked with BOOST_TYPE_INDEX_REGISTER_CLASS macro.

Example with Boost.Any

Here is how TypeIndex could be used in boost/any.hpp:

Before	With TypeIndex
#include <typeinfo>	#include <boost/type_index.hpp>
virtual const std::type_info & type() const BOOST_NOEXCEPT { // requires RTTI return typeid(ValueType); }	virtual const boost::typeindex::type_info & type() const BOOST_NOEXCEPT { // now works even with RTTI disabled return boost::typeindex::type_id<ValueType>().type_info(); }

Before

With TypeIndex

#include <typeinfo>

#include <boost/type_index.hpp>

virtual const std::type_info & type() const BOOST_NOEXCEPT
{
    // requires RTTI
    return typeid(ValueType);
}

virtual const boost::typeindex::type_info & type() const BOOST_NOEXCEPT
{
    // now works even with RTTI disabled
    return boost::typeindex::type_id<ValueType>().type_info();
}

Example with Boost.Variant

Here is how TypeIndex could be used in boost/variant/variant.hpp:

Before	With TypeIndex
#if !defined(BOOST_NO_TYPEID) #include <typeinfo> // for typeid, std::type_info #endif // BOOST_NO_TYPEID	#include <boost/type_index.hpp>
#if !defined(BOOST_NO_TYPEID) class reflect : public static_visitor<const std::type_info&> { public: // visitor interfaces template <typename T> const std::type_info& operator()(const T&) const BOOST_NOEXCEPT { return typeid(T); } }; #endif // BOOST_NO_TYPEID	class reflect : public static_visitor<const boost::typeindex::type_info&> { public: // visitor interfaces template <typename T> const boost::typeindex::type_info& operator()(const T&) const BOOST_NOEXCEPT { return boost::typeindex::type_id<T>().type_info(); } };
#if !defined(BOOST_NO_TYPEID) const std::type_info& type() const { detail::variant::reflect visitor; return this->apply_visitor(visitor); } #endif	const boost::typeindex::type_info& type() const { detail::variant::reflect visitor; return this->apply_visitor(visitor); }