Re: [Boost-users] Unicode option in program_options

John Dlugosz wrote:

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see reference to class template instantiation 'boost::program_options::typed_value' being compiled with [ T=std::wstring, charT=char ]

You should consider po::wvalue<> template function.

Thanks Mickaël, that is better.

So, why does po::value<T> work for whatever type I want my parameter to be

Not really -- it works for whatever type you can extract out of stringstream, not whatever type.

_except_ for wstring,

and wstring cannot be extracted from stringstream.

which needs to use po::wvalue<T> instead?

("datadir", po::wvaluestd::wstring()->default_value(std::wstring(L"."),"."), "the directory")

Now getting default_value to work with that was some trial and error. It didn't take L".", which is exactly what parse_command_line is going to be finding were it not the default. I would expect a token in either wide or narrow forms to work, and give the same results as those tokens would if found in the argv array.

default_value is another victim of the fact that wstring cannot be converted to string. I am not sure much can be done on program_options side. - Volodya