[Boost-users] [program_options] is a more complicated usage supported?

Subject: [Boost-users] [program_options] is a more complicated usage supported?
From: Stephan Menzel (stephan.menzel_at_[hidden])
Date: 2008-12-02 04:09:47

Hi there,

I'm using program_options on 1.36, quite successfully so far with only simple use cases.
However, now I have to do something a little more tricky. Essentially, I'd like to parse everything before a certain point and treat everything after that as positional_options. Goal is to have a variable command line that can take arbitary commands, much in the fashion tools such as valgrind and strace would.

Consider this:

./mytool --myopt 1 --anotheropt bla ./someapp --appoption 1

So mytool would need to parse it's own options 'myopt' and 'anotheropt' and then be aware of the string './someapp --appoption 1' to eventually fork whatever is there. And to make it a little more interesting some of the options should be optional.

Alas, docs don't really get into that so I'm wondering if/how this could be done. This is what I got:

po::options_description desc("Allowed options, after that state the desired command");
desc.add_options()
  ("anotheropt,a", po::value<std::string>(), "some other option")
  ("myopt,o", po::value<boost::uint16_t>()->default_value(1), "optional value 1")
;

po::variables_map vmap;
po::store(po::parse_command_line(argc, argv, desc), vmap);
po::notify(vmap);

// at this point I got my options.

po::positional_options_description pd;
pd.add("command", -1);

po::parsed_options parsed = po::command_line_parser(argc, argv).options(desc).allow_unregistered().run();
std::vector<std::string> command_options = collect_unrecognized(parsed.options, po::include_positional);

// here I got command_options filled with the unrecognized options.

...snip...

That works OK as long as my command line does not have any options starting with - or -- at it's own. As soon as the command to be forked has such options, the first po::store() would throw because it tries to parse them.
Is there any way to prevent this?

Thanks and greetings...

Stephan