Description

   These routines determine the class of IEEE floating-point values.
   They return one of the constants in the file <fp_class.h> and
   never cause an exception, even for signaling NaNs. These routines
   implement the recommended function class(x) in the appendix of
   the IEEE Std 754. The constants in <fp_class.h> refer to the
   following classes of values:

   Constant           Class

   FP_SNAN            Signaling NaN (Not-a-Number)
   FP_QNAN            Quiet NaN (Not-a-Number)
   FP_POS_INF         +Infinity
   FP_NEG_INF         -Infinity
   FP_POS_NORM        Positive normalized
   FP_NEG_NORM        Negative normalized
   FP_POS_DENORM      Positive denormalized
   FP_NEG_DENORM      Negative denormalized
   FP_POS_ZERO        +0.0 (positive zero)
   FP_NEG_ZERO        -0.0 (negative zero)


                          Entry-Point Names

   Generic
   Function   Data Type   OpenVMS                Tru64 UNIX
   Name       Required

   fp_class   S_FLOAT     math$fp_class_s        fp_classf
              T_FLOAT     math$fp_class_t        fp_class
              X_FLOAT     math$fp_class_x        fp_classl
              F_FLOAT     math$fp_class_f
              G_FLOAT     math$fp_class_g