CODEWITHSUNDEEP
c++boostboost-program-options
marcman
marcman

Reputation: 3393

Boost::program_options - print usage if no inputs provided

I am trying to use Boost program_options in order to parse my program inputs. In general the docs provide the necessary info for parsing. However, I would like to make my program print the usage instructions when no inputs are provided and I can't seem to figure it out. There does not seem to be a "default" options nor can I find how to count the number of inputs provided (to test).

This is my code at the moment:

boost::program_options::options_description help("Usage");
help.add_options()
    ("help", "print help info");

boost::program_options::options_description req("Required inputs");
req.add_options()
    ("root", boost::program_options::value<std::string>(&images_root), "Root directory")

boost::program_options::options_description opt("Option inputs");
opt.add_options()
    ("verbose", boost::program_options::value<bool>(&verbose)->implicit_value(1), "Verbose");

boost::program_options::variables_map vm;
boost::program_options::store(boost::program_options::parse_command_line(argc, argv, all), vm);
if (vm.count("help"))
{
    std::cout << help;
    return 1;
}

boost::program_options::notify(vm);

How can I produce the following (i.e. if no inputs do std::cout << help)?

./test-file
>> print help info

Upvotes: 2

Views: 1399

Answers (1)

Roby
Roby

Reputation: 2061

You could do it with argc

for example:

int main(int argc, char** argv)
{
    if( argc <= 1 )
      std::cout << "Print Usage\n";

  return 0;
}

Upvotes: 1

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