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pointer_to_unary_function

Converts a unary function pointer into an adaptable unary function.

template<class Arg, class Result>
class pointer_to_unary_function
   : public unary_function<Arg, Result> 
   {
   public:
      explicit pointer_to_unary_function(Result (
         _*pfunc)(Arg)
      );
      Result operator()(
         const Arg _Left
      ) const;
   };

Parameter

_*pfunc
The binary function to be converted.
_Left
The object that the *pfunc is called on.

Return Value

The template class stores a copy of pfunc. It defines its member function operator() as returning (*pfunc)(_Left).

Remarks

A unary function pointer is a function object and may be passed to any Standard Template Library algorithm that is expecting a unary function as a parameter, but it is not adaptable. To use it with an adaptor, such as binding a value to it or using it with a negator, it must be supplied with the nested types argument_type and result_type that make such an adaptation possible. The conversion by pointer_to_unary_function allows the function adaptors to work with binary function pointers.

Example

The constructor of pointer_to_unary_function is rarely used directly. See the helper function ptr_fun for an example of how to declare and use the pointer_to_unary_function adaptor predicate.

See Also

<functional> Members

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