Re: Invisible form fields w/ ncurses-5.7 on Fedora

[Thomas Dickey]

On Fri, 12 Aug 2011, Grant Edwards wrote:

> On 2011-08-12, Thomas Dickey <address@hidden> wrote:
> > On Fri, 12 Aug 2011, Grant Edwards wrote:
> > > On 2011-08-12, Grant Edwards <address@hidden> wrote:
> > >
> > > > I'm sure it's something I'm doing wrong in my application, but I can't
> > > > figure out what it might be.
> > >
> > > Doh!  After beating my head against the wall for a day and a half, it
> > > only takes 5 miutes after posting to stumble across the problem.
> > >
> > > There was a type in my code:
> > >
> > >   w = newwin(rows,cols,y,x);                     assert(w);
> > >   s = derwin(w,rows-2,cols-2,1,1);               assert(s);
> > >   set_form_win(f,w);
> > >   set_form_win(f,s);
> > >
> > > That second set_form_win() call should have been set_form_sub().
> > >
> > > I've no clue why my broken code worked for so long on so many systems
> > > and just recently failed only on Fedora systems.
> >
> > perhaps just different memory layout.  I come across very old bugs
> > periodically, and wonder how they escaped notice for so long.  I don't
> > recall anything special about set_form_win - looking at the change
> > history, I see that I made a macro substitution in this code in 2009/11/07
> > - and somewhat earlier in 2009 was working to merge Juergen's changes,
> > that affected the internals.  So if your two "5.7" versions fell on each
> > side of that timespan, then there might be some breakage for me to
> > investigate.
>
> I assume that the version with two set_form_win() calls wouldn't be
> expected to work, so I don't think there's anything that really needs
> to be investigated.  But, if you'd like I can track down the details
> for the two different "5.7" libraries.

That might help (at least me, so I could see why the behavior changed).
Since the application code was incorrect, then it might have been a
fix in ncurses (not certain...).


> FWIW, on the Fedora system (where my old code didn't work), it behaved
> the same way with 5 different terminals (gnome, aterm, xterm, rxvt,
> Eterm): when the "form" was displayed the cursor was visible and just
> sat on the upper-left-hand border of the form dialog window until I
> hit the key that took down the form dialog.
>
> Changing the second set_form_win() call to set_form_sub() makes it
> work as expected everywhere.
>
> --
> Grant Edwards               grant.b.edwards        Yow! I'm rated PG-34!!
>                                  at
>                              gmail.com
>
>
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--
Thomas E. Dickey
http://invisible-island.net
ftp://invisible-island.net