Re: strange char echo

[Thomas Dickey]

On Tue, 10 Nov 2009, Bryan Christ wrote:

> I added these lines to my application (after initscr) and the problem
> went away...
>
> tcgetattr(STDIN_FILENO,&term_desc);
> term_desc.c_lflag &= ~(ECHO);
> tcsetattr(STDIN_FILENO,TCSADRAIN,&term_desc);
>
> The version of ncurses I am using is:
> ncurses = 5.7 (20081102)
>
> Any known bugs of this nature with this build?

not that I recall - low-level I/O was not touched much for a while.

(this year, I've made a number of changes, and broken initialization 2-3
times)

> On Fri, 2009-11-06 at 21:36 +0000, Thomas Dickey wrote:
> > On Fri, 6 Nov 2009, Bryan Christ wrote:
> >
> > > Now that I think of it, I've only seen this problem when I try to run my
> > > software on a remote systems via SSH.  I just tried to reproduce it
> > > locally and couldn't.  The problem manifests 9 out of 10 times on remote
> > > connections.  When I tried it 10 times locally, 100% pass.
> > >
> > > Thoughts?
> >
> > just guessing - ssh may not be passing the ioctl information along
> > fast enough to make it look as if it succeeded.
> >
> > I'd investigate it by building the application with ncurses' tracing
> > turned on (normally a feature of the debug-library...).
> >
> > > On Thu, 2009-11-05 at 23:56 +0000, Thomas Dickey wrote:
> > > > On Thu, 5 Nov 2009, Bryan Christ wrote:
> > > >
> > > > > does anyone know what might cause characters to be echoed to the screen
> > > > > even though noecho() was called at startup?
> > > >
> > > > aside from a new bug report?
> > > >
> > > > It's possible that the ioctl to disable echoing is failing, e.g., if
> > > > stdout is redirected.
> > > >
> > > > (n)curses disables echo at initialization, and simulates the echo/noecho
> > > > behavior.

--
Thomas E. Dickey
http://invisible-island.net
ftp://invisible-island.net