在终端中关闭回显-Golang

Question

I'm trying to Turn off echoing in the terminal, in the Golang,

Code:

func main() {

    STDINFILE := os.Stdin
    STDINFILENO := 0

    raw, err := unix.IoctlGetTermios(STDINFILENO, unix.TCGETA)
    if err != nil {
        panic(err)
    }
    rawState := *raw

    rawState.Lflag &^= unix.ECHO

    err = unix.IoctlSetTermios(STDINFILENO, unix.TCSAFLUSH, &rawState)

    if err != nil {
        panic(err)
    }

    var charValue byte
    reader := bufio.NewReader(STDINFILE)

    for {
        var err error
        // read one byte
        charValue, err = reader.ReadByte()
        if err != nil {
            if err == io.EOF {
                fmt.Println("END OF FILE")
            }
        }
        // press q to quit.
        if charValue == 'q' {
            os.Exit(0)
        }

    }
}

But it's not working as expected

I'm still able to see the echoed value,

What I'm doing wrong, Can someone please point out to me or guide me?

Answer 1

The issue was with the tcsetattr - parameters err = unix.IoctlSetTermios(STDINFILENO, unix.TCSAFLUSH, &rawState)

With action TCSAFLUSH,

DOC SUGGEST:

TCSADRAIN Make the change after waiting until all queued output has been written. You should usually use this option when changing parameters that affect output. TCSAFLUSH This is like TCSADRAIN, but also discards any queued input.

So the termios in above case was sending back the character out to the left (the “master” pty), as ECHO was not off in this case until the output was written to the shell (the “slave” pty ).

Changing the action to TCSANOW - the change shall occur immediately turned the echo off immediately.