Re: [Boost-users] [boost::program_options] optional arguments

From: Bryan Green (bgreen_at_[hidden])
Date: 2007-06-13 13:34:15

"Chris Weed" writes:
> I am at a loss of how to do that.
> Hopefully someone else can give you a hand.
> Chris
> 
> On 6/12/07, Bryan Green <bgreen_at_[hidden]> wrote:
> > "Chris Weed" writes:
> > > On 6/12/07, Bryan Green <bgreen_at_[hidden]> wrote:
> > > > Hello,
> > > >
> > > > Is there a mechanism in boost::program_options for supporting optional
> > > > arguments?  If not, is there a suggested program_options-based alternat
> ive?
> > > >
> > >
> > > What exactly do you mean by optional arguments?
> > > Do you mean like this?
> > > http://www.boost.org/doc/html/program_options/howto.html#id1593176
> > >
> > > Chris
> >
> > The quotation in my email goes into exact detail - basically, I'm looking
> > for functionality equivalent to GNU getopt_long, which has an
> > "optional_argument" specifier.  It is a method for optionally associating a
> > value with a particular option.
> > For example, if I specify a getopt_long parameter to enable listening on a
> > socket:
> >
> >  {"listen",optional_argument,NULL,'l'}
> >
> > Then, on the command line,
> >  '--listen' means to enable listening, using a default port number.
> >  '--listen=5000' means enable listening, using port number 5000.
> >
> > The only way I see to accomplish this with program_options is to make a
> > second option called "listen_port".

I've discovered that this does not work either, because if you try to
specify the '--listen' option, it complains that it is ambiguous.

Is there any more information on how the 'zero_tokens' flag is supposed to
behave for non-boolean types?

-Bryan