x/sys: provide termios.h-like functionality

[akevinbailey]

Go needs a way to flush the stdin before prompt and Scanln.

See odeke-em/drive#157 for psoible fix for Linux.

[adg]

This isn't a fmt issue. It's a feature request for a function that should probably be in the x/sys repo.

This is how @minux implemented it, by calling out to a C library: https://github.com/minux/drive/blob/2b076a3dc02b5fee728e9eeee8c089a414de5fbc/src/tty.go

[akevinbailey]

I disagree. Flushing stdio should be a basic function of GO without having to call an external C library. Java and Python have it built in.

[ianlancetaylor]

How do you flush standard input in Java and Python? Can you point to the docs?

Note that this issue is not about flushing standard output. Go can already do that perfectly well.

[akevinbailey]

Sorry, I meant stdin

Java:
System.in.read(new byte[System.in.available()]); // Flushes stdin

Python:
from termios import tcflush, TCIOFLUSH
tcflush(sys.stdin, TCIOFLUSH)

[adg]

On 12 November 2015 at 12:18, A. Kevin Bailey notifications@github.com
wrote:

from termios import tcflush, TCIOFLUSH
tcflush(sys.stdin, TCIOFLUSH)

This is the kind of thing I was suggesting in renaming this issue.

[tklauser]

Some of the termios.h function require more functionality than just mere syscall wrappers (which is the scope of the x/sys package) or they don't use any syscalls at all (like the cf* functions). Thus, it might be more appropriate to implement these functions in the (currently empty) x/term package? We may then make use of x/sys for certain parts of the implementation.

Also, some parts like cfmakeraw are already available in x/crypto/ssh/terminal and I guess we should move/copy them to x/term as well.