isnormal

fpclassify(3)		  Linux Programmer’s Manual		fpclassify(3)



NAME
       fpclassify,  isfinite, isnormal, isnan - floating-point classification
       macros

SYNOPSIS
       #include <math.h>

       int fpclassify(x);

       int isfinite(x);

       int isnormal(x);

       int isnan(x);

       int isinf(x);

DESCRIPTION
       Floating point numbers can have special values, such  as	 infinite  or
       NaN. With the macro fpclassify(x) you can find out what type x is. The
       macro takes any floating-point expression  as  argument.	  The  result
       takes one of the following values:

       FP_NAN x is "Not a Number".

       FP_INFINITE
	      x is either plus or minus infinity.

       FP_ZERO
	      x is zero.

       FP_SUBNORMAL
	      x is too small to be represented in normalized format.

       FP_NORMAL
	      if  nothing  of  the  above is correct that it must be a normal
	      floating-point number.

       The other macros provide a short answer to some standard questions.

       isfinite(x)
	      (fpclassify(x) != FP_NAN && fpclassify(x) != FP_INFINITE)

       isnormal(x)
	      (fpclassify(x) == FP_NORMAL)

       isnan(x)
	      (fpclassify(x) == FP_NAN)

       isinf(x)
	      (fpclassify(x) == FP_INFINITE)

NOTE
CONFORMING TO
       C99

SEE ALSO
       isgreater(3), isinf(3)



				  2002-07-27			fpclassify(3)