ieee_support_nan

Date:

10-12-2011

NAME

IEEE_SUPPORT_NAN - Determine if the system supports IEEE Not-a-Number (NaN) for real variables

SYNOPSIS

IEEE_SUPPORT_NAN ([[X=]x])

STANDARDS

Fortran

IEEE Standard for Binary Floating-point Arithmetic

DESCRIPTION

The function IEEE_SUPPORT_NAN() can be used to determine if a system supports the IEEE NaNs for a particular kind of real or for all reals.

This function accepts the following argument:

x

Must be of type real. It may be a scalar or an array.

IEEE_SUPPORT_NAN() is an inquiry function. The name of this intrinsic cannot be passed as an argument.

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 is default logical.

If x is present, the result is true if the system supports IEEE NaNs for real variables of the same kind type as x; otherwise, the result is false.

If x is not present, the result is true if the system supports IEEE NaNs for all real variables supported on this system; otherwise, the result is false.

EXAMPLES

Example 1:

USE, INTRINSIC :: IEEE_ARITHMETIC
REAL xdef
REAL(8) x8
LOGICAL x_nan_supported, allx_nan_supported

x_nan_supported = IEEE_SUPPORT_NAN(xdef)

allx_nan_supported = IEEE_SUPPORT_NAN()