      ______________________________________________________________________

      20   General utilities library                         [lib.utilities]

      ______________________________________________________________________

    1 This clause describes components used by other elements of  the  Stan-
      dard  C++ library.  These components may also be used by C++ programs.

    2 The following clauses describe  utility  and  allocator  requirements,
      utility components, function objects, dynamic memory management utili-
      ties, and date/time utilities, as summarized in Table 1:

                    Table 1--General utilities library summary

             +-------------------------------------------------------+
             |                Clause                     Header(s)   |
             +-------------------------------------------------------+
             |_lib.utility.requirements_ Requirements                |
             +-------------------------------------------------------+
             |_lib.utility_ Utility components          <utility>    |
             +-------------------------------------------------------+
             |_lib.function.objects_ Function objects   <functional> |
             +-------------------------------------------------------+
             |_lib.memory_ Memory                       <memory>     |
             +-------------------------------------------------------+
             |_lib.date.time_ Date and time             <ctime>      |
             +-------------------------------------------------------+

      20.1  Requirements                          [lib.utility.requirements]

    1 Clause _lib.utility.requirements_ describes requirements  on  template
      arguments.   Clauses  _lib.equalitycomparable_  through  _lib.copycon-
      structible_ describe requirements on types used  to  instantiate  tem-
      plates.   Clause  _lib.allocator.requirements_  describes the require-
      ments on storage allocators.

      20.1.1  Equality comparison                   [lib.equalitycomparable]

    1 In Table 2, T is a type to be supplied by a C++ program  instantiating
      a template, a, b and c are values of type T.

                     Table 2--EqualityComparable requirements

      +------------------------------------------------------------------------+
      |expression       return type                   requirement              |
      +------------------------------------------------------------------------+
      |a == b       convertible to bool   ==  is an equiva-                    |
      |                                   lence   relation,                    |
      |                                   that  is, it sat-                    |
      |                                   isfies  the  fol-                    |
      |                                   lowing    proper-                    |
      |                                   ties:                                |
      |                                                                        |
      |                                   --For all a, a == a.                 |
      |                                                                        |
      |                                   --If a == b, then b == a.            |
      |                                                                        |
      |                                   --If a == b and b == a, then a == c. |
      +------------------------------------------------------------------------+

      20.1.2  Less than comparison                  [lib.lessthancomparable]

    1 In the following Table 3, T is a type to be supplied by a C++  program
      instantiating a template, a and b are values of type T.

                     Table 3--LessThanComparable requirements

      +--------------------------------------------------------------------------------------------+
      |expression       return type                             requirement                        |
      +--------------------------------------------------------------------------------------------+
      |a < b        convertible to bool   < is a strict weak ordering relation (_lib.alg.sorting_) |
      +--------------------------------------------------------------------------------------------+

      20.1.3  Copy construction                      [lib.copyconstructible]

    1 In  the following Table 4, T is a type to be supplied by a C++ program
      instantiating a template, t is a value of type T, and u is a value  of
      type const T.

                     Table 4--CopyConstructible requirements

              +----------------------------------------------------+
              |expression   return type         requirement        |
              +----------------------------------------------------+
              |T(t)                       t is equivalent to T(t)  |
              +----------------------------------------------------+
              |T(u)                       u is equivalent to T(u)  |
              +----------------------------------------------------+
              |t.~T()                                              |
              +----------------------------------------------------+
              |&t           T*            denotes the address of t |
              +----------------------------------------------------+
              |&u           const T*      denotes the address of u |
              +----------------------------------------------------+

      20.1.4  Default construction                     [lib.default.con.req]

    1 The default constructor is not required.  Certain container class mem-
      ber function signatures specify the default constructor as  a  default
      argument.   T()  must be a well-defined expression (_dcl.init_) if one
      of  those  signatures   is   called   using   the   default   argument
      (_dcl.fct.default_).

      20.1.5  Allocator requirements            [lib.allocator.requirements]

    1 The  library  describes a standard set of requirements for allocators,
      which are objects that encapsulate the information about an allocation
      model.   This information includes the knowledge of pointer types, the
      type of their difference, the type of the  size  of  objects  in  this
      allocation  model,  as  well as the memory allocation and deallocation
      primitives for it.   All  of  the  containers  (_lib.containers_)  are
      parameterized in terms of allocators.

    2 Table  5 describes the requirements on types manipulated through allo-
      cators.  All the operations on the allocators are expected to be amor-
      tized  constant time.  Table 6 describes the requirements on allocator
      types.

                    Table 5--Descriptive variable definitions

         +---------------------------------------------------------------+
         |Variable                        Definition                     |
         +---------------------------------------------------------------+
         |T, U        any type                                           |
         +---------------------------------------------------------------+
         |X           an Allocator class for type T                      |
         +---------------------------------------------------------------+
         |Y           the corresponding Allocator class for type U       |
         +---------------------------------------------------------------+
         |t           a value of type const T&                           |
         +---------------------------------------------------------------+
         |a, a1, a2   values of type X&                                  |
         +---------------------------------------------------------------+
         |b           a value of type Y                                  |
         +---------------------------------------------------------------+
         |p           a value of type X::pointer, obtained by calling    |
         |            a1.allocate, where a1 == a.                        |
         +---------------------------------------------------------------+
         |q           a value of type X::const_pointer obtained by       |
         |            conversion from a value p.                         |
         +---------------------------------------------------------------+
         |r           a value of type X::reference obtained by           |
         |            the expression *p.                                 |
         +---------------------------------------------------------------+
         |s           a value of type X::const_reference obtained by     |
         |            the expression *q or by conversion from a value r. |
         +---------------------------------------------------------------+
         |u           a value of type Y::const_pointer obtained by       |
         |            calling Y::allocate, or else 0.                    |
         +---------------------------------------------------------------+
         |n           a value of type X::size_type.                      |
         +---------------------------------------------------------------+

                         Table 6--Allocator requirements

      -------------------------------------------------------------------------------------
                expression                 return type               assertion/note
                                                                   pre/post-condition
      -------------------------------------------------------------------------------------
       X::pointer                     Pointer to T.
      -------------------------------------------------------------------------------------
       X::const_pointer               Pointer to const T.
      -------------------------------------------------------------------------------------
       X::reference                   T&
      -------------------------------------------------------------------------------------
       X::const_reference             T const&
      -------------------------------------------------------------------------------------
       X::value_type                  Identical to T
      -------------------------------------------------------------------------------------
       X::size_type                   unsigned integral type   a type that can represent
                                                               the size of the largest
                                                               object in the allocation
                                                               model.
      -------------------------------------------------------------------------------------
       X::difference_type             signed integral type     a type that can represent
                                                               the difference between any
                                                               two pointers in the allo-
                                                               cation model.
      -------------------------------------------------------------------------------------
       typename X::rebind<U>::other   Y                        For all U (including T),
                                                               Y::rebind<T>::other is X.
      -------------------------------------------------------------------------------------
       a.address(r)                   X::pointer
      -------------------------------------------------------------------------------------
       a.address(s)                   X::const_pointer
      -------------------------------------------------------------------------------------
       a.allocate(n)                  X::pointer               Memory is allocated for n
       a.allocate(n,u)                                         objects of type T but ob-
                                                               jects are not constructed.
                                                               allocate may raise an ap-
                                                               propriate exception.  The
                                                               result is a random access
                                                               iterator.1)
      -------------------------------------------------------------------------------------
       a.deallocate(p, n)             (not used)               All n T objects in the
                                                               area pointed by p must be
                                                               destroyed prior to this
                                                               call.  n must match the
                                                               value passed to allocate
                                                               to obtain this memory.
                                                               [Note: p must not be null.
                                                                --end note]
      -------------------------------------------------------------------------------------

      |                                                                                   |
      |                                                                                   |
      |                                                                                   |
      |                                                                                   |
      |a.max_size()                   X::size_type             the largest value that can |
      |                                                        meaningfully be passed to  |
      |                                                        X::allocate().             |
      +-----------------------------------------------------------------------------------+
      |a1 == a2                       bool                     returns true iff storage   |
      |                                                        allocated from each can be |
      |                                                        deallocated via the other. |
      +-----------------------------------------------------------------------------------+
      |a1 != a2                       bool                     same as !(a1 == a2)        |
      +-----------------------------------------------------------------------------------+
      |X()                                                     creates a default in-      |
      |                                                        stance. Note: a destructor |
      |                                                        is assumed.                |
      +-----------------------------------------------------------------------------------+
      |X a(b);                                                 post: Y(a) == b            |
      +-----------------------------------------------------------------------------------+
      |x.construct(p,t)               (not used)               Effect: new((void*)p) T(t) |
      +-----------------------------------------------------------------------------------+
      |x.destroy(p)                   (not used)               Effect: ((T*)p)->~T()      |
      +-----------------------------------------------------------------------------------+

    3 The template class member rebind in the table above is  effectively  a
      template  typedef: if the name Allocator is bound to SomeAllocator<T>,
      then Allocator::rebind<U>::other is the same type as SomeAllocator<U>.

    4 Implementations of containers described in this International Standard
      are permitted to assume that their Allocator template parameter  meets
      the following two additional requirements beyond those in Table 6.

      --All  instances  of  a given allocator type are required to be inter-
        changeable and always compare equal to each other.

      --The typedef members pointer, const_pointer, size_type,  and  differ-
        ence_type  are  required  to be T*, T const*, size_t, and ptrdiff_t,
        respectively.

    5 Implementors are encouraged to supply libraries that can accept  allo-
      cators  that  encapsulate  more general memory models and that support
      non-equal  instances.   In  such  implementations,  any   requirements
      imposed  on  allocators  by  containers beyond those requirements that
      appear in Table 6, and the semantics of containers and algorithms when
      allocator instances compare non-equal, are implementation-defined.

      20.2  Utility components                                 [lib.utility]

    1 This  clause  contains  some basic template functions and classes that
      are used throughout the rest of the library.

      Header <utility> synopsis
      _________________________
      1) It is intended that a::allocate be an efficient means of allocating
      a  single  object  of  type T, even when sizeof(T) is small.  That is,
      there is no need for a container to maintain its own ``free list''.

      namespace std {
      // clause _lib.operators_, operators:
        namespace rel_ops {
          template<class T> bool operator!=(const T&, const T&);
          template<class T> bool operator> (const T&, const T&);
          template<class T> bool operator<=(const T&, const T&);
          template<class T> bool operator>=(const T&, const T&);
        }
      // clause _lib.pairs_, pairs:
        template <class T1, class T2> struct pair;
        template <class T1, class T2>
          bool operator==(const pair<T1,T2>&, const pair<T1,T2>&);
        template <class T1, class T2>
          bool operator< (const pair<T1,T2>&, const pair<T1,T2>&);
        template <class T1, class T2>
          bool operator!=(const pair<T1,T2>&, const pair<T1,T2>&);
        template <class T1, class T2>
          bool operator> (const pair<T1,T2>&, const pair<T1,T2>&);
        template <class T1, class T2>
          bool operator>=(const pair<T1,T2>&, const pair<T1,T2>&);
        template <class T1, class T2>
          bool operator<=(const pair<T1,T2>&, const pair<T1,T2>&);
        template <class T1, class T2> pair<T1,T2> make_pair(const T1&, const T2&);
      }

      20.2.1  Operators                                      [lib.operators]

    1 To avoid redundant definitions of operator!=  out  of  operator==  and
      operators  >,  <=,  and  >= out of operator<, the library provides the
      following:

      template <class T> bool operator!=(const T& x, const T& y);

      Requires:
        Type T is EqualityComparable (_lib.equalitycomparable_).
      Returns:
        !(x == y).

      template <class T> bool operator>(const T& x, const T& y);

      Requires:
        Type T is LessThanComparable (_lib.lessthancomparable_).
      Returns:
        y < x.

      template <class T> bool operator<=(const T& x, const T& y);

      Requires:
        Type T is LessThanComparable (_lib.lessthancomparable_).
      Returns:
        !(y < x).

      template <class T> bool operator>=(const T& x, const T& y);

      Requires:
        Type T is LessThanComparable (_lib.lessthancomparable_).
      Returns:
        !(x < y).

    2 In this library, whenever a declaration is provided for an operator!=,
      operator>,  operator>=,  or operator<=, and requirements and semantics
      are not explicitly provided, the requirements  and  semantics  are  as
      specified in this clause.

      20.2.2  Pairs                                              [lib.pairs]

    1 The  library  provides  a  template for heterogeneous pairs of values.
      The library also provides a matching  template  function  to  simplify
      their construction.

      template <class T1, class T2>
      struct pair {
        typedef T1 first_type;
        typedef T2 second_type;

        T1 first;
        T2 second;
        pair();
        pair(const T1& x, const T2& y);
        template<class U, class V> pair(const pair<U, V> &p);
      };

      pair();

      Effects:
        Initializes  its  members  as  if implemented: pair() : first(T1()),
        second(T2()) {}

      pair(const T1& x, const T2& y);

      Effects:
        The constructor initializes first with x and second with y.

      template<class U, class V> pair(const pair<U, V> &p);

      Effects:
        Initializes members from the corresponding members of the  argument,
        performing implicit conversions as needed.

      template <class T1, class T2>
        bool operator==(const pair<T1, T2>& x, const pair<T1, T2>& y);

      Returns:
        x.first == y.first && x.second == y.second.

      template <class T1, class T2>
        bool operator<(const pair<T1, T2>& x, const pair<T1, T2>& y);

      Returns:
        x.first  < y.first || (!(y.first < x.first) && x.second < y.second).

      template <class T1, class T2>
        pair<T1, T2> make_pair(const T1& x, const T2& y);

      Returns:
        pair<T1, T2>(x, y).

    2 [Example: In place of:
        return pair<int, double>(5, 3.1415926); // explicit types
      a C++ program may contain:
        return make_pair(5, 3.1415926); // types are deduced
       --end example]

      20.3  Function objects                          [lib.function.objects]

    1 Function objects are objects with an  operator()  defined.   They  are
      important  for  the effective use of the library.  In the places where
      one would expect to pass a pointer to a  function  to  an  algorithmic
      template  (_lib.algorithms_),  the interface is specified to accept an
      object with an operator() defined.  This not  only  makes  algorithmic
      templates  work  with  pointers to functions, but also enables them to
      work with arbitrary function objects.

      Header <functional> synopsis

      namespace std {
      // clause _lib.base_, base:
        template <class Arg, class Result> struct unary_function;
        template <class Arg1, class Arg2, class Result> struct binary_function;
      // clause _lib.arithmetic.operations_, arithmetic operations:
        template <class T> struct plus;
        template <class T> struct minus;
        template <class T> struct multiplies;
        template <class T> struct divides;
        template <class T> struct modulus;
        template <class T> struct negate;

      // clause _lib.comparisons_, comparisons:
        template <class T> struct equal_to;
        template <class T> struct not_equal_to;
        template <class T> struct greater;
        template <class T> struct less;
        template <class T> struct greater_equal;
        template <class T> struct less_equal;
      // clause _lib.logical.operations_, logical operations:
        template <class T> struct logical_and;
        template <class T> struct logical_or;
        template <class T> struct logical_not;
      // clause _lib.negators_, negators:
        template <class Predicate> struct unary_negate;
        template <class Predicate>
          unary_negate<Predicate>  not1(const Predicate&);
        template <class Predicate> struct binary_negate;
        template <class Predicate>
          binary_negate<Predicate> not2(const Predicate&);
      // clause _lib.binders_, binders:
        template <class Operation>  class binder1st;
        template <class Operation, class T>
          binder1st<Operation> bind1st(const Operation&, const T&);
        template <class Operation> class binder2nd;
        template <class Operation, class T>
          binder2nd<Operation> bind2nd(const Operation&, const T&);
      // clause _lib.function.pointer.adaptors_, adaptors:
        template <class Arg, class Result> class pointer_to_unary_function;
        template <class Arg, class Result>
          pointer_to_unary_function<Arg,Result> ptr_fun(Result (*)(Arg));
        template <class Arg1, class Arg2, class Result>
          class pointer_to_binary_function;
        template <class Arg1, class Arg2, class Result>
          pointer_to_binary_function<Arg1,Arg2,Result> ptr_fun(Result (*)(Arg1,Arg2));
      // clause _lib.member.pointer.adaptors_, adaptors:
        template<class S, class T> class mem_fun_t;
        template<class S, class T, class A> class mem_fun1_t;
        template<class S, class T>
            mem_fun_t<S,T> mem_fun(S (T::*f)());
        template<class S, class T, class A>
            mem_fun1_t<S,T,A> mem_fun1(S (T::*f)(A));
        template<class S, class T> class mem_fun_ref_t;
        template<class S, class T, class A> class mem_fun1_ref_t;
        template<class S, class T>
            mem_fun_ref_t<S,T> mem_fun_ref(S (T::*f)());
        template<class S, class T, class A>
            mem_fun1_ref_t<S,T,A> mem_fun1_ref(S (T::*f)(A));
      }

    2 Using function objects together with function templates increases  the
      expressive  power  of the library as well as making the resulting code
      much more efficient.

    3 [Example: If a C++ program wants to have a by-element addition of  two
      vectors  a  and  b containing double and put the result into a, it can

      do:
        transform(a.begin(), a.end(), b.begin(), a.begin(), plus<double>());
       --end example]

    4 [Example: To negate every element of a:
        transform(a.begin(), a.end(), a.begin(), negate<double>());
      The corresponding functions will inline the addition and the negation.
       --end example]

    5 To enable adaptors and other components to manipulate function objects
      that take one or two arguments it is required  that  they  correspond-
      ingly  provide  typedefs  argument_type  and  result_type for function
      objects that take one argument and  first_argument_type,  second_argu-
      ment_type,  and  result_type  for function objects that take two argu-
      ments.

      20.3.1  Base                                                [lib.base]

    1 The following classes are provided to simplify  the  typedefs  of  the
      argument and result types:
        template <class Arg, class Result>
        struct unary_function {
          typedef Arg    argument_type;
          typedef Result result_type;
        };
        template <class Arg1, class Arg2, class Result>
        struct binary_function {
          typedef Arg1   first_argument_type;
          typedef Arg2   second_argument_type;
          typedef Result result_type;
        };

      20.3.2  Arithmetic operations              [lib.arithmetic.operations]

    1 The  library  provides  basic  function  object classes for all of the
      arithmetic operators in the language (_expr.mul_, _expr.add_).

      template <class T> struct plus : binary_function<T,T,T> {
        T operator()(const T& x, const T& y) const;
      };

    2 operator() returns x + y.

      template <class T> struct minus : binary_function<T,T,T> {
        T operator()(const T& x, const T& y) const;
      };

    3 operator() returns x - y.

      template <class T> struct multiplies : binary_function<T,T,T> {
        T operator()(const T& x, const T& y) const;
      };

    4 operator() returns x * y.

      template <class T> struct divides : binary_function<T,T,T> {
        T operator()(const T& x, const T& y) const;
      };

    5 operator() returns x / y.

      template <class T> struct modulus : binary_function<T,T,T> {
        T operator()(const T& x, const T& y) const;
      };

    6 operator() returns x % y.

      template <class T> struct negate : unary_function<T,T> {
        T operator()(const T& x) const;
      };

    7 operator() returns -x.

      20.3.3  Comparisons                                  [lib.comparisons]

    1 The library provides basic function object classes for all of the com-
      parison  operators  in  the  language (_expr.rel_, _expr.eq_).  In all
      cases, type T is convertible to type bool.

      template <class T> struct equal_to : binary_function<T,T,bool> {
        bool operator()(const T& x, const T& y) const;
      };

    2 operator() returns x == y.

      template <class T> struct not_equal_to : binary_function<T,T,bool> {
        bool operator()(const T& x, const T& y) const;
      };

    3 operator() returns x != y.

      template <class T> struct greater : binary_function<T,T,bool> {
        bool operator()(const T& x, const T& y) const;
      };

    4 operator() returns x > y.

      template <class T> struct less : binary_function<T,T,bool> {
        bool operator()(const T& x, const T& y) const;
      };

    5 operator() returns x < y.

      template <class T> struct greater_equal : binary_function<T,T,bool> {
        bool operator()(const T& x, const T& y) const;
      };

    6 operator() returns x >= y.

      template <class T> struct less_equal : binary_function<T,T,bool> {
        bool operator()(const T& x, const T& y) const;
      };

    7 operator() returns x <= y.

    8 For templates greater, less, greater_equal, and less_equal,  the  spe-
      cializations  for  any  pointer  type yield a total order, even if the
      built-in operators <, >, <=, >= do not.

      20.3.4  Logical operations                    [lib.logical.operations]

    1 The library provides basic function object classes for all of the log-
      ical   operators   in  the  language  (_expr.log.and_,  _expr.log.or_,
      _expr.unary.op_).

      template <class T> struct logical_and : binary_function<T,T,bool> {
        bool operator()(const T& x, const T& y) const;
      };

    2 operator() returns x && y.

      template <class T> struct logical_or : binary_function<T,T,bool> {
        bool operator()(const T& x, const T& y) const;
      };

    3 operator() returns x || y.

      template <class T> struct logical_not : unary_function<T,bool> {
        bool operator()(const T& x) const;
      };

    4 operator() returns !x.

      20.3.5  Negators                                        [lib.negators]

    1 Negators not1 and not2 take a unary and a  binary  predicate,  respec-
      tively, and return their complements (_expr.unary.op_).

      template <class Predicate>
        class unary_negate
          : public unary_function<Predicate::argument_type,bool> {
      public:
        explicit unary_negate(const Predicate& pred);
        bool operator()(const argument_type& x) const;
      };

    2 operator() returns !pred(x).

      template <class Predicate>
        unary_negate<Predicate> not1(const Predicate& pred);

      Returns:
        unary_negate<Predicate>(pred).

      template <class Predicate>
        class binary_negate
          : public binary_function<Predicate::first_argument_type,
                                   Predicate::second_argument_type, bool> {
        public:
          explicit binary_negate(const Predicate& pred);
          bool operator()(const first_argument_type&  x,
                          const second_argument_type& y) const;
        };

    3 operator() returns !pred(x,y).

      template <class Predicate>
        binary_negate<Predicate> not2(const Predicate& pred);

      Returns:
        binary_negate<Predicate>(pred).

      20.3.6  Binders                                          [lib.binders]

    1 Binders  bind1st and bind2nd take a function object f of two arguments
      and a value x and return a function object of one argument constructed
      out of f with the first or second argument correspondingly bound to x.

      20.3.6.1  Template class binder1st                    [lib.binder.1st]
        template <class Operation>
        class binder1st
          : public unary_function<Operation::second_argument_type,
                                  Operation::result_type> {
        protected:
          Operation                      op;
          Operation::first_argument_type value;
        public:
          binder1st(const Operation& x, const Operation::first_argument_type& y);
          result_type operator()(const argument_type& x) const;
        };

    1 The constructor initializes op with x and value with y.

    2 operator() returns op(value,x).

      20.3.6.2  bind1st                                       [lib.bind.1st]

      template <class Operation, class T>
        binder1st<Operation> bind1st(const Operation& op, const T& x);

      Returns:
        binder1st<Operation>(op, Operation::first_argument_type(x)).

      20.3.6.3  Template class binder2nd                    [lib.binder.2nd]
        template <class Operation>
        class binder2nd
          : public unary_function<Operation::first_argument_type,
                                  Operation::result_type> {
        protected:
          Operation                       op;
          Operation::second_argument_type value;
        public:
          binder2nd(const Operation& x, const Operation::second_argument_type& y);
          result_type operator()(const argument_type& x) const;
        };

    1 The constructor initializes op with x and value with y.

    2 operator() returns op(x,value).

      20.3.6.4  bind2nd                                       [lib.bind.2nd]

      template <class Operation, class T>
        binder2nd<Operation> bind2nd(const Operation& op, const T& x);

      Returns:
        binder2nd<Operation>(op, Operation::second_argument_type(x)).

    1 [Example:
        find_if(v.begin(), v.end(), bind2nd(greater<int>(), 5));
      finds the first integer in vector v greater than 5;
        find_if(v.begin(), v.end(), bind1st(greater<int>(), 5));
      finds the first integer in v less than 5.   --end example]

      20.3.7  Adaptors for pointers to       [lib.function.pointer.adaptors]
           functions

    1 To  allow  pointers to (unary and binary) functions to work with func-
      tion adaptors the library provides:
        template <class Arg, class Result>
        class pointer_to_unary_function : public unary_function<Arg, Result> {
        public:
          explicit pointer_to_unary_function(Result (*f)(Arg));
          Result operator()(Arg x) const;
        };

    2 operator() returns f(x).

      template <class Arg, class Result>
        pointer_to_unary_function<Arg, Result> ptr_fun(Result (*f)(Arg));

      Returns:
        pointer_to_unary_function<Arg, Result>(f).
            template <class Arg1, class Arg2, class Result>
            class pointer_to_binary_function : public binary_function<Arg1,Arg2,Result> {
            public:
              explicit pointer_to_binary_function(Result (*f)(Arg1, Arg2));
              Result operator()(Arg1 x, Arg2 y) const;
            };

    3 operator() returns f(x,y).

      template <class Arg1, class Arg2, class Result>
        pointer_to_binary_function<Arg1,Arg2,Result>
          ptr_fun(Result (*f)(Arg1, Arg2));

      Returns:
        pointer_to_binary_function<Arg1,Arg2,Result>(f).

    4 [Example:
          replace_if(v.begin(), v.end(), not1(bind2nd(ptr_fun(strcmp), "C")), "C++");
      replaces each C with C++ in sequence v.2)  --end example]

      20.3.8  Adaptors for pointers to         [lib.member.pointer.adaptors]
           members

    1 The purpose of the following is to provide  the  same  facilities  for
      pointer  to  members  as  those  provided for pointers to functions in
      _lib.function.pointer.adaptors_.
        template <class S, class T> class mem_fun_t
              : public unary_function<T*, S> {
        public:
          explicit mem_fun_t(S (T::*p)());
          S operator()(T* p);
      };

    2 mem_fun_t calls the member function it is  initialized  with  given  a
      pointer argument.
        template <class S, class T, class A> class mem_fun1_t
              : public binary_function<T*, A, S> {
        public:
          explicit mem_fun1_t(S (T::*p)(A));
          S operator()(T* p, A x);
      };

    3 mem_fun1_t  calls  the  member function it is initialized with given a
      pointer argument and an additional argument of the appropriate type.
        template<class S, class T> mem_fun_t<S,T>
           mem_fun(S (T::*f)());
        template<class S, class T, class A> mem_fun1_t<S,T,A>
           mem_fun1(S (T::*f)(A));

    4 mem_fun(&X::f) returns an object through  which  X::f  can  be  called
      given  a  pointer  to an X followed by the argument required for f (if
      any).
        template <class S, class T> class mem_fun_ref_t
              : public unary_function<T, S> {
        public:
          explicit mem_fun_ref_t(S (T::*p)());
          S operator()(T& p);
      };

    5 mem_fun_ref_t calls the member function it is initialized with given a
      reference argument.

      _________________________
      2) Implementations that have multiple pointer to function  types  pro-
      vide additional ptr_fun template functions.

        template <class S, class T, class A> class mem_fun1_ref_t
              : public binary_function<T, A, S> {
        public:
          explicit mem_fun1_ref_t(S (T::*p)(A));
          S operator()(T& p, A x);
      };

    6 mem_fun1_ref_t  calls the member function it is initialized with given
      a reference argument and an additional  argument  of  the  appropriate
      type.
        template<class S, class T> mem_fun_ref_t<S,T>
           mem_fun_ref(S (T::*f)());
        template<class S, class T, class A> mem_fun1_ref_t<S,T,A>
           mem_fun1_ref(S (T::*f)(A));

    7 mem_fun_ref(&X::f)  returns an object through which X::f can be called
      given a reference to an X followed by the argument required for f  (if
      any).

      20.4  Memory                                              [lib.memory]

      Header <memory> synopsis

      namespace std {
      // clause _lib.default.allocator_, the default allocator:
        template <class T> class allocator;
        template <> class allocator<void>;
        template <class T, class U>
          bool operator==(const allocator<T>&, const allocator<U>&) throw();
        template <class T, class U>
          bool operator!=(const allocator<T>&, const allocator<U>&) throw();
      // clause _lib.storage.iterator_, raw storage iterator:
        template <class OutputIterator, class T> class raw_storage_iterator;
      // clause _lib.temporary.buffer_, temporary buffers:
        template <class T>
          pair<T*,ptrdiff_t> get_temporary_buffer(ptrdiff_t n);
        template <class T>
          void return_temporary_buffer(T* p);
      // clause _lib.specialized.algorithms_, specialized algorithms:
        template <class InputIterator, class ForwardIterator>
          ForwardIterator
            uninitialized_copy(InputIterator first, InputIterator last,
                               ForwardIterator result);
        template <class ForwardIterator, class T>
          void uninitialized_fill(ForwardIterator first, ForwardIterator last,
                                  const T& x);
        template <class ForwardIterator, class Size, class T>
          void uninitialized_fill_n(ForwardIterator first, Size n, const T& x);
      // clause _lib.auto.ptr_, pointers:
        template<class X> class auto_ptr;
      }

      20.4.1  The default allocator                  [lib.default.allocator]
      namespace std {
        template <class T> class allocator;
        // specialize for void:
        template <> class allocator<void> {
        public:
          typedef void*       pointer;
          typedef const void* const_pointer;
          //  reference-to-void members are impossible.
          typedef void  value_type;
          template <class U> struct rebind { typedef allocator<U> other; };
        };
        template <class T> class allocator {
         public:
          typedef size_t    size_type;
          typedef ptrdiff_t difference_type;
          typedef T*        pointer;
          typedef const T*  const_pointer;
          typedef T&        reference;
          typedef const T&  const_reference;
          typedef T         value_type;
          template <class U> struct rebind { typedef allocator<U> other; };
          allocator() throw();
          allocator(const allocator&) throw();
          template <class U> allocator(const allocator<U>&) throw();
         ~allocator() throw();
          pointer address(reference x) const;
          const_pointer address(const_reference x) const;
          pointer allocate(
            size_type, typename allocator<void>::const_pointer hint = 0);
          void deallocate(pointer p, size_type n);
          size_type max_size() const throw();
          void construct(pointer p, const T& val);
          void destroy(pointer p);
        };
      }

      20.4.1.1  allocator members                    [lib.allocator.members]

      pointer address(reference x) const;

      Returns:
        &x.

      const_pointer address(const_reference x) const;

      Returns:
        &x.

      pointer allocate(size_type n, allocator<void>::const_pointer hint=0);

      Notes:
        Uses ::operator new(size_t) (_lib.new.delete_).
      Requires:
        hint  either  0  or previously obtained from member allocate and not
        yet passed to member deallocate.  The value hint may be used  by  an
        implementation to help improve performance3).
      Returns:
        a pointer to the initial element of an array of storage of size n  *
        sizeof(T), aligned appropriately for objects of type T.
      Note:
        the storage is obtained by calling ::operator new(size_t), but it is
        unspecified when or how often this function is called.  The  use  of
        hint is unspecified, but intended as an aid to locality if an imple-
        mentation so desires.
      Throws:
        bad_alloc if the storage cannot be obtained.

      void deallocate(pointer p, size_type n);

      Requires:
        p shall be a pointer value obtained from allocate().  n shall  equal
        the value passed as the first argument to the invocation of allocate
        which returned p.
      Effects:
        Deallocates the storage referenced by p.
      Notes:
        Uses ::operator delete(void*) (_lib.new.delete_), but it is unspeci-
        fied when this function is called.

      size_type max_size() const throw();

      Returns:
        the  largest value N for which the call allocate(N,0) might succeed.

      void construct(pointer p, const_reference val);

      Returns:
        new((void *)p) T(val)

      void destroy(pointer p);

      Returns:
        ((T*)p)->~T()

      _________________________
      3)  In a container member function, the address of an adjacent element
      is often a good choice to pass for this argument.

      20.4.1.2  allocator globals                    [lib.allocator.globals]

      template <class T1, class T2>
        bool operator==(const allocator<T1>&, const allocator<T2>&) throw();

      Returns:
        true.

      template <class T1, class T2>
        bool operator!=(const allocator<T1>&, const allocator<T2>&) throw();

      Returns:
        false.

      20.4.2  Raw storage iterator                    [lib.storage.iterator]

    1 raw_storage_iterator is provided to enable  algorithms  to  store  the
      results into uninitialized memory.  The formal template parameter Out-
      putIterator is required to have its operator*  return  an  object  for
      which  operator&  is  defined  and returns a pointer to T, and is also
      required to satisfy the requirements of an output iterator  (_lib.out-
      put.iterators_).
      namespace std {
        template <class OutputIterator, class T>
        class raw_storage_iterator
          : public iterator<output_iterator_tag,void,void> {
        public:
          explicit raw_storage_iterator(OutputIterator x);
          raw_storage_iterator<OutputIterator,T>& operator*();
          raw_storage_iterator<OutputIterator,T>& operator=(const T& element);
          raw_storage_iterator<OutputIterator,T>& operator++();
          raw_storage_iterator<OutputIterator,T>  operator++(int);
        };
      }

      raw_storage_iterator(OutputIterator x);

      Effects:
        Initializes  the  iterator  to  point  to  the same value to which x
        points.

      raw_storage_iterator<OutputIterator,T>& operator*();

      Returns:
        *this

      raw_storage_iterator<OutputIterator,T>& operator=(const T& element);

      Effects:
        Constructs a value from element at the location to which the  itera-
        tor points.
      Returns:
        A reference to the iterator.

      raw_storage_iterator<OutputIterator,T>& operator++();

      Effects:
        Pre-increment:  advances the iterator and returns a reference to the
        updated iterator.

      raw_storage_iterator<OutputIterator,T> operator++(int);

      Effects:
        Post-increment:  advances the iterator and returns the old value  of
        the iterator.

      20.4.3  Temporary buffers                       [lib.temporary.buffer]

      template <class T>
        pair<T*, ptrdiff_t> get_temporary_buffer(ptrdiff_t n);

      Effects:
        Obtains  a pointer to storage sufficient to store up to n adjacent T
        objects.
      Returns:
        A pair containing the buffer's address and capacity (in the units of
        sizeof(T)), or a pair of 0 values if no storage can be obtained.

      template <class T> void return_temporary_buffer(T* p);

      Effects:
        Deallocates the buffer to which p points.
      Requires:
        The  buffer  shall  have  been  previously  allocated  by get_tempo-
        rary_buffer.

      20.4.4  Specialized algorithms            [lib.specialized.algorithms]

    1 All the iterators that are used as formal template parameters  in  the
      following  algorithms  are required to  have their operator* return an
      object for which operator& is defined and returns a pointer to T.   In
      the   algorithm  uninitialized_copy,  the  formal  template  parameter
      InputIterator is required to satisfy  the  requirements  of  an  input
      iterator (_lib.input.iterators_).  In all of the following algorithms,
      the formal template parameter ForwardIterator is required  to  satisfy
      the  requirements  of a forward iterator (_lib.forward.iterators_) and
      also   to   satisfy   the   requirements   of   a   mutable   iterator

      (_lib.iterator.requirements_).

      20.4.4.1  uninitialized_copy                  [lib.uninitialized.copy]

      template <class InputIterator, class ForwardIterator>
        ForwardIterator
          uninitialized_copy(InputIterator first, InputIterator last,
                             ForwardIterator result);

      Effects:

      while (first != last)
              new (static_cast<void*>(&*result++))
                      typename iterator_traits<ForwardIterator>::value_type(*first++);

      Returns:
        result

      20.4.4.2  uninitialized_fill                  [lib.uninitialized.fill]

      template <class ForwardIterator, class T>
        void uninitialized_fill(ForwardIterator first, ForwardIterator last,
                                const T& x);

      Effects:

      while (first != last)
              new (static_cast<void*>(&*first++))
                      typename iterator_traits<ForwardIterator>::value_type(x);

      20.4.4.3  uninitialized_fill_n              [lib.uninitialized.fill.n]

      template <class ForwardIterator, class Size, class T>
        void uninitialized_fill_n(ForwardIterator first, Size n, const T& x);

      Effects:

      while (n--)
              new (static_cast<void*>(&*result++))
                      typename iterator_traits<ForwardIterator>::value_type(*first++);

      20.4.5  Template class auto_ptr                         [lib.auto.ptr]

    1 Template  auto_ptr  stores a pointer to an object obtained via new and
      deletes that object when it itself is destroyed (such as when  leaving
      block scope _stmt.dcl_).
      namespace std {
        template<class X> class auto_ptr {
        public:
          typedef X element_type;
        // _lib.auto.ptr.cons_ construct/copy/destroy:
          explicit auto_ptr(X* p =0) throw();
          auto_ptr(const auto_ptr&) throw();
          template<class Y> auto_ptr(const auto_ptr<Y>&) throw();
          auto_ptr& operator=(const auto_ptr&) throw();
          template<class Y> auto_ptr& operator=(const auto_ptr<Y>&) throw();
         ~auto_ptr();
        // _lib.auto.ptr.members_ members:
          X& operator*() const throw();
          X* operator->() const throw();
          X* get() const throw();
          X* release() const throw();
        };
      }

    2 The  auto_ptr provides a semantics of strict ownership.  After initial
      construction an auto_ptr owns the object it holds a pointer to.  Copy-
      ing an auto_ptr copies the pointer and transfers ownership to the des-
      tination.  If more than one auto_ptr owns the same object at the  same
      time the behaviour of the program is undefined.

      20.4.5.1  auto_ptr constructors                    [lib.auto.ptr.cons]

      explicit auto_ptr(X* p =0) throw();

      Postconditions:
        *this holds the pointer to p.  *this owns *get() if and only if p is
        not a null pointer.

      auto_ptr(const auto_ptr& a) throw();

      Effects:
        Calls a.release().
      Postconditions:
        *this holds the  pointer  returned  from  a.release().   *this  owns
        *get() if and only if a owns *a.

      template<class Y> auto_ptr(const auto_ptr<Y>& a) throw();

      Requires:
        Y* can be implicitly converted to X*.

      Effects:
        Calls a.release().
      Postconditions:
        *this  holds  the  pointer  returned  from  a.release().  *this owns
        *get() if and only if a owns *a.

      auto_ptr& operator=(const auto_ptr& a) throw();

      Requires:
        The expression delete get() is well formed.
      Effects:
        If *this is the same object as a there are no  effects.   Otherwise,
        call a.release(), and if *this owns *get() then delete get().
      Returns:
        *this.
      Postconditions:
        If  *this  is  not the same object as a then *this holds the pointer
        returned from a.release().  *this owns *get() if and only if a owned
        *a on entry.

      template<class Y> auto_ptr& operator=(const auto_ptr<Y>& a) throw();

      Requires:
        Y*  can  be implicitly converted to X*.  The expression delete get()
        is well formed.
      Effects:
        If *this is the same object as a there are no  effects.   Otherwise,
        call a.release(), and if *this owns *get() then delete get().
      Returns:
        *this.
      Postconditions:
        If  *this  is  not the same object as a then *this holds the pointer
        returned from a.release().  *this owns *get() if and only if a owned
        *a on entry.

      ~auto_ptr();

      Requires:
        The expression delete get() is well formed.
      Effects:
        If *this owns *get() then delete get().

      20.4.5.2  auto_ptr members                      [lib.auto.ptr.members]

      X& operator*() const throw();

      Requires:
        get() != 0

      Returns:
        *get()

      X* operator->() const throw();

      Returns:
        get()

      X* get() const throw();

      Returns:
        The pointer *this holds.

      X* release() const throw();

      Returns:
        get()
      Postcondition:
        *this is not the owner of *get().

      20.4.6  C Library                                       [lib.c.malloc]

    1 Header <cstdlib> (Table 7):

                        Table 7--Header <cstdlib> synopsis

                         +------------------------------+
                         |   Type          Name(s)      |
                         +------------------------------+
                         |Functions:   calloc   malloc  |
                         |             free     realloc |
                         +------------------------------+

    2 The contents are the same as the Standard C library header <stdlib.h>,
      with the following changes:

    3 The functions calloc(), malloc(), and  realloc()  do  not  attempt  to
      allocate  storage by calling ::operator new() (_lib.support.dynamic_).

    4 The function free() does not attempt to deallocate storage by  calling
      ::operator delete().

      SEE ALSO: ISO C clause 7.11.2.

    5 Header <cstring> (Table 8):

                        Table 8--Header <cstring> synopsis

                         +------------------------------+
                         |   Type          Name(s)      |
                         +------------------------------+
                         |Macro:       NULL             |
                         +------------------------------+
                         |Type:        size_t           |
                         +------------------------------+
                         |Functions:   memchr    memcmp |
                         |memcpy       memmove   memset |
                         +------------------------------+

    6 The contents are the same as the Standard C library header <string.h>,
      with the change to memchr() specified in clause _lib.c.strings_.

      SEE ALSO: ISO C clause 7.11.2.

      20.5  Date and time                                    [lib.date.time]

    1 Header <ctime> (Table 9):

                         Table 9--Header <ctime> synopsis

               +---------------------------------------------------+
               | Type                     Name(s)                  |
               +---------------------------------------------------+
               |Macros:   NULL                                     |
               +---------------------------------------------------+
               |Types:    size_t   clock_t    time_t               |
               +---------------------------------------------------+
               |Struct:   tm                                       |
               +---------------------------------------------------+
               |Functions:                                         |
               |asctime   clock    difftime   localtime   strftime |
               |ctime     gmtime   mktime     time                 |
               +---------------------------------------------------+

    2 The contents are the same as the Standard C library header <time.h>.

      SEE ALSO: ISO C clause 7.12, Amendment 1 clause 4.6.4.