round returns -0

I'm taking an standard deviation of a population and subtracting it from
the average of the same population and rounding the result. Sometimes
that result is negative and rounding it returns (or shows up as) a
negative zero (-0) in a SELECT.

basically:
SELECT
client_name, avg(rpt_cnt),
stddev_pop(rpt_cnt),
round(avg(rpt_cnt) - stddev_pop(rpt_cnt))
from client_counts
group by client_name

and what I sometimes get is :
client_name | a dp number | a dp number | -0

In postgresql-world, is -0 = 0? Can I use that negative 0 in further
calculations without fear? Is this a bug?

pg version is 9.2
OS is Windows 2003.

Thanks,

Wade Dare
"Committed to striving for an effort to try..."