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## Class template visitor_ptr_t

boost::visitor_ptr_t — Adapts a function pointer for use as a static visitor.

## Synopsis

    template<typename T, typename R>
    class visitor_ptr_t : public static_visitor<R> {
    public:
      // construct/copy/destruct
      explicit visitor_ptr_t(R (*)(T));

      // static visitor interfaces
      R operator()(unspecified-forwarding-type);
      template<typename U> void operator()(const U&);
    };

## Description

Adapts the function given at construction for use as a static visitor of type `T` with result type `R`.

### `visitor_ptr_t` construct/copy/destruct

1.     explicit visitor_ptr_t(R (*)(T) );

   Effects: Constructs the visitor with the given function.

### `visitor_ptr_t` static visitor interfaces

1.     R operator()(unspecified-forwarding-type operand);
       template<typename U> void operator()(const U& );

   Effects: If passed a value or reference of type `T`, it invokes the function given at construction, appropriately forwarding `operand`.
   Returns: Returns the result of the function invocation.
   Throws: The overload taking a value or reference of type `T` throws if the invoked function throws. The overload taking all other values always throws `bad_visit`.

| Copyright © 2002, 2003 Eric Friedman, Itay Maman