How to use boost::program_options to accept an optional flag?
A convenient way to do this is with the bool_switch
functionality:
bool flag = false;
namespace po = boost::program_options;
po::options_description desc("options");
desc.add_options()
("flag,f", po::bool_switch(&flag), "description");
po::variables_map vm;
//store & notify
if (flag) {
// do stuff
}
This is safer than manually checking for the string (string only used once in whole definition).
Use it as usual but without any value:
boost::program_options::options_description od("allowed options");
od.add_options()
("flag,f", "description");
po::variables_map vm;
// store/ notify vm
if (vm.count("flag")) {
// flag is set
}
See the Getting Started option help as an example.