CLASS VALUE_SEMANT(3)

NAME
boost::program_options::value_semantic

SYNOPSIS

// In header: <boost/program_options/value_semantic.hpp>
class value_semantic {
public:
  // construct/copy/destruct
  ~value_semantic();
  // public member functions
  std::string name() const;
  unsigned min_tokens() const;
  unsigned max_tokens() const;
  bool is_composing() const;
  bool is_required() const;
  void parse(boost::any &, const std::vector< std::string > &, bool) const;
  bool apply_default(boost::any &) const;
  void notify(const boost::any &) const;
};

DESCRIPTION

Class which specifies how the option's value is to be parsed and converted into C++ types.

  value_semantic public construct/copy/destruct

    1.

    ~value_semantic();

  value_semantic 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 parse(boost::any & value_store,
               const std::vector< std::string > & new_tokens, bool utf8) const;

    Parses a group of tokens that specify a value of option. Stores the result in 'value_store', using whatever representation is desired. May be be called several times if value of the same option is specified more than once.

    7.

    bool apply_default(boost::any & value_store) const;

    Called to assign default value to 'value_store'. Returns true if default value is assigned, and false if no default value exists.

    8.

    void notify(const boost::any & value_store) const;

    Called when final value of an option is determined.