closed polygons from binary raster

[Allan B Branscomb]

I have a binary raster map and want to produce from it a closed polygons
bounding the clumps of non-zero cells.

I run r.poly and, as its documentation states, it produces EDGES.  In practice
this has meant that sometimes I get closed polygons (the first vertex repeated
as the last one) and sometimes I get lines.  The resultant vector map is a
mixture of polylines and polygons.

Is there any other program available in GRASS that can reliably produce closed
polygons, or is there some better way to pre-process my binary raster map
so r.poly will?

thank you.

allan