How to Use sync/atomic Package in Go

Concurrency
2026-04-17T12:05:42+00:00
Use sync/atomic for fast, lock-free updates to int64, uint64, and pointer variables in concurrent Go programs.

Use sync/atomic to perform lock-free, thread-safe operations on specific variable types like int64, uint64, and uintptr without the overhead of sync.Mutex.

package main

import (
	"fmt"
	"sync/atomic"
)

var counter int64

func main() {
	// Atomically add 1 to counter
	atomic.AddInt64(&counter, 1)
	
	// Atomically load the current value
	val := atomic.LoadInt64(&counter)
	
	fmt.Println(val)
}

Key Functions:

  • atomic.LoadInt64(addr) / atomic.StoreInt64(addr, val): Read and write values.
  • atomic.AddInt64(addr, delta): Add a value and return the new result.
  • atomic.CompareAndSwapInt64(addr, old, new): Swap only if the current value matches old.
  • atomic.LoadPointer(addr) / atomic.StorePointer(addr, ptr): For pointers (use unsafe.Pointer).

Important: You must pass the address of the variable (&counter) to these functions. Do not use sync/atomic for complex types like slices or maps; use sync.Mutex or sync.RWMutex for those.