isnan(3p)
NAME
isnan - test for a NaN
SYNOPSIS
#include <math.h> int isnan(real-floating x);
DESCRIPTION
The isnan() macro shall determine whether its argument value is a NaN.
First, an argument represented in a format wider than its semantic type
is converted to its semantic type. Then determination is based on the
type of the argument.
RETURN VALUE
The isnan() macro shall return a non-zero value if and only if its
argument has a NaN value.
ERRORS
No errors are defined.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
fpclassify() , isfinite() , isinf() , isnormal() , signbit() , 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 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 .