VMS Help CC, Messages, BITCONSTSIGN  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 Message        <Context> the integer constant "<constant>" does not
                have the same sign as the 1-bit bitfield it is being
                converted to.

 Description    Either an unsigned 1-bit bitfield was assigned -1, or
                a signed 1-bit bitfield was assigned 1.  This may not
                be what you intended.

 User Action    Change the constant to be the appropriate sign.