ieee_is_nan(3I)

NAME
     IEEE_IS_NAN - Tests for x being a NaN

SYNOPSIS
     IEEE_IS_NAN ([X=]x)

IMPLEMENTATION
     UNICOS/mk and IRIX systems

     CRAY T90 systems that support IEEE floating-point arithmetic

STANDARDS
     CF90 and MIPSpro 7 Fortran 90 compiler extension to Fortran 90

     IEEE Standard for Binary Floating-point Arithmetic

DESCRIPTION
     The IEEE_IS_NAN intrinsic function returns the value TRUE if x is a
     NaN and return the value FALSE otherwise.

     This function accepts the following argument:

     x         Must be of type real.

     IEEE_IS_NAN is an elemental 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 one of the following statements in
     your program:

     * On UNICOS and UNICOS/mk systems:  USE CRI_IEEE_DEFINITIONS

     * On UNICOS, UNICOS/mk, and IRIX systems:  USE FTN_IEEE_DEFINITIONS

     The CRI_IEEE_DEFINITIONS module is obsolescent.  It will be removed
     for the CF90 4.0 release.

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, publication SR-2138, for the
     printed version of this man page.