The Multiple-Precision Binary Subtraction routine performs
    subtraction on signed two's complement integers of arbitrary
    length.

    Format

      LIB$SUBX  minuend-array ,subtrahend-array ,difference-array

                [,array-length]

1  –  Returns

    OpenVMS usage:cond_value
    type:         longword (unsigned)
    access:       write only
    mechanism:    by value

2  –  Arguments

 minuend-array

    OpenVMS usage:vector_longword_signed
    type:         unspecified
    access:       read only
    mechanism:    by reference, array reference

    Minuend; a multiple-precision, signed two's complement integer.
    The minuend-array argument is the address of an array of signed
    longword integers that contains the minuend.

 subtrahend-array

    OpenVMS usage:vector_longword_signed
    type:         unspecified
    access:       read only
    mechanism:    by reference, array reference

    Subtrahend; a multiple-precision, signed two's complement
    integer. The subtrahend-array argument is the address of an array
    of signed longword integers that contains the subtrahend.

 difference-array

    OpenVMS usage:vector_longword_signed
    type:         unspecified
    access:       write only
    mechanism:    by reference, array reference

    Difference; a multiple-precision, signed two's complement integer
    result. The difference-array argument is the address of an array
    of signed longword integers that contains the difference.

 array-length

    OpenVMS usage:longword_signed
    type:         longword integer (signed)
    access:       read only
    mechanism:    by reference

    Length in longwords of the arrays to be operated on by LIB$SUBX.
    The array-length argument contains the address of a signed
    longword integer that is this length. The array-length argument
    must not be negative. The default length is 2 units.