(stringlist_handle) CellsHandle(cellname,
depth)
This function returns a handle to a list of subcell names found in
cellname, to the given depth. If cellname is null
or empty, the current cell is assumed. The depth is the search
depth, which can be an integer which sets the maximum depth to search
(0 means search cellname only and return its subcell names, 1
means search cellname plus its subcells, etc., and a negative
integer sets the depth to search the entire hierarchy). This argument
can also be a string starting with `a' such as "a" or "all" which indicates to search the entire hierarchy. The listing
order is as a tree, with a subcell listed followed by the descent into
that subcell.
With ``all'' passed, the output is similar to that of the InitGen function, except that the top-level cell name is not listed,
and duplicate entries are not removed (ListUnique can be called
to remove duplicate names).