frame-visible-p and suspend-tty

frame-visible-p and suspend-tty

[Eli Zaretskii]

The documentation of frame-visible-p says:

    On a text-only terminal, all frames are considered visible, whether
    they are currently being displayed or not, and this function returns
    @code{t} for all frames.

What about a text-only terminal that has been suspended?  The frames
on such a terminal are neither visible nor being updated, and yet this
function seems to still return t for them (unless my testing was
faulty).  That doesn't sound right.

Re: frame-visible-p and suspend-tty

[Chong Yidong]

Eli Zaretskii <eliz@gnu.org> writes:

> The documentation of frame-visible-p says:
>
>     On a text-only terminal, all frames are considered visible, whether
>     they are currently being displayed or not, and this function returns
>     @code{t} for all frames.
>
> What about a text-only terminal that has been suspended?  The frames
> on such a terminal are neither visible nor being updated, and yet this
> function seems to still return t for them (unless my testing was
> faulty).  That doesn't sound right.

IIUC, a text terminal cannot be suspended unless it is the only existing
terminal.  In that case, how would this function run?

Re: frame-visible-p and suspend-tty

[Eli Zaretskii]

> From: Chong Yidong <cyd@stupidchicken.com>
> Cc: emacs-devel@gnu.org
> Date: Sat, 17 Jan 2009 14:28:41 -0500
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > The documentation of frame-visible-p says:
> >
> >     On a text-only terminal, all frames are considered visible, whether
> >     they are currently being displayed or not, and this function returns
> >     @code{t} for all frames.
> >
> > What about a text-only terminal that has been suspended?  The frames
> > on such a terminal are neither visible nor being updated, and yet this
> > function seems to still return t for them (unless my testing was
> > faulty).  That doesn't sound right.
> 
> IIUC, a text terminal cannot be suspended unless it is the only existing
> terminal.

??? suspend-tty works _only_ if at least one more terminal exists, see
its docs.

Re: frame-visible-p and suspend-tty

[Chong Yidong]

Eli Zaretskii <eliz@gnu.org> writes:

>> IIUC, a text terminal cannot be suspended unless it is the only
>> existing terminal.
>
> ??? suspend-tty works _only_ if at least one more terminal exists, see
> its docs.

OK---I got confused.  Could you test whether this patch DTRT?

*** trunk/src/frame.c.~1.410.~	2009-01-14 08:29:56.000000000 -0500
--- trunk/src/frame.c	2009-01-17 14:23:45.000000000 -0500
***************
*** 1957,1975 ****
  a window system, it may not show at all.
  Return the symbol `icon' if frame is visible only as an icon.
  
! On a text-only terminal, all frames are considered visible, whether
! they are currently being displayed or not, and this function returns t
! for all frames.  */)
       (frame)
       Lisp_Object frame;
  {
    CHECK_LIVE_FRAME (frame);
  
!   FRAME_SAMPLE_VISIBILITY (XFRAME (frame));
  
!   if (FRAME_VISIBLE_P (XFRAME (frame)))
      return Qt;
!   if (FRAME_ICONIFIED_P (XFRAME (frame)))
      return Qicon;
    return Qnil;
  }
--- 1957,1979 ----
  a window system, it may not show at all.
  Return the symbol `icon' if frame is visible only as an icon.
  
! On a text-only terminal, a frame is considered visible if and only if
! its terminal is active (i.e., not suspended), regardless of whether it
! is currently being displayed.  */)
       (frame)
       Lisp_Object frame;
  {
+   struct frame *f;
    CHECK_LIVE_FRAME (frame);
+   f = XFRAME (frame);
  
!   FRAME_SAMPLE_VISIBILITY (f);
  
!   if (FRAME_TERMCAP_P (f))
!     return (f->terminal->display_info.tty->output ? Qt : Qnil);
!   if (FRAME_VISIBLE_P (f))
      return Qt;
!   if (FRAME_ICONIFIED_P (f))
      return Qicon;
    return Qnil;
  }