Subject: Re: RFC: getopt_long(3) change
To: None <tech-userlevel@NetBSD.org>
From: Brian Ginsbach <ginsbach@NetBSD.org>
Date: 06/26/2007 21:18:06
On Sat, Jun 23, 2007 at 09:05:11AM +0200, Alan Barrett wrote:
> On Fri, 22 Jun 2007, Brian Ginsbach wrote:
> > The long options are set so that both "color" and "colour" would
> > be supported and both return the same value when parsed. There
> > are no other long options that start with "col".
> > A command is passed the option --col. The current version of NetBSD
> > getopt_long(3) treats this as an ambiguous argument. This was the
> > behavior of GNU getopt_long(3) for GNU C library 2.1.3. Later
> > versions of the GNU C library doesn't treat this as ambiguous.
> Thank you. So the fix is something like "if it looks like an ambiguous
> abbreviation of two or more long options, but all the possible
> interpretations would return the same value, then just return that value
> without complaining that it's ambiguous." This seems sensible.
Yes. I believe this is exactly why the GNU developers made this same
change long ago. To do otherwise seems to violate POLA.
> > The change also fixes the handling of single character options that
> > are both a long option and a short option and there are options
> > that start with the same character. Note the long option parses
> > to a different value than the short option.
> And here, I assume the fix is "if it could be interpreted either as an
> exact match for one long option, or as an abbreviation for one or more
> other long options, then treat it as the exact match." This too seems
Yes, I believe that this accurately describes the situation. I did all
of this over a year ago. I think I'm describing the situation accurately.
> Please update the man page, which currently doesn't say anything about
This is definitely a bug. Even the current code, w/o the proposed change,
will support abbreviations! I'll work on adding something similar to what
The getopt_long() function works like getopt() except that
it also accepts long options, started out by two dashes.
**** Long option names may be abbreviated if the abbreviation ****
**** is unique or is an exact match for some defined option. A ****
long option may take a parameter, of the form --arg=param
or --arg param.
Any suggestions on wording or where to add to the current man page
would be greatly appreciated.
> --apb (Alan Barrett)