PgConnection type_info function

I cannot link with postgreSQL. I had done so on a linux machine, only linked
to one library "pq++" and succeeded. Now I try it on NetBSD, I cannot even
if I add 3 other libraries: "pq, ecpg, pgeasy" found in
/usr/local/pgsql/lib. Here are the messages:
-----------------------------------------------------------
g++ -L/usr/local/pgsql/lib -lpq++ -lpq -lecpg -lpgeasy -o problog.cgi
problog.o xutils.o xpgsql.o prob.o
problog.o: Undefined symbol `PgConnection type_info function' referenced
from text segment
problog.o: Undefined symbol `PgConnection type_info node' referenced from
text segment
xpgsql.o: Undefined symbol `PgConnection type_info function' referenced from
text segment
xpgsql.o: Undefined symbol `PgConnection type_info node' referenced from
text segment
prob.o: Undefined symbol `PgConnection type_info function' referenced from
text segment
prob.o: Undefined symbol `PgConnection type_info node' referenced from text
segment
collect2: ld returned 1 exit status
*** Error code 1
-----------------------------------------------------------

I wrote a most simple test program, the same problem while linking.

Could anybody help me? Thanks!