Understanding the Usage of golang atomic LoadInt32/StoreInt32 (64)

Atomic operations play a crucial role in concurrent programming, ensuring the integrity of shared data across multiple goroutines. The sync/atomic package provides atomic load and store operations specifically for manipulating 32-bit and 64-bit integers.

Purpose of Atomic Operations

Unlike regular loads and stores, which are not guaranteed to be atomic on all CPU architectures, atomic operations enforce atomicity. This means that modifications to the shared variable using atomic operations appear to happen all at once, without any partial modifications visible to other goroutines.

Usage of LoadInt32/StoreInt32 (64)

In the example provided, sharedA is a 64-bit integer accessed by multiple goroutines. To ensure that all changes to sharedA are visible to all goroutines, you should use the atomic.LoadInt64 and atomic.StoreInt64 functions instead of regular loads and stores.

import "sync/atomic"

...
var sharedA int64
...
// concurent code
tmpVarA := atomic.LoadInt64(&sharedA)
atomic.StoreInt64(&sharedA, newValue)

In this example, tmpVarA contains the latest value of sharedA atomically. The atomic.StoreInt64 function also sets the value of sharedA to newValue atomically, ensuring that all goroutines see the correct value.

Ordering Guarantees

The use of atomic operations also provides certain ordering guarantees. The CPU typically has a memory model that defines the order in which memory operations are observed by other CPUs. By using atomic operations, you can influence this ordering and ensure that specific memory operations are performed in a certain sequence, even across different goroutines.

Conclusion

Atomic operations are essential in concurrent programming to maintain data consistency and provide ordering guarantees. By utilizing functions like atomic.LoadInt32/StoreInt32 (64), you can ensure the integrity of shared data across multiple goroutines, preventing data corruption and race conditions.