How to read the contents of a file using syscall in Golang?

Syntax:

func Read(fd int, p []byte) (n int, err error)

Consider the below example demonstrating how to read the contents of a file using syscall in Golang?

The file is:

File name: test.txt
File content:
Hello, world! How are you?

Program:

package main

import (
	"fmt"
	"syscall"
)

func main() {
	// Creating a byte buffer to
	// store the file's content
	var filedata = make([]byte, 64)
	// Opening the file in Read-only mode
	fd, err := syscall.Open("test.txt", syscall.O_RDONLY, 0777)
	if err != nil {
		fmt.Println("Err:", err)
	}
	for {
		// Reading the content
		len, _ := syscall.Read(fd, filedata)
		if len <= 0 {
			break
		}
		
		fmt.Println("The file's content is...")
		fmt.Print(string(filedata[:len]))
	}
}

Output

The file's content is...
Hello, world! How are you?