Golang : Fix cannot use buffer (type bytes.Buffer) as type io.Writer(Write method has pointer receiver) error
Problem :
You created a variable of type bytes.Buffer and encounter this error message when you want to use the variable with bufio.NewWriter() function.
cannot use buffer (type bytes.Buffer) as type io.Writer in argument to bufio.NewWriter: bytes.Buffer does not implement io.Writer (Write method has pointer receiver)
Solution :
From https://golang.org/pkg/bufio/#NewWriter, the NewWriter() will return a pointer *Writer . i.e this explains part the of the error message - Write method has pointer receiver.
To fix this error, you need to provide the memory address of the buffer. In this code example below, you will see that bytes.NewBuffer(nil) is the same as &bytes.Buffer{} and os.Stdout is ok because the underlaying is a pointer of *File type.
package main
import (
"bufio"
"fmt"
"os"
"bytes"
)
func main() {
// redirect to screen, not an issue because os.Stdout is a pointer
screenWriter := bufio.NewWriter(os.Stdout)
fmt.Fprint(screenWriter, "Hello world! 你好世界!\n")
screenWriter.Flush() // Don't forget to flush!
// redirect to buffer
//var buffer bytes.Buffer
//bufferWriter := bufio.NewWriter(buffer) // <--- not ok, will generate error message
//bufferWriter := bufio.NewWriter(&buffer) // <-- ok
buffer := bytes.NewBuffer(nil) // same as &bytes.Buffer{}, so it is ok as well.
bufferWriter := bufio.NewWriter(buffer)
bufferWriter.Flush() // Don't forget to flush!
}
References :
https://www.socketloop.com/references/golang-bufio-newwriter-function-example
See also : Golang : Reset buffer example
By Adam Ng
IF you gain some knowledge or the information here solved your programming problem. Please consider donating to the less fortunate or some charities that you like. Apart from donation, planting trees, volunteering or reducing your carbon footprint will be great too.
Advertisement
Tutorials
+5.6k Golang : Clean formatting/indenting or pretty print JSON result
+9.8k Golang : Secure(TLS) connection between server and client
+2.2k Fix Google Analytics Redundant Hostnames problem
+2.9k Javascript : Get operating system and browser information
+8.9k Golang : Clean up null characters from input data
+1.7k Facebook : How to place save to Facebook button on your website
+28.9k Golang : convert(cast) bytes to string
+10.3k Golang : Get all upper case or lower case characters from string example
+6.3k Golang : How to get URL port?
+3.8k Golang : How to generate Code 39 barcode?
+4.5k Golang : Convert decimal number(integer) to IPv4 address
+6.5k Golang : How to make a file read only and set it to writable again?