isnan.3m (2010 09)

isnan(3M) isnan(3M)

NAME

isnan( ) - ﬂoating-point test for NaN

SYNOPSIS

#include <math.h>

int isnan(ﬂoating-type x);

DESCRIPTION

The isnan() macro determines whether its argument is a NaN. The argument must be of ﬂoating type.

For HP Integrity servers, the argument can be any ﬂoating type. For PA-RISC, the argument must be

either double or float.

The

isnan() macro implements the isnan() functionality recommended by the IEEE-754 standard

for ﬂoating-point arithmetic.

The

isnan() macro replaces the isnan() and

isnanf() functions, which are obsolete and are no

longer supported.

USAGE

To use the

isnan() macro, compile either with the default

-Ae option or with the -Aa and

-D_HPUX_SOURCE options. Make sure your program includes

<math.h>. Link in the math library by

specifying

-lm on the compiler or linker command line.

RETURN VALUE

The

isnan() macro returns a nonzero value if and only if its argument has a NaN value. The macro

raises no ﬂoating-point exceptions.

ERRORS

No errors are deﬁned.

EXAMPLES

Take certain actions if

x is not a NaN:

#include <math.h>

/*...*/

double x;

/*...*/

if (!isnan(x))

/*...*/

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isnan(3M) isnan(3M) NAME isnan( ) - floating-point test for NaN SYNOPSIS #include int isnan(floating-type x); DESCRIPTION The isnan() macro determines whether its argument is a NaN. The argument must be of floating type. For HP Integrity servers, the argument can be any floating type. For PA-RISC, the argument must be either double or float. The isnan() macro implements the isnan() functionality recommended by the IEEE-754 standard for floating-point arithmetic.
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(Notes) A (Notes) iA 2 Hewlett-Packard Company −1− HP-UX 11i Version 3: September 2010