Having a problem with rowcount

So I am using FreeTDS with Python and Sybase.py.

I am do a connection, cursor, execute a query and can fetch the results of the query.
All that works.

But when I go to change the code to check the rowcount for the status of the query, 
it is always -1.   Should it not be set to the number of rows in the query, which for my
query is like 50.

Here is the code (basically):

conn = Sybase.connect( cfg['dsn'], cfg['user'], cfg['pass'] )
cursor = conn.cursor()
cursor.execute ("SELECT id, queuetype FROM Components")

print "XXX: rowcount:", cursor.rowcount

while (1):
        row = cursor.fetchone()
        if row == None: break
        print row

connect.close()

Thanx
Nicholas