atomic.SwapUintptr() Function in Golang With Examples

In Go language, atomic packages supply lower-level atomic memory that is helpful is implementing synchronization algorithms. The SwapUintptr() 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 SwapUintptr(addr *uintptr, new uintptr) (old uintptr)

Here, addr indicates address. And new is the new uintptr value and old is the older uintptr value. Note: (*uintptr) is the pointer to a uintptr value. And uintptr is an integer type that is too large that it can contain the bit pattern of any pointer. Return Value: It stores the new uintptr value into the *addr and returns the previous *addr value. Example 1: C

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

// Including main package
package main

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

// Main function
func main() {

    // Assigning value to uintptr
    var x uintptr = 96464646466757

    // Using SwapUintptr method 
    // with its parameters
    var old_val = atomic.SwapUintptr(&x,
                            21863567864)

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

Output:

Stored new value:  21863567864, Old value:  96464646466757

Example 2: C

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

// Including main package
package main

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

// Main function
func main() {

    // Assigning value to uintptr
    var m uintptr = 4235564747474
    var n uintptr = 2567891937466

    // Using SwapUintptr method with its parameters
    var oldVal1 = atomic.SwapUintptr(&m, 4235564747474)
    var oldVal2 = atomic.SwapUintptr(&n, 7454545419024)

    // 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 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.