ISGREATER(3)		   Linux Programmers Manual		 ISGREATER(3)



NAME
       isgreater,    isgreaterequal,   isless,	 islessequal,	islessgreater,
       isunordered - macros to test a relation

SYNOPSIS
       #include 

       int isgreater(x,y);

       int isgreaterequal(x,y);

       int isless(x,y);

       int islessequal(x,y);

       int islessgreater(x,y);

       int isunordered(x,y);

       Compile with -std=c99; link with -lm.

DESCRIPTION
       The normal relation operations (like less) will	fail  if  one  of  the
       operands  is  NaN.   This  will cause an exception.  To avoid this, C99
       defines these macros.  The macros  are  guaranteed  to  evaluate  their
       operands  only  once.   The  operand  can be of any real floating-point
       type.

       isgreater()
	      determines (x) > (y) without an exception if x or y is NaN.

       isgreaterequal()
	      determines (x) >= (y) without an exception if x or y is NaN.

       isless()
	      determines (x) < (y) without an exception if x or y is NaN.

       islessequal()
	      determines (x) <= (y) without an exception if x or y is NaN.

       islessgreater()
	      determines (x) < (y) || (x) > (y) without an exception if x or y
	      is  NaN.	 This  macro  is not equivalent to x != y because that
	      expression is true if x or y is NaN.

       isunordered()
	      is true if x or y is NaN and false otherwise.

CONFORMING TO
       C99.

NOTES
       Not all hardware supports these functions, and where it	doesnt,  they
       will  be emulated by macros.  This will give you a performance penalty.
       Dont use these functions if NaN is of no concern for you.

SEE ALSO
       fpclassify(3), isnan(3)

COLOPHON
       This page is part of release 3.05 of the Linux  man-pages  project.   A
       description  of	the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.



				  2002-07-27			  ISGREATER(3)