Libpq: PQftype, PQfsize

Hi,

I have a test table with varchar(40) column. After executing the following
query: 
select substr(fc,1,2) from test
PQftype returns for the result column PG_TYPE_TEXT and PQfsize returns -1. 
Is it the expected behaviour? The most suprising for me is PQfsize. 
Tested on PostgreSQL 8.4, 32-bit Windows.
Thank you in advance for explanations.

Bozena