ieee_is_nan

Date:: 10-12-2011

NAME

IEEE_IS_NAN - Tests for x being a NaN

SYNOPSIS

IEEE_IS_NAN ([X=]x)

STANDARDS

Fortran

IEEE Standard for Binary Floating-point Arithmetic

DESCRIPTION

The IEEE_IS_NAN intrinsic function returns the value TRUE if x is a NaN and otherwise, it returns the value FALSE. This function accepts the following argument:

x: Must be of type real.

IEEE_IS_NAN is an elemental intrinsic function. The name of this intrinsic cannot be passed as an argument.

IEEE_IS_NAN will not be invoked if IEEE_SUPPORT_NAN(X) has the value false.

NOTES

The IEEE intrinsic procedures use the named constants contained in a system module, so you must include the following statement in your program:

USE, INTRINSIC :: IEEE_ARITHMETIC

RETURN VALUES

The result type and type parameter are of type default logical.

The value returned has the value TRUE if x is a NaN and the value FALSE otherwise.

EXAMPLES

USE, INTRINSIC :: IEEE_ARITHMETIC
REAL   x
...
IF (IEEE_IS_NAN(x)) THEN
   ! Do something.
ELSE
   ! Do something else.
END IF