DCX$_INVCTX        Error. The context variable is invalid, or the
                       context area is invalid or corrupted. This may
                       be caused by a failure to call the appropriate
                       routine to initialize the context variable or
                       by an application program error.
    DCX$_INVDATA       Error. A compressed data record is invalid
                       (probably truncated) and therefore cannot be
                       expanded.
    DCX$_INVMAP        Error; invalid map. The map argument was not
                       specified correctly, or the context area is
                       invalid.
    DCX$_NORMAL        Normal successful completion.
    DCX$_TRUNC         Warning. The expanded data record has been
                       truncated because the out_rec descriptor did
                       not specify enough memory to accommodate the
                       record.

    This routine also returns any condition values returned by
    LIB$ANALYZE_SDESC_R2 and LIB$SCOPY_R_DX.