Why is the volatile qualifier used through out std::atomic?

by

To summarize what others have correctly written:

C/C++ volatile is for hardware access and interrupts. C++11 atomic<> is for inter-thread communication (e.g., in lock-free code). Those two concepts/uses are orthogonal, but they have overlapping requirements and that is why people have often confused the two.

The reason that atomic<> has volatile-qualified functions is the same reason it has const-qualified functions, because it’s possible in principle for an object be both atomic<> and also const and/or volatile.

Of course, as my article pointed out, a further source of confusion is that C/C++ volatile isn’t the same as C#/Java volatile (the latter is basically equivalent to C++11 atomic<>).

More Related Contents:

  1. When to use volatile with multi threading?
  2. What exactly is std::atomic?
  3. How to implement multithread safe singleton in C++11 without using
  4. Where is the lock for a std::atomic?
  5. Volatile in C++11
  6. Mixing C++11 atomics and OpenMP
  7. How to declare a vector of atomic in C++
  8. What do each memory_order mean?
  9. Does the C++ volatile keyword introduce a memory fence?
  10. When do I really need to use atomic instead of bool? [duplicate]
  11. Is there any compiler barrier which is equal to asm(“” ::: “memory”) in C++11?
  12. How to atomically update a maximum value?
  13. Why are std::atomic objects not copyable?
  14. Do I have to use atomic for “exit” bool variable?
  15. Understanding std::atomic::compare_exchange_weak() in C++11
  16. Double-Checked Lock Singleton in C++11
  17. C++11 make_pair with specified template parameters doesn’t compile
  18. Is a moved-from vector always empty?
  19. Significance of parentheses in decltype((c))?
  20. Why is modifying a string through a retrieved pointer to its data not allowed?
  21. std::put_time implementation status in GCC?
  22. Where can I learn more about C++0x? [closed]
  23. Why is locking a std::mutex twice ‘Undefined Behaviour’?
  24. Why would I ever use push_back instead of emplace_back?
  25. How to compile C++ with C++11 support in Mac Terminal
  26. Why can’t I use with g++ 4.9.2?
  27. C++11 Change `auto` Lambda to a different Lambda?
  28. Why does std::forward have two overloads?
  29. C++11 cross compiler/standard library random distribution reproducibility
  30. get part of std::tuple

Leave a Comment