Re: XPL is smarter than we are

[cld@xxxxxxxx (Carl Distefano)]

Reply to note from Harry Binswanger  Mon, 03 Jan 2005
21:14:13 -0500

> Earlier I asked about how to re-set the error flag.

Oh, so that's what you were talking about: how to reset  to FALSE
(no error). I thought you were asking about setting  to 0. Not
the same thing.

Well, as you discovered, the way to reset  is to issue a command --
any command -- that succeeds. The fact that an immediately preceding
command failed is irrelevant;  won't be tricked into reporting a
false error. The ror state always refers to the last-executed
command. For this reason it's rarely if ever necessary to "reset the
error flag". Nevertheless, one command that does so reliably, every
time, is BX waitQ2 . WAIT always succeeds. And, in most contexts, it
executes instantaneously -- because ninety-nine times out of a hundred
there's nothing for it to wait for.

--
Carl Distefano
cld@xxxxxxxx