Objects of atomic types are the only C++ objects that are free from data races; that is, if one thread writes to an atomic object while another thread reads from it, the behavior is well-defined. In addition, accesses to atomic objects may establish inter-thread synchronization and order non-atomic memory accesses as specified by std::memory_order.
std::atomic is new feature introduced by c++11 but I can't find much tutorial on how to use it correctly. So are the following practice common and efficient? One practice I used is we have a buff...
The atomic "thing" in shared_ptr is not the shared pointer itself, but the control block it points to. meaning that as long as you don't mutate the shared_ptr across multiple threads, you are ok. do note that copying a shared_ptr only mutates the control block, and not the shared_ptr itself.
Can someone explain to me, whats the difference between atomic operations and atomic transactions? Its seems to me that these two are the same thing.Is that correct?
The last two are identical; "atomic" is the default behavior (note that it is not actually a keyword; it is specified only by the absence of nonatomic -- atomic was added as a keyword in recent versions of llvm/clang). Assuming that you are @synthesizing the method implementations, atomic vs. non-atomic changes the generated code. If you are writing your own setter/getters, atomic/nonatomic ...
The definition of atomic is hazy; a value that is atomic in one application could be non-atomic in another. For a general guideline, a value is non-atomic if the application deals with only a part of the value. Eg: The current Wikipedia article on First NF (Normal Form) section Atomicity actually quotes from the introductory parts above.
I read this in the book C# 6.0 and the .NET 4.6 framework: “assignments and simple arithmetic operations are not atomic”. So, what does it exactly mean?
You need atomic<bool> to avoid race-conditions. A race-condition occurs if two threads access the same memory location, and at least one of them is a write operation. If your program contains race-conditions, the behavior is undefined.
