atomic.AddInt32() Function in Golang With Examples

In Go language, atomic packages supply lower-level atomic memory that is helpful is implementing synchronization algorithms. The AddInt32() function in Golang is used to atomically add delta to the *addr. This function is defined under the atomic package. Here, you need to import “sync/atomic” package in order to use these functions.

Syntax:

func AddInt32(addr *int32, delta int32) (new int32)

Here, addr indicates address and delta indicates a small number of bits greater than zero.

Note: (*int32) is the pointer to a int32 value. Moreover, int32 contains the set of all signed 32-bit integers from -2147483648 to 2147483647.
Return value: It adds addr and delta atomically and returns a new value.

Example 1:

Go

// Golang Program to illustrate the usage of
// AddInt32 function

// Including main package
package main

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

// Main function
func main() {

    // Assigning values to the int32
    var (
        i int32 = 97
        j int32 = 48
        k int32 = 34754567
        l int32 = -355363
    )

    // Assigning constant
    // values to int32
    const (
        x int32 = 4
        y int32 = 2
    )

    // Calling AddInt32 method
    // with its parameters
    res_1 := atomic.AddInt32(&i, y)
    res_2 := atomic.AddInt32(&j, y-1)
    res_3 := atomic.AddInt32(&k, x-1)
    res_4 := atomic.AddInt32(&l, x)

    // Displays the output after adding
    // addr and delta atomically
    fmt.Println(res_1)
    fmt.Println(res_2)
    fmt.Println(res_3)
    fmt.Println(res_4)
}

Output:

99
49
34754570
-355359

Example 2:

Go

// Golang Program to illustrate the usage of
// AddInt32 function

// Including main package
package main

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

// Defining addr of type int32
type addr int32

// function that adds addr and delta
func (x *addr) add() int32 {

    // Calling AddInt32() function
    // with its parameter
    return atomic.AddInt32((*int32)(x), 2)
}

// Main function
func main() {

    // Defining x
    var x addr

    // For loop to increment
    // the value of x
    for i := 1; i < 7; i++ {

        // Displays the new value
        // after adding delta and addr
        fmt.Println(x.add())
    }
}

Output:

2
4
6
8
10
12

In the above example, we have defined a function add that returns the output returned from calling AddInt32 method. In the main function, we have defined a “for” loop that will increment the value of ‘x’ in each call. Here, the second parameter of the AddInt32() method is constant and only the value of the first parameter is variable. However, the output of the previous call will be the value of the first parameter of the AddInt32() method in the next call until the loop stops.

Lets see how above example works:

1st parameter = 0, 2nd parameter = 2   // returns ( 0 + 2 = 2)

// Now, the above output is 1st parameter in next call to AddInt32() method
1st parameter = 2, 2nd parameter = 2   // returns ( 2 + 2 = 4)
1st parameter = 4, 2nd parameter = 2   // returns ( 4 + 2 = 6) and so on.