Do I have to use atomic for “exit” bool variable?

by

Do I have to use atomic for “exit” bool variable?

Yes.

Either use atomic<bool>, or use manual synchronization through (for instance) an std::mutex. Your program currently contains a data race, with one thread potentially reading a variable while another thread is writing it. This is Undefined Behavior.

Per Paragraph 1.10/21 of the C++11 Standard:

The execution of a program contains a data race if it contains two conflicting actions in different threads,
at least one of which is not atomic, and neither happens before the other. Any such data race results in
undefined behavior.

The definition of “conflicting” is given in Paragraph 1.10/4:

Two expression evaluations conflict if one of them modifies a memory location (1.7) and the other one
accesses or modifies the same memory location.

More Related Contents:

  1. Where is the lock for a std::atomic?
  2. When do I really need to use atomic instead of bool? [duplicate]
  3. Will two atomic writes to different locations in different threads always be seen in the same order by other threads?
  4. Why don’t compilers merge redundant std::atomic writes?
  5. What exactly is std::atomic?
  6. How to implement multithread safe singleton in C++11 without using
  7. Implementing 64 bit atomic counter with 32 bit atomics
  8. Mixing C++11 atomics and OpenMP
  9. How to declare a vector of atomic in C++
  10. What do each memory_order mean?
  11. Is there any compiler barrier which is equal to asm(“” ::: “memory”) in C++11?
  12. How to atomically update a maximum value?
  13. For purposes of ordering, is atomic read-modify-write one operation or two?
  14. Why is the volatile qualifier used through out std::atomic?
  15. Why are std::atomic objects not copyable?
  16. C++11: the difference between memory_order_relaxed and memory_order_consume
  17. How do memory_order_seq_cst and memory_order_acq_rel differ?
  18. c++, std::atomic, what is std::memory_order and how to use them?
  19. Understanding std::atomic::compare_exchange_weak() in C++11
  20. Double-Checked Lock Singleton in C++11
  21. C++11 memory_order_acquire and memory_order_release semantics?
  22. [[carries_dependency]] what it means and how to implement
  23. Acquire/Release versus Sequentially Consistent memory order
  24. Is local static variable initialization thread-safe in C++11? [duplicate]
  25. Does constexpr imply inline?
  26. Do rvalue references allow dangling references?
  27. What is std::promise?
  28. Random output different between implementations
  29. How can I pass std::unique_ptr into a function
  30. Deprecated throw-list in C++11

Leave a Comment