njlr / ctti

Compile Time Type Information for C++

CTTI

Compile Time Type Information for the C++ programming language.

Background

We know C++ is a statically typed compiled language, but it's disappointing that we cannot even get the name of a C++ type at compile time, having to use RTTI (Run Time Type Information) which introduces a lot of overhead. In fact, that's one of the most feared features of C++, usually disabled in performance dependent scenarios such as videogames programming.

This library aims to provide features similar to RTTI std::type_info at compile-time, currently constexpr type name and a constexpr replacement of std::type_index for indexing maps with types.

#include "ctti/type_id.hpp"

int main()
{
    static_assert(ctti::type_id<int>() != ctti::type_id("hello"), "compile-time type-id comparison");

    std::unordered_map<ctti::type_id_t, std::size_t> sizeof_map;

    sizeof_map[ctti::type_id<int>()] = sizeof(int);
}

Run the examples using Buck

The examples can be run easily using Buck:

buck run examples/
buck run test_package/

Support and current status

This was tested on Visual Studio 2015, GCC 5.2.0, MinGW GCC 5.1, Clang 3.6.2, and cygwin Clang 3.5.2.

Acknowledgments

Thanks a lot to Jonathan "foonathan" Müller, both for the constexpr hash and the idea for the __PRETTY_FUNCTION__ trick.

License

This project is licensed under the MIT license. See LICENSE.md for more details.