Re: [Boost-users] Command Line Options Questions

Take a look at the following docs for the validate function:

http://www.boost.org/doc/libs/1_60_0/doc/html/program_options/howto.html#idm... On 03/07/2016 02:32 PM, Jon Lederman wrote:

Hi,

I tried like this:

std::ostream& operator<<(std::ostream& os, const dsp_type& obj) { // write obj to stream os << obj.value; return os; } std::istream& operator>>(std::istream& is, dsp_type& obj) { // read obj from stream if ( 0 /* T could not be constructed */ ) is.setstate(std::ios::failbit); is >> obj.value; return is;

}

However now it let’s everything through and doesn’t validate. What is the proper way to do this?

-Jon

...

On Mar 6, 2016, at 3:50 PM, Daniel Hofmann wrote:

You have to implement operator<< otherwise the compiler does not know how to print (pipe it into an ostream) dsp_type.

You can use Boost.Fusion's I/O feature and BOOST_ADAPT_STRUCT like this

...

https://github.com/daniel-j-h/argparse-generic/blob/master/example.cc to make your life easier.

On March 6, 2016 5:43:27 PM GMT+01:00, Jon Lederman wrote:

...

Hi,

I have two questions re: the boost command line options library:

1) I am compiling a dynamic library that links to the boost command line options library as a shared library. When I try to unload the dynamic library, I find that it isn’t properly unloaded and the boost library seems to be causing the issue. I did find that things were helped somewhat when I linked to the boost static libraries. However, it still feels unstable. Are there any particular things I should know about in this context in terms of how my makefile should be linking to boost? Or are there other things I should look at.

2) When using program options, I am getting the following error. For some reason this seemed to work with the dynamic libraries (or it may be a coincidence). Am I required to implement the << and >> operators? It had been compiling previously and stopped. After googling this issue there seems to be a lot of confusion. Any help would be greatly appreciated.

in file included from /usr/include/boost/any.hpp:27:0, from /usr/include/boost/program_options/value_semantic.hpp:12, from /usr/include/boost/program_options/options_description.hpp:13, from /usr/include/boost/program_options.hpp:15, from /usr/local/src/freeswitch/src/mod/applications/mod_sc_dsp/mod_sc_dsp.cpp:23: /usr/include/boost/lexical_cast.hpp: In instantiation of 'struct boost::detail::deduce_target_char_impl

...

': /usr/include/boost/lexical_cast.hpp:415:89: required from 'struct boost::detail::deduce_target_char' /usr/include/boost/lexical_cast.hpp:674:92: required from 'struct boost::detail::lexical_cast_stream_traits' /usr/include/boost/lexical_cast.hpp:2363:19: required from 'static Target boost::detail::lexical_cast_do_cast::lexical_cast_impl(const Source&) [with Target = dsp_type; Source = std::basic_string<char>]' /usr/include/boost/lexical_cast.hpp:2543:50: required from 'Target boost::lexical_cast(const Source&) [with Target = dsp_type; Source = std::basic_string<char>]' /usr/include/boost/program_options/detail/value_semantic.hpp:89:38: required from 'void boost::program_options::validate(boost::any&, const std::vector&, T*, long int) [with T = dsp_type; charT = char]' /usr/include/boost/program_options/detail/value_semantic.hpp:170:55: required from 'void boost::program_options::typed_value::xparse(boost::any&, const std::vector, T >::value),

desc.add_options() ("help", "Generates help message") ("dsp_type", po::value(¶ms.dsp_type)->required(), “")

where dsp_type is this:

struct dsp_type { dsp_type() {} dsp_type(std::string const& val): value(val) { }

std::string value; };

and I have a validator defined as this:

void validate(boost::any& v, std::vectorstd::string const& values, dsp_type* /* target_type */, int) { using namespace boost::program_options; //namespace po = boost::program_options;

// Make sure no previous assignment to 'v' was made. validators::check_first_occurrence(v);

// Extract the first string from 'values'. If there is more than // one string, it's an error, and exception will be thrown. std::string const& s = validators::get_single_string(values);

if (s == "ladspa" || s == "audioweaver" || s == "gstreamer" || s == "lv2") { v = boost::any(dsp_type(s)); } else { throw validation_error(validation_error::invalid_option_value); } }

/usr/local/src/freeswitch/build/modmake.rules:214: recipe for target 'mod_sc_dsp.lo' failed make[1]: *** [mod_sc_dsp.lo] Error 1

------------------------------------------------------------------------

_______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users