Xref: utzoo comp.sources.d:6418 alt.sources.d:1435
Path: utzoo!utgpu!cs.utexas.edu!sdd.hp.com!usc!apple!agate!usenet.ins.cwru.edu!ncoast!allbery
From: allbery@NCoast.ORG (Brandon S. Allbery KB8JRR)
Newsgroups: comp.sources.d,alt.sources.d
Subject: Re: termcap and negative numbers
Message-ID: <1991Feb2.182324.4140@NCoast.ORG>
Date: 2 Feb 91 18:23:24 GMT
References: <17263@cgl.ucsf.EDU>
Reply-To: allbery@ncoast.ORG (Brandon S. Allbery KB8JRR)
Followup-To: comp.sources.d
Organization: North Coast Public Access Un*x (ncoast)
Lines: 24

As quoted from <17263@cgl.ucsf.EDU> by srp@babar.mmwb.ucsf.edu (Scott R. Presnell):
+---------------
| 	Is there a standard extention to the termcap source code that
| allows the extraction of negative numbers via the tgetnum() call?  Or has
| anyone implemented something like this?  I'm just looking for a precedent.
+---------------

Since -1 from tgetnum() means "capability not present", there's potential for
interpretation problems here.

Note that "not present" is quite different from "0" in some cases; consider
"sg#0" vs. "sg@".  The former is usually interpreted as the terminal has
"field" attributes which don't use visible screen memory, while the latter
means that the terminal has "character" attributes.  (I still argue that the
former is really the "ms@" attribute, but the current behavior is too well
entrenched now to be changed.)  Thus, the value "0" can't be used to say "not
present".

++Brandon
-- 
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