Read Operation in Go

When you want to read bytes into a buffer, you should use this definetion

buf1 := make([]byte, 3)

instead of this

var buf2 []byte

because buf2 is nil pointer to []byte, data only can be appended to it.

package main

import (
	"fmt"
	"strings"
)

func main() {

	var buf []byte
	buf1 := make([]byte, 3)
	fmt.Printf("%#v, %#v \n", buf, buf1)

	r := strings.NewReader("abcde")

	// Cauction: buf can not receive any bytes.
	n, err := r.Read(buf)
	fmt.Println(n, err)

	// buf1 can receive bytes.
	n, err = r.Read(buf1)
	fmt.Println(n, err)
}

// []byte(nil), []byte{0x0, 0x0, 0x0}
// 0 <nil>
// 3 <nil>

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