Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!cwjcc!hal!ncoast!allbery
From: allbery@ncoast.UUCP (Brandon S. Allbery)
Newsgroups: comp.databases
Subject: Re: Informix problem with escape sequences
Message-ID: <12648@ncoast.UUCP>
Date: 2 Oct 88 19:40:48 GMT
References: <483@pan.UUCP> <860@vsi.UUCP> <262@fsc2086.UUCP>
Reply-To: allbery@ncoast.UUCP (Brandon S. Allbery)
Followup-To: comp.databases
Organization: Cleveland Public Access UN*X, Cleveland, Oh
Lines: 38

As quoted from <262@fsc2086.UUCP> by jim@fsc2086.UUCP (Jim O'Connor):
+---------------
| In article <860@vsi.UUCP>, sullivan@vsi.UUCP (Michael T Sullivan) writes:
| > In article <483@pan.UUCP>, jw@pan.UUCP (Jamie Watson) writes:
| > > The Informix products seem to be incapable of handling escape sequences,
| > > such as are generated by the arrow keys on ansi terminals, reliably.
| > 
| > Are you familiar with how h,j,k,l are used in vi?  h=left, j=down,
| > k=up, l=right.  In perform the control counterparts (^h,^j,^k,^l) do
| > the same thing.  Use these control characters, NEVER use arrow keys
| 
| I have just ordered the Informix-SQL product, I will be interested in seeing
| if "sperform" works realiably or not.
+---------------

I would doubt it; the problem has existed since the old Informix product.
Then again, it's also in vi and many other programs that use both ESC and
function/arrow keys.

The problem is handling ESC-prefixed keys while also using a bare ESC as a
command; it's more Unix's fault, since a timeout is required and Unix alarm
timeouts just aren't very reliable.  Unify under System III/V came up with a
better solution, and I believe System V curses has adopted it as well:  if
function keys are being used, set the packet size (VMIN) to the length of
the longest function key sequence with a packet timeout depending on the
baud rate and packet length.  It works well, if the packet code in the
driver is correct.  (I've used systems where the console driver mishandled
packet sizes other than 1, and the function and arrow keys NEVER worked.)
Unfortunately, it's dependent on the System III/V tty driver's packet
(-icanon) mode, and it can't be done with a V7 or BSD tty driver as far as I
know.

++Brandon
-- 
Brandon S. Allbery, uunet!marque!ncoast!allbery			DELPHI: ALLBERY
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