Hello, I've just started using boost. I'm making use of the program_options to take arguments for my tool. I've written the following:
mDesc.add_options() ("help,h", "Print this usage message.") ... .... .. ("v-level,v",boost::program_options::value<int>(&mVerboseLevel),"Debug level: 1,2,3\n(default: 0)") ("version",boost::program_options::value<std::string>()->zero_tokens(),"Package information: version etc.")
and then, I have a method, which I call in main(int argc, char **argv):
/* *-------------------------------------------------------------------------------------- * Class: Session * Method: Session :: ParseCommandLine * Description: Parse the command line *-------------------------------------------------------------------------------------- */ int Session::ParseCommandLine (int argc, char **argv) { boost::program_options::store(boost::program_options::parse_command_line(argc, argv, mDesc), mVariableMap); /* notify required to save the values into my variables. */ /* TODO: confirm this behaviour */ boost::program_options::notify(mVariableMap);
if (mVariableMap.count("help")) { std::cout << mDesc << std::endl; return -1; } return 0; } /* ----- end of method Session::ParseCommandLine ----- */
However, when I invoke my tool, I get an exception (which I admit I haven't handled yet):
[ankur@ankur dump]$ ./src/test --version terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::program_options::validation_error> >' what(): in option 'version': at least one value required Aborted (core dumped) [ankur@ankur dump]$
I'm referring this document[1] which says that zero_tokens() implies an argument may or may not be provided. Why is the exception coming up saying I need "at least one value"? What am I missing? Another query: is notify() necessary to save the values provided on the command line to the variables I pass in the add_options() from the variable map (to mVerboseLevel for instance)? [1] http://www.boost.org/doc/libs/1_42_0/doc/html/program_options/overview.html -- Thanks, Regards, Ankur: "FranciscoD" http://fedoraproject.org/wiki/User:Ankursinha http://dodoincfedora.wordpress.com/