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...
In the Effective Java book, it states: The language specification guarantees that reading or writing a variable is atomic unless the variable is of type long or double [JLS, 17.4.7]. What do...
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.
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.
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 ...
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.
