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ISNAN 3M "Jul 12, 2006" "SunOS 5.11" "Mathematical Library Functions"
NAME
isnan - test for NaN
SYNOPSIS
cc [ flag... ] file... -lm [ library... ] #include <math.h> int isnan(double x);
c99 [ flag... ] file... -lm [ library... ] #include <math.h> int isnan(real\(emfloating x);
DESCRIPTION
In C90 mode, the isnan() function tests whether x is NaN.
In C99 mode, the isnan() macro determines whether its argument value is NaN. First, an argument represented in a format wider than its semantic type is converted to its semantic type. The determination is then based on the type of the argument.
RETURN VALUES
Both the isnan() function and macro return non-zero if and only if x is NaN.
ERRORS
No errors are defined.
WARNINGS
In C99 mode, the practice of explicitly supplying a prototype for isnan() after the line
#include <math.h>
is obsolete and will no longer work.
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
| ATTRIBUTE TYPE ATTRIBUTE VALUE |
| Interface Stability Standard |
| MT-Level MT-Safe |
SEE ALSO
math.h (3HEAD), fpclassify (3M), isfinite (3M), isinf (3M), isnormal (3M), signbit (3M), attributes (7), standards (7)