isnan(3C)       UNIX System V(C Programming Language Utilities)       isnan(3C)


NAME
      isnan, isnand, isnanf, isnanl, finite, finitel, fpclass, fpclassl,
      unordered, unorderedl - determine type of floating-point number

SYNOPSIS
      #include <ieeefp.h>

      int isnand (double dsrc);

      int isnanf (float fsrc);

      int isnanl (long double dsrc);

      int finite (double dsrc);

      int finitel (long double dsrc);

      fpclasst fpclass (double dsrc);

      fpclasst fpclassl (long double dsrc);

      int unordered (double dsrc1, double dsrc2);

      int unorderedl (long double dsrc1, long double dsrc2);

      #include <math.h>

      int isnan (double dsrc);

DESCRIPTION
      isnan, isnand, isnanf, and isnanl 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 and fpclassl return the class the dsrc belongs to.  The 10
      possible classes are as follows:
            FPSNAN      signaling NaN
            FPQNAN      quiet NaN
            FPNINF      negative infinity
            FPPINF      positive infinity
            FPNDENORM   negative denormalized non-zero
            FPPDENORM   positive denormalized non-zero
            FPNZERO     negative zero
            FPPZERO     positive zero
            FPNNORM     negative normalized non-zero
            FPPNORM     positive normalized non-zero

      finite and finitel return true (1) if the argument dsrc is neither
      infinity nor NaN; otherwise they return false (0).



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isnan(3C)       UNIX System V(C Programming Language Utilities)       isnan(3C)


      unordered and unorderedl return true (1) if one of the 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.

      None of these routines generate any exception, even for signaling NaNs.

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













































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