CTRL(x) macro (was: Re: What is a constant expression)

[Norman Diamond]

In article <3802 at solo7.cs.vu.nl> maart at cs.vu.nl (Maarten Litmaath) writes:

>In BSD the new tty driver as well as vi, cat -v, ... use ^? to denote DEL.
>Seems pretty normal to me.  According to iscntrl(3) DEL is a control character
>too.

It also seems reasonable to me to think of DEL as a control character.
However, it does seem to be ambiguous in the industry.  That is why
some manuals refer to "control characters and DEL" in order to avoid
ambiguity.

>Too bad it isn't a normal control character; it would have simplified
>things.

Well, it couldn't possibly be a normal control character.  To delete a
typographical error from paper tape, you had to backspace the tape and
punch all 1's (holes) in that column.  If someone decided to make DEL
something other than all 1's, then they would have to invent another
delete that would be all 1's, and it would STILL be ambiguous if the
new delete was really a control character or not.

-- 
Norman Diamond, Sony Corp. (diamond%ws.sony.junet at uunet.uu.net seems to work)
  Should the preceding opinions be caught or     |  James Bond asked his
  killed, the sender will disavow all knowledge  |  ATT rep for a source
  of their activities or whereabouts.            |  licence to "kill".