How to pass “literal” integers by reference in C++

by

You cannot bind a literal to an lvalue reference to non-const (because modifying the value of a literal is not an operation that makes sense). You can however bind a literal to a reference to const.

So this will compile if you declare fillRect as:

void fillRect(int const& x, int const& y, int const& width, int const& height)

In this case you are passing ints. ints are so cheap to copy that passing by them by reference will probably make the performance of your program worse.

The function fillRect is probably so expensive that the cost of passing its arguments is totally irrelevant in any case. Or maybe it will be inlined, and there will be no cost whatsoever to passing the arguments. These sorts of micro-optimisations are usually not optimisations at all, and should always be guided by the results of profiling (if they are done at all).

More Related Contents:

  1. How to pass objects to functions in C++?
  2. Is it better in C++ to pass by value or pass by constant reference?
  3. Pass by Reference / Value in C++
  4. Passing object by reference to std::thread in C++11
  5. Are there benefits of passing by pointer over passing by reference in C++?
  6. C++ pass an array by reference
  7. Default value to a parameter while passing by reference in C++
  8. Where should I prefer pass-by-reference or pass-by-value?
  9. Is it better in C++ to pass by value or pass by reference-to-const?
  10. Which is more efficient: Return a value vs. Pass by reference?
  11. Function Overloading Based on Value vs. Const Reference
  12. C++ – passing references to std::shared_ptr or boost::shared_ptr
  13. Use of the & operator in C++ function signatures
  14. What is useful about a reference-to-array parameter?
  15. What exactly is the difference between “pass by reference” in C and in C++?
  16. pass by reference and value with pointers [duplicate]
  17. Pass by reference and value in C++
  18. Does C++ pass objects by value or reference?
  19. Performance cost of passing by value vs. by reference or by pointer?
  20. Correct usage of the Eigen::Ref class
  21. C++: Why pass-by-value is generally more efficient than pass-by-reference for built-in (i.e., C-like) types
  22. How is its lifetime of a return value extended to the scope of the calling function when it is bound to a const reference in the calling function?
  23. C++ Passing std::string by reference to function in dll
  24. C++ view types: pass by const& or by value?
  25. What operators do I have to overload to see all operations when passing an object to a function?
  26. STL containers with reference to objects [duplicate]
  27. What are inline namespaces for?
  28. Arrow operator (->) in function heading
  29. How to fix .pch file missing on build?
  30. How serious is the new/delete operator mismatch error?

Leave a Comment