Experimental Physics and
Industrial Control System

Benjamin Franksen <[email protected]> · Fri, 29 Feb 2008 12:09:15 +0100

On Wednesday 27 February 2008 20:39, Tim Mooney wrote:
> Benjamin Franksen wrote:
> > On Friday 22 February 2008 20:08, Tim Mooney wrote:
> >> (Note the above file must end with '\n' or "\r\n".)
> >
> > Hi,
> >
> > is there a rationale behind this? If not, I think this should be fixed.
> >
> > Similar remarks apply, BTW, to other EPICS tools. For instance, I
> > noticed in the past that dbExpand silently ignores the last line of a
> > dbd include file if it doesn't end in a newline. This has caused
> > endless grief to Windows users, as editors for Windows generally don't
> > automatically add a newline at the end.
> >
> > If this hasn't already been fixed, I propose to put it on the list of
> > things to be done before the next release of base. I'd say chances that
> > people rely on the faulty behaviour are practically zero.
>
> This is not a problem in base.  Autosave simply needs to know that the
> file it's restoring from was not corrupted by an ioc crash that occurred
> while the file was being written.  The simplest and most common artifact
> of such a crash is a truncated file, and autosave detects this by
> requiring the last few characters of the file to fit a pattern that is
> unlikely to occur in the middle of the file, and by always ending the
> files it writes in this way.  Some systems use "\r\n" as an end-of-record
> character, and some use "\n", so both are permitted.
>
> Autosave was not intended to process files written by humans.  

This sounds like a perfect rationale to me. Thanks for explaining.

> If this 
> use becomes common enough, it will be worthwhile to code a relaxed reader
> that recognizes files written by humans, and doesn't require any special
> end pattern.

(I'd rather see db file format & tools extended to support arrays.)

Cheers
Ben
-- 
"Programming = Mathematics + Murphy's Law" (E.W.Dijkstra)

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System