Re: Ncurses 5.9 -> 6.0 - libform

[Thomas Dickey]

On Fri, May 15, 2020 at 01:45:14PM +0100, Mike Aubury wrote:
> Ok - heres a sample program - derived from calls detected using "ltrace"
> (its impossible to extract the main application into a small example) - so
> apologies for it being terrible, bad names, void*s' etc
> 
> This is run on a putty session with a wide screen (200 odd columns wide) -
> if you're running on anything else - you might need to adjust the
> window/field sizes

I think the problem is the "sleep" call.
That can interfere with flushing the output buffer.

However, I'm not certain, since in a quick build of 5.9 and 6.2-current,
both gave me a blank screen.  But replacing the sleep() with a wgetch()
(or "napms(6000)" should work) made both versions show text.

See attached
 
> #include <curses.h>
> #include <form.h>
> #include <panel.h>
> main() {
> void *ptr0=initscr ( ); //0x13c21e0
> void *ptr1=newwin (0, 0, 0, 0 ); //0x13d12a0
> void *ptr2=new_panel (ptr1 ); //0x13db400
> void *ptr7=derwin (ptr1, 1, 198, 0, 0 ); //0x13dbb60
> FIELD *ptr8=new_field (1, 5, 0, 0,0,0 ); //0x1375700
> set_field_buffer (ptr8, 0, "XXX") ;
> FIELD *ptr10=new_field (1, 193, 0, 5,0,0 ); //0x13de270
> set_field_buffer (ptr10, 0, "yyy") ;
> FIELD *fields[3];
> fields[0]=ptr8;
> fields[1]=ptr10;
> fields[2]=0;
> FORM *ptr12=new_form (fields ); //0x13757c0
> set_form_win (ptr12, ptr7) ;
> set_form_sub (ptr12, 0) ;
> post_form (ptr12 );
> set_current_field(ptr12,ptr10);
> pos_form_cursor (ptr12 );
> update_panels ( );
> doupdate ( );
> sleep(6);
  ^^^^^^^^
> endwin();
> }
> 
> 
> 
> When I run this against 5.9 - it displays.
> XXX  yyy
> 
> When I run against 6.0 - it displays nothing.
> 
> 
> On Fri, 15 May 2020 at 01:53, Thomas Dickey <address@hidden> wrote:
> 
> > On Thu, May 14, 2020 at 07:30:19PM +0100, Mike Aubury wrote:
> > > (I know this is probably getting filed under "not enough information", or
> > > "hey thats a really old version you have there", but just on the
> > > offchance someone might have some pointers...)
> > >
> > > I've got an application that's been working for years, and a client has
> > > just tried using it on Centos8 and a particular command (a "prompt")
> > > doesnt work..
> > >
> > > In the app - i open a form with a label and a field, get them to type in
> > a
> > > value and return it.
> > > Centos comes with ncurses 6.2, I also tried 6.0 and it also breaks, but
> > > ncurses 5.9 on the same machine works fine.
> > >
> > > So - does anyone have any ideas on why fields might not be displaying on
> > > 6.0, when it worked fine on 5.9, or have any ideas of what I can do to
> > > troubleshoot?
> >
> > not offhand (that's several years).  I don't recall any particular
> > changes in the form library, but a quick diff shows that about 10%
> > of the source changed since 5.9 (a lot of that would be cosmetic,
> > but still...)
> >
> > If it's something that I could test, I could look into it.
> >
> > --
> > Thomas E. Dickey <address@hidden>
> > https://invisible-island.net
> > ftp://ftp.invisible-island.net
> >

-- 
Thomas E. Dickey <address@hidden>
https://invisible-island.net
ftp://ftp.invisible-island.net

demo_forms.c
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doit
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testit
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