golang CopyN

The CopyN function in Go is used to copy at most n bytes from the source slice to the destination slice. It returns the number of bytes copied and an error if any.

The function signature is as follows:

func CopyN(dst []Type, src []Type, n int) int

Here, dst is the destination slice, src is the source slice, and n is the maximum number of bytes to be copied.

Example:

package main

import (
    "fmt"
)

func main() {
    src := []byte("Hello, World!")
    dst := make([]byte, 5)

    n := CopyN(dst, src, 5)

    fmt.Println(string(dst)) // Output: Hello
    fmt.Println(n) // Output: 5
}

In this example, we have a source slice src and a destination slice dst. We want to copy at most 5 bytes from src to dst. We call the CopyN function with dst, src, and 5 as arguments. The function returns the number of bytes copied, which is 5. We then print the contents of dst, which is Hello