crash with one dash

please see attached GIF demonstrate crash with one dash i.e. to wit if an option is introduced w/ one dash instead of two exception is thrown . below is code executed .
```
#include
#include
#include
using namespace std;

const string option_flag = "O";
const string option_flag_description = string("an option");

const map options__description_map = {
{option_flag, option_flag_description},
};

int main(int argc, const char* argv[], const char* envp[])
{
boost::program_options::variables_map vm;
string macros;
boost::program_options::options_description options_description("bugyCode options");
options_description.add_options()
(option_flag.c_str(), boost::program_options::value(¯os), option_flag_description.c_str());

boost::program_options::store(boost::program_options::parse_command_line(argc, argv, options_description), vm);
boost::program_options::notify(vm);
return 0;
}
```