C++ Template Metaprogramming – Is it possible to output the generated code?

by

Nope, in general, it can’t be done. Templates are simply part of the C++ language, they’re not a separate preprocessor, so they don’t generate C++ code.

The usual solution is to sprinkle your code with static asserts and other tests to verify that the right templates get instantiated in the right ways.

Once you start getting lost in your metaprogramming, this simple trick can help you determine which type a template parameter really is:

// given a variable t of an unknown type T
int*** i = t;

When the compiler encounters this, it’ll print out a nice and simple error message, “Can not convert <long, detailed typename> to int***”, allowing you to easily verify that the template parameter T is actually the type you think it should be.

More Related Contents:

  1. Does C++ support compile-time counters?
  2. SFINAE to check for inherited member functions
  3. C++ SFINAE examples?
  4. Can you make custom operators in C++?
  5. Best introduction to C++ template metaprogramming? [closed]
  6. C++: How to require that one template type is derived from the other
  7. How to know if a type is a specialization of std::vector?
  8. How can I expand call to variadic template base classes?
  9. Template Metaprogramming – Difference Between Using Enum Hack and Static Const
  10. C++11 is_same type trait for templates
  11. calculating factorial using template meta-programming
  12. Obtain container type from (its) iterator type in C++ (STL)
  13. Template metaprogram converting type to unique number
  14. Why is partial specialization of a nested class template allowed, while complete isn’t?
  15. overloading friend operator
  16. Variadic template pack expansion
  17. std::function vs template
  18. Advantages of auto in template parameters in C++17
  19. Template template parameters
  20. C++14 Variable Templates: what is their purpose? Any usage example?
  21. How does the compilation of templates work?
  22. C++ template friend operator overloading
  23. For nested templates, when did `>>` become standard C++ (instead of `> >`)?
  24. void_t “can implement concepts”?
  25. How does the linker handle identical template instantiations across translation units?
  26. Using SFINAE to check for global operator
  27. Class template with template class friend, what’s really going on here?
  28. C++ std::map holding ANY type of value
  29. QT : Templated Q_OBJECT class
  30. Will I be able to declare a constexpr lambda inside a template parameter?

Leave a Comment