- What are atomic types in the C language? - Stack Overflow
The type sig_atomic_t is always an integer data type, but which one it is, and how many bits it contains, may vary from machine to machine Data Type: sig_atomic_t This is an integer data type Objects of this type are always accessed atomically In practice, you can assume that int is atomic You can also assume that pointer types are atomic
- c++ - How to Use std::atomic_bool or std::atomic_flag . . . - Stack Overflow
std::atomic_flag has a harder interface, it is designed as a building block for mutexes and spinlocks for an atomic bool you should use std::atomic_bool and before C++20 you couldn't even read or set std::atomic_flag without doing an RMW with test_and_set which is a slow operation, which made std::atomic_flag slower than std::atomic_bool when
- c - gcc builtin atomic compare and exchange - Stack Overflow
If it's null, break out of the loop and return failure If it's not null, use that old value as the "expected" for atomic compare-and-exchange If it succeeds, exit the loop and return success Otherwise repeat By the way, this general approach is how you construct arbitrary atomic operations on top of compare-and-exchange
- What is the difference between this atomic Rust code and its non . . .
In the atomic case, the use of fetch_or guarantees that the whole read-modify-write cycle is atomic In both cases, since the ordering is relaxed, the writes to layer2 and layer3 may seem to occur in any order as seen from other threads The comment inside add_atomic is meant avoid an issue
- c++ - Correct usage of std::atomic - Stack Overflow
The std::atomic works on a "bag of bits": an object of type T whose bitwise representation, stored in sizeof(T) bytes, carries the whole value It means that nothing that needs to atomically manipulated (by these specific operations on std::atomic<T>) can reside in an object pointed to by a member of T, that would never work
- Can you read the value of std::atomic_flag without modifying it?
On some platforms the only atomic instructions are exchange instructions On such platforms, std::atomic_flag::test_and_set() can be implemented with exchange var,1 and clear() with exchange var,0, but there is no atomic instruction for reading the value So, if you want to read the value without changing it, then you need std::atomic<bool>
- Which is threadsafe atomic or non atomic? - Stack Overflow
Question Expanded: Suppose there is an atomic string property called "name", and if you call [self setName:@"A"] from thread A, call [self setName:@"B"] from thread B, and call [self name] from thread C, then all operation on different thread will be performed serially which means if one thread is executing setter or getter, then other threads will wait
- pthreads - c++ atomic vs lock - Stack Overflow
The atomic solution, on x86 will be a simple "lock add" operation On other processors it may be more complex, but even so, the atomic is the minimum required for a mutex, so you have AT least that amount of work anyway Then you add the mutex unlock, which may not be quite as complex, but it will not be completely free So, yes, go for atomic
|