On 2023-01-24 10:34:01 -0600, David Wright wrote:
> On Tue 24 Jan 2023 at 17:18:17 (+0100), Vincent Lefevre wrote:
> > On 2023-01-22 15:35:08 -0500, Greg Wooledge wrote:
> > > It doesn't work, presumably for the same reason that Ctrl-C doesn't work.
> > > The xterm's pty's input buffer is full, and it simply ignores all keyboard
> > > input from that point forward.
> >
> > They are actually not ignored, but delayed by the terminal emulator.
> > This is an issue because Ctrl-C (the intr character) is normally
> > taken into account immediately (with a SIGINT generation), even if
> > earlier characters have not been read yet by the command.
> >
> > And this is apparently the same for the other special characters
> > as defined by stty.
>
> How did you determine that they're actually received by the terminal
> emulator after the buffer is full? IOW where are they being stored?
I don't know where they are stored (this is probably part of the
terminal code), but
1. Create file1 with
printf "%d\n" `seq 9999` > file1
2. Select the contents of file1.
3. In a terminal (xterm in my case), type "some_app ; cat > file2",
where some_app is an X application or "sleep 10", for instance.
4. Paste with the middle button in the terminal.
5. Type Ctrl-C in the terminal.
6. Quit some_app (or let it end, e.g. in case of sleep).
I get something like:
[...]
9982
9983
9984
9985
9986
9987
99^C
in the terminal, and file2 ends with "9987" due to the Ctrl-C.
Another try:
[...]
9979
9980
9981
9982
9983
9984
99^C
and this time, the file ends with "9912". This is not surprising
as the characters probably appear in the terminal before they are
processed by "cat". Since the writes to the pty by xterm and the
process by "cat" are concurrent, one doesn't exactly obtain the
same result at each test. But in every case, the Ctrl-C is taken
into account only near the end.
And a test with GNOME Terminal:
[...]
9996
9997
9998
9999
^C
and the file ends with "9181".
--
Vincent Lefèvre <vinc...@vinc17.net> - Web: <https://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
