ISUNORDERED(3P) 					     POSIX Programmer's Manual						   ISUNORDERED(3P)

PROLOG

       This  manual page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (consult the correspond-
       ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

NAME

       isunordered - test if arguments are unordered

SYNOPSIS

       #include <math.h>

       int isunordered(real-floating x, real-floating y);

DESCRIPTION

       The isunordered() macro shall determine whether its arguments are unordered.

RETURN VALUE

       Upon successful completion, the isunordered() macro shall return 1 if its arguments are unordered, and 0 otherwise.

       If x or y is NaN, 0 shall be returned.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       The relational and equality operators support the usual mathematical relationships between numeric values. For any ordered pair of  numeric
       values,	exactly  one  of  the  relationships (less, greater, and equal) is true. Relational operators may raise the invalid floating-point
       exception when argument values are NaNs. For a NaN and a numeric value, or for two NaNs, just the  unordered  relationship  is  true.  This
       macro  is  a  quiet  (non-floating-point  exception  raising)  version of a relational operator. It facilitates writing efficient code that
       accounts for NaNs without suffering the invalid floating-point exception. In the SYNOPSIS section, real-floating indicates that	the  argu-
       ment shall be an expression of real-floating type.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       isgreater(), isgreaterequal(), isless(), islessequal(), islessgreater(), the Base Definitions volume of IEEE Std 1003.1-2001, <math.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
       Electrical  and	Electronics  Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE
       and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can  be  obtained
       online at http://www.opengroup.org/unix/online.html .

IEEE
/The Open Group						       2003							   ISUNORDERED(3P)