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## Class template typed_value

boost::program_options::typed_value —

## Synopsis

    template<typename T, typename charT = char>
    class typed_value
      :  : public boost::program_options::value_semantic_codecvt_helper< charT >
    {
    public:
      // construct/copy/destruct
      typed_value(T *);

      // public member functions
      typed_value * default_value(const T &) ;
      typed_value * default_value(const T &, const std::string &) ;
      typed_value * notifier(function1< void, const T & >) ;
      typed_value * composing() ;
      typed_value * multitoken() ;
      typed_value * zero_tokens() ;
      std::string name() const;
      bool is_composing() const;
      unsigned min_tokens() const;
      unsigned max_tokens() const;
      void xparse(boost::any &, const std::vector< std::basic_string< charT > > &) const;
      virtual bool apply_default(boost::any &) const;
      void notify(const boost::any &) const;
    };

## Description

Class which handles value of a specific type.

### `typed_value` construct/copy/destruct

1.     typed_value(T * store_to);

   Ctor. The 'store_to' parameter tells where to store the value when it's known. The parameter can be NULL.

### `typed_value` public member functions

1.     typed_value * default_value(const T & v) ;

   Specifies default value, which will be used if none is explicitly specified. The type 'T' should provide operator<< for ostream.

2.     typed_value * default_value(const T & v, const std::string & textual) ;

   Specifies default value, which will be used if none is explicitly specified. Unlike the above overload, the type 'T' need not provide operator<< for ostream, but textual representation of default value must be provided by the user.

3.     typed_value * notifier(function1< void, const T & > f) ;

   Specifies a function to be called when the final value is determined.

4.     typed_value * composing() ;

   Specifies that the value is composing. See the 'is_composing' method for explanation.

5.     typed_value * multitoken() ;

   Specifies that the value can span multiple tokens.

6.     typed_value * zero_tokens() ;

7.     std::string name() const;

8.     bool is_composing() const;

9.     unsigned min_tokens() const;

10.     unsigned max_tokens() const;

11.     void xparse(boost::any & value_store,
                    const std::vector< std::basic_string< charT > > & new_tokens) const;

    Creates an instance of the 'validator' class and calls its operator() to perform athe ctual conversion.

12.     virtual bool apply_default(boost::any & value_store) const;

    If default value was specified via previous call to 'default_value', stores that value into 'value_store'. Returns true if default value was stored.

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

    If an address of variable to store value was specified when creating *this, stores the value there. Otherwise, does nothing.

| Copyright © 2002-2004 Vladimir Prus