ieee_is_nan(3I)

NAME
     IEEE_IS_NAN, ISNAN - Tests for x being a NaN

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

IMPLEMENTATION
     UNICOS/mk, IRIX systems, CRAY T90 systems that support IEEE
     floating-point arithmetic

     CF90, MIPSpro 7 Fortran 90, MIPSpro Fortran 77

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 CF90 and MIPSpro 7 Fortran 90.  ISNAN
     is accepted by the CF90, MIPSpro 7 Fortran 90, and MIPSpro Fortran 77
     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

SEE ALSO
     Intrinsic Procedures Reference Manual for the printed version of this
     man page.