Returning const reference to local variable from a function

by

1. Is getA1() implementation correct ? I feel it is incorrect as it is returning address of local variable or temporary.

The only version of getAx() that is correct in your program is getA3(). Both of the others have undefined behaviour no matter how you use them later.

2. Which of the statements in main ( 1,2,3) will lead to undefined behavior ?

In one sense none of them. For 1 and 2 the undefined behaviour is as a result of the bodies of the functions. For the last line, newA3 should be a compile error as you cannot bind a temporary to a non const reference.

3. In const A& newA1 = getA1(); does standard guarantees that temporary bound by a const
reference will not be destroyed until the reference goes out of scope?

No. The following is an example of that:

A const & newConstA3 = getA3 ();

Here, getA3() returns a temporary and the lifetime of that temporary is now bound to the object newConstA3. In other words the temporary will exist until newConstA3 goes out of scope.

More Related Contents:

  1. C++ Return value, reference, const reference
  2. const reference to a temporary object becomes broken after function scope (life time)
  3. Why can’t I make a vector of references?
  4. Why are arrays of references illegal?
  5. Why are references not reseatable in C++
  6. How are references implemented internally?
  7. C++: const reference, before vs after type-specifier
  8. difference between a pointer and reference parameter?
  9. Returning temporary object and binding to const reference [duplicate]
  10. Difference between pointer to a reference and reference to a pointer
  11. What’s the meaning of * and & when applied to variable names?
  12. Function pointer vs Function reference
  13. constant references with typedef and templates in c++
  14. C++: Argument Passing “passed by reference”
  15. Why does storing references (not pointers) in containers in C++ not work?
  16. C++ constant reference lifetime (container adaptor)
  17. C++ auto vs auto&
  18. warning: returning reference to temporary
  19. Why can’t I do polymorphism with normal variables?
  20. What is the difference between a const reference and normal parameter?
  21. Why doesn’t reference-to-member exist in C++?
  22. Difference between const. pointer and reference?
  23. Dangling references and undefined behavior
  24. Strange behavior of const_cast [duplicate]
  25. C++: difference between ampersand “&” and asterisk “*” in function/method declaration?
  26. dereferencing a pointer when passing by reference
  27. What is the proper way to return an object from a C++ function?
  28. Reference to a pointer
  29. Literal initialization for const references
  30. Both asterisk and ampersand in a parameter

Leave a Comment