ieee_is_nan(3I)

NAME
     IEEE_IS_NAN, ISNAN - Tests for x being a NaN

SYNOPSIS
     IEEE_IS_NAN ([X=]x)
     ISNAN ([X=]x)

STANDARDS
     Fortran extensions

     IEEE Standard for Binary Floating-point Arithmetic

     Extension to the IEEE Standard for Binary Floating-point Arithmetic:
     ISNAN

DESCRIPTION
     The IEEE_IS_NAN and ISNAN intrinsic functions return the value TRUE if
     x is a NaN and return the value FALSE otherwise.  IEEE_IS_NAN and
     ISNAN are synonyms.  These functions accept the following argument:

     x         Must be of type real.

     These are elemental intrinsic functions.  The names of these
     intrinsics cannot be passed as arguments.

     IEEE_IS_NAN is accepted by the MIPSpro Fortran 90 compiler.  ISNAN is
     accepted by the Fortran 77 and Fortran 90 compilers.

RETURN VALUES
     The result type and type parameter are of type default logical.  If x
     is an array, the result is an array of the same shape as x.

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

EXAMPLES
          REAL   x
          ...                       ! Compute X.
          IF (IEEE_IS_NAN(x)) THEN
             ...                    ! Do something.
          ELSE
             ...                    ! Do something else.
          END IF