C++ Add constraints to a noexcept member function of template class

Question

I have a 3D vector template class and I want to add a normalize member function to it.

Normalizing a vector only makes sense, if they use floating point numbers.

I want to use the c++20 requires syntax with the std::floating_point concept.

template<typename Type>
class vector3 {

  [...]

  vector3& normalize() requires std::floating_point<Type> noexcept;

}

But the compiler (gcc 11.2.0) gives me an error

error: expected ';' at end of member declaration
  242 |   vector3& normalize() requires (std::floating_point<Type>) noexcept;
      |                                                          ^
      |                                                          ;

Answer 1

noexcept is part of declarator, and requires-clause must come after declarator (dcl.decl)

so you need to write

// from @Osyotr in comment
vector3 & normalize() noexcept requires std::is_floating_point_v<Type>; 

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