GNU bug report logs - #4827
23.1.50; frame-visible-p documentation

Previous Next

Full log

View this message in rfc822 format

From: stepnem <at> gmail.com
To: bug-gnu-emacs <at> gnu.org
Subject: bug#4827: 23.1.50; frame-visible-p documentation
Date: Thu, 29 Oct 2009 14:41:00 +0100

[In GNU Emacs 23.1.50.1 (i686-pc-linux-gnu, GTK+ Version 2.12.9)
 of 2009-10-28]

C-h f frame-visible-p:
"""
(frame-visible-p FRAME)

Return t if FRAME is now "visible" (actually in use for display).
A frame that is not "visible" is not updated and, if it works through
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.

"""

Could please someone explain a few points mentioned below, and if
possible, fix the docstring to make them clear without further
explanation?

1. What does "if it works through a window system" mean? I assume "it"
means "frame", but is "a frame works through a window system" a good
formulation?

2. Why say "if it works through a window system, it may not show at all"?
If I understand correctly, on a text-only terminal, i.e. without "a
window system", there can be only one frame really visible at a time
(i.e. not "visible", but visible); and according to the second
paragraph, all frames are "visible", i.e. considered visible -- so why
"if ..., it may not show at all"?

3. What does being visible only as an icon mean?

The second paragraph is quite clear, although I really would like to
know why is there no distinction regarding "visibility" in a terminal or
what is the motivation for such behaviour (i.e. returning t for all
frames).

As a suggestion, wouldn't it at least make more sense to start the first
paragraph with 'Under a window system...' and get rid of that unclear
conditional mentioned under 1. and 2. above?

Regards

Štěpán Němec 

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.