Simple compile question

I just installed pgsql this morning and already encountered some difficulties. How do I compile a C/C++ client application with pgsql? Here's what I do:

gcc -c -I/usr/local/pgsql/include sample.cpp

and I get:

aggregate 'PGconn conn' has incomplete type and cannot be initialized
aggregate 'PGresult res' has incomplete type and cannot be initialized

The libpq-fe.h file *is* in /usr/local/pgsql/include

What other include files am I missing?

Also, a lot of messages seem to indicate that there is sample code under the src/ dir. Where is this? It is not under /usr/local/pgsql. Did I miss a step in the install?

thanks,
Stephen