This is the mail archive of the cygwin-developers mailing list for the Cygwin project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH v3 0/1] Pseudo console support in PTY (v3)

Am 07.04.2019 um 07:05 schrieb Takashi Yano:
Hi Thomas,

Thank you very much for testing.
You're welcome; I'm very interested in this solution, not only, but also because the interoperability problems cause a series of problem reports to mintty.

On Sat, 6 Apr 2019 23:33:04 +0200 Thomas Wolff wrote:
Terminal reports "\033[6n" and "\033[0c" are apparently emulated and
sent in reverse order;
response to primary device attribute request is wrong (not what mintty
would report).
There is no response to secondary device attribute request ("\033[>0c")
and others,
e.g. '\033[18t' or '\033]10;?\033\' and many others; why can't these
requests be passed to the terminal and handled transparently? (You
explained something around handles before but I don't get the point.)
This is not caused by my intercept, but pseudo console itself.
Unfortunately, pseudo console is not transparent at all. Pseudo
console interprets VT100 sequences in output and processes them.
Then, it fowards another VT100 sequences to the pipe associated
with the pseudo console.
OK, understood. So ConPTY is not only a pty adapter but also a kind of half-terminal emulator, like tmux or screen.

Output to alternate screen seems to be forced to the primary screen, mostly;
if I try to switch screen in various ways (menu, echo "\033[?1047h" >
/dev/pty1, before or while cmd.exe runs),
behaviour appears to be inconsistent and not as expected (expected
behaviour is that any output goes to the active screen).
Hmmm, this may be caused by "synchronization". I will also check this.

Again, I don't see a need that you intercept this at all.
The patch attached disables all my intercept. It is against v3.
Please check the output from PTY using script command with this
patch. You can use your test case for the test. You will find many
VT100 ESC secuenses you don't write to console. These are written
by pseudo console itself.
OK, I may find time to analyse that. Meanwhile, my test case for the above unfortunately still fails with the "disabling" patch:
Start mintty, run `tty`, let's say it says /dev/pty0.
In mintty, run cmd.
In another shell (mintty or not), run echo "\033[?1047h" > /dev/pty0.
In mintty, in cmd, type dir... nothing happens. "dir" will be echoed and its output shown in unpatched cygwin.

Also, you can confirm screen layout is broken if you run cygwin
apps and native console apps alternately. "Synchronization" is
necessary to avoid this, I think.
I have not observed any "broken" screen layout, but I notice a cleared screen when starting cmd (does not clear in unpatched cygwin). Other non-cygwin programs, like java, do not clear the screen. Do you have an explanation?

On Sat, 6 Apr 2019 23:33:04 +0200 Thomas Wolff wrote:
Character output conversion works with my test program (using
WriteConsoleW). Using java, output works too (with proper java encoding
option), but non-ASCII input characters are replaced by and echoed as space.
Indeed... I will fix it.
Once, I thought I could reproduce, however, I cannot reproduce this
now. Could you please let me know how you tested.
I'm attaching my Java test program below.
I compile it with javac -encoding UTF-8 and run it with java -Dfile.encoding=UTF-8. This makes non-ASCII output work in a UTF-8 terminal. Non-ASCII input however is blanked.

Kind regards,


public class JavaPW
  public static void main(String args[]) throws IOException
    System.out.println("Writing Unicode: bäh 3€");

    BufferedReader rd = new BufferedReader(new InputStreamReader(, "UTF-8"));
    System.out.println("Reading input from");
    System.out.println("Please enter your input: ");
    String input = rd.readLine();
    System.out.println("User Input from " + input);

    Console console = System.console();
    System.out.println("Reading input from console");
    System.out.println("Please enter your input: ");
    input = console.readLine();
    System.out.println("User Input from console: " + input);

    System.out.println("Reading password from Console in Java: ");
    //password will not be echoed to console and stored in char array
    char[] password = console.readPassword();
    System.out.println("Password entered by user: " + new String(password));

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]