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RE: question about `display-graphic-p' and emacs daemon
From: |
Drew Adams |
Subject: |
RE: question about `display-graphic-p' and emacs daemon |
Date: |
Wed, 21 Nov 2012 08:27:53 -0800 |
> > 1. I have a defcustom that has this as the initial value:
> >
> > (and (fboundp 'image-file-name-regexp)
> > (if (fboundp 'display-graphic-p)
> > (display-graphic-p)
> > window-system)
> > t)
> >
> > With emacs daemon, loading the file with that sexp raises an error,
> > because it is eval'd before the first frame is displayed.
>
> I think this form evals just fine - (display-graphic-p) is always nil,
> though.
Ah, then I misunderstood the problem, which Christopher reported originally. I
thought an error was raised.
> > As a workaround, I can remove the `display-graphic-p'/`window-system'
> > test and do that only at runtime (after a frame has been displayed).
> >
> > But shouldn't it be possible for Emacs to determine the display type
> > without actually displaying a frame? Naive question, but I'm
> > ignorant. If that is possible, what is the test to do it?
>
> A daemonized Emacs can have multiple frames that use either a window
> system or a terminal - at the same time! That is (display-graphic-p)
> can eval to either t or nil within the same Emacs process,
> depending on the selected frame.
Got it. So I will use both the original defcustom sexp and a runtime,
frame-specific check. Thx.
(My questions about the doc of "display" remain, however.)