Single-token and multi-token positional options with boost::program_options

Question

I am writing a program that would receive as parameters a filename followed by multiple strings. Optionally it could take a -count argument;

./program [-count n] <filename> <string1> <string2> ...

This is the code I wrote:

    PO::positional_options_description l_positionalOptions;
    l_positionalOptions.add("file", 1);
    l_positionalOptions.add("strings", -1);

    PO::options_description l_optionsDescription;
    l_optionsDescription.add_options()
        ("count", PO::value<int>()->default_value(1), "How many times to write"),
        ("file", PO::value<std::string>(), "Output file name"),
        ("strings", PO::value<std::vector<std::string>>()->multitoken()->zero_tokens()->composing(), "Strings to be written to the file");

    PO::command_line_parser l_parser {argc, argv};
    l_parser.options(l_optionsDescription)
            .positional(l_positionalOptions)
            .allow_unregistered();

    PO::variables_map l_userOptions;

    try {
        PO::store(l_parser.run(), l_userOptions);
    }
    catch (std::exception &ex) {
        std::cerr << ex.what() << std::endl;
        exit(1);
    }

However, when I run ./program file.out str1 str2 str3 it fails with:

unrecognised option 'str1'

What am I doing wrong? Is this even possible with boost::program_options?

Answer 1

I figured it out. It's as dumb as it can get.

The issue was that I had a , after every entry in add_options(). This made it so only the first entry would get saved.