atomic.SwapInt64() Function in Golang With Examples

In Go language, atomic packages supply lower-level atomic memory that is helpful is implementing synchronization algorithms. The SwapInt64() function in Go language is used to atomically store new value into *addr and returns the previous *addr value. This function is defined under the atomic package. Here, you need to import "sync/atomic" package in order to use these functions. Syntax:

func SwapInt64(addr *int64, new int64) (old int64)

Here, addr indicates address. And new is the new int64 value and old is the older int64 value. Note: (*int64) is the pointer to a int64 value. However, int64 contains the set of all signed 64-bit integers from -9223372036854775808 to 9223372036854775807. Return value: It stores the new int64 value into the *addr and returns the previous *addr value. Example 1: C

// Program to illustrate the usage of
// SwapInt64 function in Golang

// Including main package
package main

// Importing fmt and sync/atomic
import (
    "fmt"
    "sync/atomic"
)

// Main function
func main() {

    // Assigning value to int64
    var x int64 = 25786808555

    // Using SwapInt64 method 
    // with its parameters
    var old_val = atomic.SwapInt64(&x, 4567898196323)

    // Prints new and old value
    fmt.Println("Stored new value: ", 
         x, ", Old value: ", old_val)
}

Output:

Stored new value:  4567898196323, Old value:  25786808555

Example 2: C

// Program to illustrate the usage of
// SwapInt64 function in Golang

// Including main package
package main

// Importing fmt and sync/atomic
import (
    "fmt"
    "sync/atomic"
)

// Main function
func main() {

    // Assigning value to int64
    var m int64 = 78453984556
    var n int64 = 364576677888

    // Using SwapInt64 method with its parameters
    var oldVal1 = atomic.SwapInt64(&m, 78453984556)
    var oldVal2 = atomic.SwapInt64(&n, 935128383)

    // Prints output
    fmt.Println((oldVal1) == m)
    fmt.Println((oldVal2) == n)
}

Output:

true
false

Here, the oldVal1 is equal to "m" as the new value to be stored in the *addr is same as the old value so true is returned but oldVal2 is not equal to "n" as there the old value is not similar to the newly assigned value hence, false is returned.