Standard C++	Library
 		 Copyright 1996, Rogue Wave Software, Inc.

 NAME

   numeric_limits  - A class for	representing information about scalar
   types.

 SPECIALIZATIONS

   numeric_limits<float>
   numeric_limits<double>
   numeric_limits<long double>
   numeric_limits<short>
   numeric_limits<unsigned short>
   numeric_limits<int>
   numeric_limits<unsigned int>
   numeric_limits<long>
   numeric_limits<unsigned long>
   numeric_limits<char>
   numeric_limits<wchar_t>
   numeric_limits<unsigned char>
   numeric_limits<signed	char>
   numeric_limits<bool>

 SYNOPSIS

   #include <limits>

   template <class T>
   class	numeric_limits ;

 DESCRIPTION

   numeric_limits is a class for	representing information about scalar
   types. Specializations are provided for each fundamental type, both
   floating point and integer, including bool.

   This class encapsulates information that is contained	in the
   <climits>  and <cfloat> headers, as well as providing additional
   information  that is not contained in any existing C or C++ header.

   Not all of the information provided by members is meaningful for all
   specializations of numeric_limits.  Any value which is not
   meaningful  for a particular type is set to 0 or false.

 INTERFACE

   template <class T>
   class	numeric_limits {

   public:

    // General -- meaningful for	all specializations.

      static const bool is_specialized ;
      static T min ();
      static T max ();
      static const int radix ;
      static const int digits ;
      static const int digits10 ;
      static const bool is_signed ;
      static const bool is_integer ;
      static const bool is_exact	;
      static const bool traps ;
      static const bool is_modulo ;
      static const bool is_bounded ;

    // Floating point specific.

      static T epsilon ();
      static T round_error ();
      static const int min_exponent10 ;
      static const int max_exponent10 ;
      static const int min_exponent ;

      static const int max_exponent ;
      static const bool has_infinity ;
      static const bool has_quiet_NaN ;
      static const bool has_signaling_NaN ;
      static const bool is_iec559 ;
      static const bool has_denorm ;
      static const bool tinyness_before ;
      static const float_round_style round_style	;
      static T denorm_min ();
      static T infinity ();
      static T quiet_NaN	();
      static T signaling_NaN ();
    };

   enum float_round_style {
     round_indeterminate	      =	-1,
     round_toward_zero	      =	 0,
     round_to_nearest	      =	 1,
     round_toward_infinity     =	 2,
     round_toward_neg_infinity =	 3
    };

 MEMBER FIELDS AND FUNCTIONS

   static T
   denorm_min ();
      Returns the minimum denormalized value. Meaningful	for all
      floating point types. For types that do not allow denormalized
      values, this method must return the minimum normalized value.

   static const int
   digits ;
      Number of radix digits which can be represented without change.
      For built-in integer types, digits will usually be the number of
      non-sign bits in the representation. For floating point types,
      digits is the number of radix digits in the mantissa.  This member
      is meaningful for all specializations that declare is_bounded to
      be true.

   static const int
   digits10 ;
      Number of base 10 digits that can be represented without change.
      Meaningful for all specializations that declare is_bounded to be
      true.

   static T
   epsilon ();
      Returns the machine epsilon (the difference between 1 and the least
      value greater than	1 that is representable).  This	function is
      meaningful for floating point types only.

   static const bool
   has_denorm ;
      This field	is true	if the type allows denormalized	values
      (variable number of exponent	bits).	It is meaningful for
      floating point types only.

   static const bool
   has_infinity ;
      This field	is true	if the type has	a representation for positive
      infinity.   It is meaningful for floating point types only.  This
      field must be true for any type claiming conformance to IEC 559.

   static const bool
   has_quiet_NaN	;
      This field	is true	is the type has	a representation for a quiet
      (non-signaling) "Not a Number".  It is meaningful for floating
      point types only and must be true for any type claiming
      conformance  to IEC 559.

   static const bool
   has_signaling_NaN ;
      This field	is true	if the type has	a representation for a
      signaling  "Not a Number". It is meaningful for floating point
      types only, and  must be true for any type claiming conformance
      to IEC 559.

   static T
   infinity ();
      Returns the representation	of positive infinity, if available.
      This member function is	meaningful for only those
      specializations that declare has_infinity to be	true.
      Required	for any	type claiming  conformance to IEC 559.

   static const bool
   is_bounded ;
      This field	is true	if the set of values representable by the type
      is finite.  All built-in C types are bounded;	this member
      would be false for arbitrary precision types.

   static const bool
   is_exact ;
      This static member	field is true if the type uses an exact
      representation.  All	integer	types are exact, but not vice
      versa. For example, rational and fixed-exponent representations
      are exact but not integer. This member is meaningful for all
      specializations.

   static const bool
   is_iec559 ;
      This member is true if and	only if	the type adheres to the	IEC
      559	standard.  It is meaningful for floating point types
      only. Must be  true for any type claiming conformance to IEC 559.

   static const bool
   is_integer ;
      This member is true if the	type is	integer.  This member is
      meaningful for all specializations.

   static const bool
   is_modulo ;
      This field	is true	if the type is modulo.	Generally, this	is
      false for floating types, true for unsigned integers, and true
      for signed integers on most machines. A type is modulo if it is
      possible to add two positive numbers, and have a result that wraps
      around to a third number, which is less.

   static const bool
   is_signed ;
      This member is true if the	type is	signed.	 This member is
      meaningful for all specializations.

   static const bool
   is_specialized ;
      Indicates whether numeric_limits has been specialized for type T.
      This flag must be true for all specializations of numeric_limits.
      In the default numeric_limits<T> template, this flag must be
      false.

   static T
   max ();
      Returns the maximum finite	value.	This function is meaningful
      for	all specializations that declare is_bounded to be
      true.

   static const int
   max_exponent ;
      Maximum positive integer such that	the radix raised to that power
      is in range.  This field is meaningful for floating point types
      only.

   static const int
   max_exponent10 ;
      Maximum positive integer such that	10 raised to that power	is in
      range. This field	is meaningful for floating point types only.

   static T
   min ();
      Returns the minimum finite	value.	For floating point types with
      denormalization, min()must return the minimum normalized value.
      The minimum denormalized value is provided by denorm_min().  This
      function is meaningful for	all specializations that declare
      is_bounded to be true.

   static const int
   min_exponent ;
      Minimum negative integer such that	the radix raised to that power
      is in range.  This field is meaningful for floating point types
      only.

   static const int
   min_exponent10 ;
      Minimum negative integer such that	10 raised to that power	is in
      range.  This field	is meaningful for floating point types only.

   static T
   quiet_NaN ();
      Returns the representation	of a quiet "Not	 a  Number", if
      available.  This function is meaningful only for those
      specializations that declare has_quiet_NaN to be true. This field
      is required for any type claiming conformance to IEC 559.

   static const int
   radix	;
      For floating types, specifies the base or radix of	the exponent
      representation (often 2). For integer types, this member must
      specify the base of the representation. This field	is meaningful
      for all specializations.

   static T
   round_error ();
      Returns the measure of the	maximum	rounding error.	This function
      is meaningful for floating point types only.

   static const float_round_style
   round_style ;
      The rounding style	for the	type.  Specializations for integer
      types must return round_toward_zero. This is meaningful for all
      floating point types.

   static T
   signaling_NaN();
      Returns the representation	of a signaling "Not a Number",	if
      available.  This function is meaningful for only those
      specializations that declare has_signaling_NaN to be true.  This
      function must be meaningful for any type claiming conformance to
      IEC 559.

   static const bool
   tinyness_before ;
      This member is true if tinyness is	detected before	rounding.  It
      is meaningful for floating point types only.

   static const bool
   traps	;
      This field	is true	if trapping is implemented for this type.
      The traps field is meaningful for all specializations.

 EXAMPLE

   //
   // limits.cpp
   //
    #include <limits>

   int main()
    {
       numeric_limits<float> float_info;
      if	(float_info.is_specialized && float_info.has_infinity)
       {
 	// get value of	infinity
        float finfinity=float_info.infinity();
       }
      return 0;
    }

 WARNING

   The specializations for wide chars and bool will only	be available
   if your compiler has implemented them	as real	types and not
   simulated	them with typedefs.

 SEE ALSO

   IEEE Standard	for Binary Floating-Point Arithmetic, 345 East 47th
   Street, New York, NY 10017

   Language Independent Arithmetic (LIA-1)

 STANDARDS CONFORMANCE
   ANSI X3J16/ISO WG21 Joint C++	Committee