Boost：位置参数无法识别的选项

Question

我正在尝试使用 boost 1.58.0 解析命令行。我的代码非常简单，来自教程 copy\pasted。看起来像这样：

 try {
        po::options_description desc;
        desc.add_options()
                ("version,v", "Display version of application.");

        po::positional_options_description p;
        p.add("input-file", -1);

        try
        {
            po::store(po::command_line_parser(argc, argv).
                      options(desc).positional(p).run(), vm);

            if ( vm.count("version")  )
            {
                std::cout << "Program version: " << SHUF_T_VERSION << std::endl << "Boost library version: " << BOOST_LIB_VERSION << std::endl;
                return false;
            }

            po::notify(vm); // throws on error, so do after help in case
            // there are any problems
        }
        catch(po::error& e)
        {
            std::cerr << "ERROR: " << e.what() << std::endl << std::endl;
            std::cerr << desc << std::endl;
            return false;
        }

    }
    catch(std::exception& e)
    {
        std::cerr << "Unhandled Exception: "
                  << e.what() << ", application will now exit" << std::endl;
        return false;

    }

  return true;

整个代码是here。代码似乎是正确的。 app -v 处理正确。但是如果我包含任何位置争论，比如 app myfile，po::store() 就会抛出 unrecognised option 'myfile'。关于为什么会发生这种情况有什么想法吗？

Answer 1

您需要添加 "input-file" 作为选项：

po::options_description desc;
desc.add_options()
        ("version,v", "Display version of application.")
        ("input-file", po::value<std::vector<std::string> >(), "input file");

来自the tutorial：

The "input-file" option specifies the list of files to process. That's okay for a start, but, of course, writing something like:
compiler --input-file=a.cpp
is a little non-standard, compared with
compiler a.cpp
We'll address this in a moment.

The command line tokens which have no option name, as above, are called "positional options" by this library. They can be handled too. With a little help from the user, the library can decide that "a.cpp" really means the same as "--input-file=a.cpp". Here's the additional code we need:
po::positional_options_description p;
p.add("input-file", -1);

po::variables_map vm;
po::store(po::command_line_parser(ac, av).
          options(desc).positional(p).run(), vm);
po::notify(vm);

Boost：位置参数无法识别的选项

Boost: unrecognised option for positional argument

c++

boost

boost-program-options