trusty (3) isunordered.3posix.gz

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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 argument 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>


       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition,
       Standard  for  Information Technology -- 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 .