Boost C++ Libraries of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is the documentation for an old version of Boost. Click here to view this page for the latest version.

Class untyped_value



// In header: <boost/program_options/value_semantic.hpp>

class untyped_value :
  public boost::program_options::value_semantic_codecvt_helper< char >
  // construct/copy/destruct
  untyped_value(bool = false);

  // public member functions
  std::string name() const;
  unsigned min_tokens() const;
  unsigned max_tokens() const;
  bool is_composing() const;
  bool is_required() const;
  void xparse(boost::any &, const std::vector< std::string > &) const;
  bool apply_default(boost::any &) const;
  void notify(const boost::any &) const;


Class which specifies a simple handling of a value: the value will have string type and only one token is allowed.

untyped_value public construct/copy/destruct

  1. untyped_value(bool zero_tokens = false);

untyped_value public member functions

  1. std::string name() const;

    Returns the name of the option. The name is only meaningful for automatic help message.

  2. unsigned min_tokens() const;

    The minimum number of tokens for this option that should be present on the command line.

  3. unsigned max_tokens() const;

    The maximum number of tokens for this option that should be present on the command line.

  4. bool is_composing() const;

    Returns true if values from different sources should be composed. Otherwise, value from the first source is used and values from other sources are discarded.

  5. bool is_required() const;

    Returns true if value must be given. Non-optional value

  6. void xparse(boost::any & value_store, 
                const std::vector< std::string > & new_tokens) const;

    If 'value_store' is already initialized, or new_tokens has more than one elements, throws. Otherwise, assigns the first string from 'new_tokens' to 'value_store', without any modifications.

  7. bool apply_default(boost::any &) const;

    Does nothing.

  8. void notify(const boost::any &) const;

    Does nothing.