Re: A basic question on encoding Latin characters

From: Paul Keinanen (keinanen@sci.fi)
Date: Wed Sep 29 1999 - 16:12:15 EDT


On Wed, 29 Sep 1999 09:56:30 -0700 (PDT), Rick McGowan
<rmcgowan@apple.com> wrote:

>Paul Keinanen wrote:
>
>> The only solution I can think to the original problem with prompts is
>> to a add a dummy character (such as U+0000 or U+FEFF) that can not be
>> followed by combining marks at the end of the prompt string.
>
>No need to add a dummy character, just pick some control character or even
>some odd-ball punctuation; in the particular protocol, specify that (unless
>escaped) it cannot be a charaacter of the data stream, and use it.

It is very dangerous to pick an arbitrary control character. The NUL
(U+0000) is the only safe selection, since it was originally intended
as a time fill. I guess suggesting using NUL as the terminating
character would create protests among C users, but in fact it would be
quite easy to output a null-terminated string by simply specifying one
more character to be outputted than what is returned by the wstrlen
function :-).

The terminal would have to send the NUL character after each normal or
combining character entered on the keyboard and the remote echo would
have to also echo back this NUL character. However, the terminal
driver would have to strip off the NULL before returning the character
or combined character back to the application.

Paul



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