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...
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.
Everything works. Note that "atomic" is contextual: in this case, the upsert operation only needs to be atomic with respect to operations on the answers table in the database; the computer can be free to do other things as long as they don't affect (or are affected by) the result of what upsert is trying to do.
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 remember I came across certain types in the C language called atomic types, but we have never studied them. So, how do they differ from regular types like int,float,double,long etc., and what are...
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 ...
Ex: std::atomic_bool, std::atomic_uint_least32_t, etc. How to share atomic_* types in source code which compiles in both C and C++ If you are trying to share some source code snippets with C, however, so that they can compile in C or C++, then you cannot prefix C source code variables with std::.
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?
