ISNAN(3C-SVR4)      RISC/os Reference Manual       ISNAN(3C-SVR4)



NAME
     isnan, isnand, isnanf, finite, fpclass, unordered - deter-
          mine type of floating-point number

SYNOPSIS
     #include <ieeefp.h>

     int isnand (double dsrc);

     int isnanf (float fsrc);

     int finite (double dsrc);

     fpclasst fpclass (double dsrc);

     int unordered (double dsrc1, double dsrc2);

     #include <math.h>

     int isnan (double dsrc);

DESCRIPTION
     isnan, isnand, and isnanf return true (1) if the argument
     dsrc or fsrc is a NaN; otherwise they return false (0).  The
     functionality of isnan is identical to that of isnand.

     isnanf is implemented as a macro included in the ieeefp.h
     header file.

     fpclass returns the class the dsrc belongs to.  The 10 pos-
     sible classes are as follows:

          FP_SNAN      signaling NaN
          FP_QNAN      quiet NaN
          FP_NINF      negative infinity
          FP_PINF      positive infinity
          FP_NDENORM   negative denormalized non-zero
          FP_PDENORM   positive denormalized non-zero
          FP_NZERO     negative zero
          FP_PZERO     positive zero
          FP_NNORM     negative normalized non-zero
          FP_PNORM     positive normalized non-zero

     finite returns true (1) if the argument dsrc is neither
     infinity nor NaN; otherwise it returns false (0).

     unordered returns true (1) if one of its two arguments is
     unordered with respect to the other argument.  This is
     equivalent to reporting whether either argument is NaN.  If
     neither of the arguments is NaN, false (0) is returned.





                        Printed 11/19/92                   Page 1

ISNAN(3C-SVR4)      RISC/os Reference Manual       ISNAN(3C-SVR4)



     None of these routines generate any exception, even for sig-
     naling NaNs.

SEE ALSO
     fpgetround(3C), intro(3M).


















































 Page 2                 Printed 11/19/92