subroutine VarTableAdd(vid, class, cid)

        integer, intent(out):: vid
        integer, intent(in):: class, cid
        type(VAR_TABLE_ENTRY), allocatable:: tmp_table(:)
        integer:: n
    continue
        ! 必要ならば初期幅確保
        if (.not. allocated(table)) then
            allocate(table(table_ini_size))
            call entry_cleanup(table(:))
        endif
        ! 該当があれば参照数増加
        do, n = 1, size(table)
            if (table(n)%class == class .and. table(n)%cid == cid) then
                table(n)%refcount = table(n)%refcount + 1
                call DbgMessage('gt_vartable.add(class=%d cid=%d) found (ref=%d)',  i=(/table(n)%class, table(n)%cid, table(n)%refcount/))
                vid = n
                return
            endif
        enddo
        ! もし空きが無ければ表を拡張
        if (all(table(:)%class /= VTB_CLASS_UNUSED)) then
            n = size(table)
            allocate(tmp_table(n))
            tmp_table(:) = table(:)
            deallocate(table)
            allocate(table(n * 2))
            table(1:n) = tmp_table(1:n)
            table(n+1:n*2) = var_table_entry(VTB_CLASS_UNUSED, -1, 0)
        endif
        do, n = 1, size(table)
            if (table(n)%class == VTB_CLASS_UNUSED) then
                table(n)%class = class
                table(n)%cid = cid
                table(n)%refcount = 1
                vid = n
                return
            endif
        enddo
        vid = vid_invalid
    end subroutine

    subroutine VarTableDelete(vid, action, err)
        integer, intent(in):: vid
        logical, intent(out):: action
        logical, intent(out), optional:: err
        if (.not. allocated(table)) goto 999
        if (vid <= 0 .or. vid > size(table)) goto 999
        if (table(vid)%class <= VTB_CLASS_UNUSED) goto 999
        if (table(vid)%class > CLASSES_MAX) goto 999
        table(vid)%refcount = max(table(vid)%refcount - 1, 0)
        action = (table(vid)%refcount == 0)
        if (present(err)) err = .false.
        return
    999 continue
        action = .false.
        if (present(err)) err = .true.
    end subroutine

    subroutine VarTableLookup(vid, class, cid)
        integer, intent(in):: vid
        integer, intent(out), optional:: class, cid
        if (.not. allocated(table)) goto 999
        if (vid <= 0 .or. vid > size(table)) goto 999
        if (table(vid)%class <= VTB_CLASS_UNUSED) goto 999
        if (table(vid)%class > CLASSES_MAX) goto 999
        if (present(class)) class = table(vid)%class
        if (present(cid)) cid = table(vid)%cid
        return
    999 continue
        if (present(class)) class = VTB_CLASS_UNUSED
    end subroutine

    subroutine VarTableMore(vid, err)
        integer, intent(in):: vid
        logical, intent(out), optional:: err
        if (.not. allocated(table)) goto 999
        if (vid <= 0 .or. vid > size(table)) goto 999
        if (table(vid)%class <= VTB_CLASS_UNUSED) goto 999
        if (table(vid)%class > CLASSES_MAX) goto 999
        table(vid)%refcount = table(vid)%refcount + 1
        if (present(err)) err = .false.
        return
    999 continue
        if (present(err)) err = .true.
    end subroutine

    subroutine vartable_dump(vid)

        integer, intent(in):: vid
        character(10):: class
        if (.not. allocated(table)) return
        if (vid <= 0 .or. vid > size(table)) return
        select case(table(vid)%class)
        case(vtb_class_netcdf)
            class = 'netcdf'
        case(vtb_class_memory)
            class = 'memory'
        case default
            write(class, fmt="(i10)") table(vid)%class
        end select
        call DbgMessage('[vartable %d: class=%c cid=%d ref=%d]',  i=(/vid, table(vid)%cid, table(vid)%refcount/),  c1=trim(class))
        select case(table(vid)%class)
        case(vtb_class_netcdf)
            call DbgMessage('[%c]', c1=trim(tostring(an_variable(table(vid)%cid))))
        end select
    end subroutine

    subroutine entry_cleanup(vtb_entry)
        type(VAR_TABLE_ENTRY), intent(out):: vtb_entry(:)
        vtb_entry(:)%class = VTB_CLASS_UNUSED
        vtb_entry(:)%cid = -1
        vtb_entry(:)%refcount = 0
    end subroutine