Trim not working (PostgreSQL 9.1.2 on Win64) - Mailing list pgsql-general

I've a select with the following expression:

select trim(both ' ' from substring(rslinha2 from 5 for position('(-)' in rslinha2)-6))
           from ...

problem is that the spaces are not being removed from either side. What would be wrong?

Thanks for your help,