Re: [Boost-users] program options: unrecognized command-line options

Subject: Re: [Boost-users] program options: unrecognized command-line options
From: Peter Bartlett (pete_at_[hidden])
Date: 2009-01-15 05:11:04

Quoting Deane Yang <deane.yang_at_[hidden]>:

> Christoph Duelli wrote:
>> Deane Yang wrote:
>>
>>> I'm using the program options library to parse both command-line and
>>> configuration file parameters. I'd like to know how to find command-line
>>> arguments that are *not* registered and therefore not recognized by the
>>> parser. I want to be able to print a warning message like "Following
>>> arguments were ignored:....".
>>
>> I did it like that:
>>
>> // assume that options is a std::vector<std::string> containing
>> // the passed options (argv[])
>> po::options_description desc; // contains the options your prog supports
>>
>>
>> po::variables_map vm;
>> po::command_line_parser parser(options).allow_unregistered().options(desc);
>>
>> po::parsed_options parsed = parser.run();
>> po::store(parsed, vm);
>> po::notify(vm); // recognized options
>>
>> std::vector<std::string> unrecognizedOptions =
>>   po::collect_unrecognized(parsed.options, po::include_positional);
>>
>>
>> This is documented at
>> doc/html/program_options/howto.html#id3458178 in your Boost docs.
>>
>
> Thanks. I did see this, but was hoping for something more graceful. I
> find it ironic that to disallow unregistered options, I have to use the
> function allow_unregistered. Shouldn't the opposite of
> "allow_unregistered" be a state where unregistered options are
> forbidden?

That's perhaps a little unfair as the library by default throws an  
exception on discovering unregistered options. Is it the case that you  
are just looking for a better exception message?