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What does "atomic" mean in programming? - Stack Overflow
"An operation acting on shared memory is atomic if it completes in a single step relative to other threads. When an atomic store is performed on a shared memory, no other thread can observe the modification half-complete. When an atomic load is performed on a shared variable, it reads the entire value as it appeared at a single moment in time."
What are atomic operations for newbies? - Stack Overflow
Here, each upsert is atomic: the first one left count at 2, the second one left it at 3. 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 ...
atomic operations and atomic transactions - Stack Overflow
Atomic Operations on the other hand are usually associated with low-level programming with regards to multi-processing or multi-threading applications and are similar to Critical Sections. For example, if two threads both access and modify the same variable, each thread goes through the following steps:
thread safety - Atomic operations in ARM - Stack Overflow
Generally I would suggest that one confine use of them to small methods like "atomic increment" and such, which could easily be rewritten if needed to use other approaches (e.g. on the Cortex-M0, they'd be implemented by temporarily disabling interrupts). –
How are atomic operations implemented at a hardware level?
The atomic instructions involve utilizing a lock prefix on the instruction and having the destination operand assigned to a memory address. The following instructions can run atomically with a lock prefix on current Intel processors: ADD, ADC, AND, BTC, BTR, BTS, CMPXCHG, CMPXCH8B, DEC, INC, NEG, NOT, OR, SBB, SUB, XOR, XADD, and XCHG.
sql - What is atomicity in dbms - Stack Overflow
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.
c++ - What exactly is std::atomic? - Stack Overflow
std::atomic<> wraps operations that, in pre-C++ 11 times, had to be performed using (for example) interlocked functions with MSVC or atomic bultins in case of GCC. Also, std::atomic<> gives you more control by allowing various memory orders that specify synchronization and ordering constraints. If you want to read more about C++ 11 atomics and ...
What is the difference between atomic and critical in OpenMP?
Atomic Operations. If, as in the example above, our critical section is a single assignment, OpenMP provides a potentially more efficient way of protecting this. OpenMP provides an atomic directive which, like critical, specifies the next statement must be done by one thread at a time: #pragma omp atomic global_data++; Unlike a critical directive:
Is a single SQL Server statement atomic and consistent?
Atomic: either all of its data modifications are performed, or none of them is performed. Consistent : When completed, a transaction must leave all data in a consistent state. Isolated : Modifications made by concurrent transactions must be isolated from the modifications made by any other concurrent transactions.
How to do an atomic increment and fetch in C? - Stack Overflow
I'm looking for a way to atomically increment a short, and then return that value. I need to do this both in kernel mode and in user mode, so it's in C, under Linux, on Intel 32bit architecture.
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