Cannot login, with C/C++ program

I have written a C/C++ program that trys to log into a local
PostgreSQL database. Here is the code:

pg_conn = PQconnectdb(
"hostaddr = '127.0.0.1' port = '' dbname = 'TBDB' user = 'sysdba'
password = 'stelmo777' connect_timeout = '10'");
if (!pg_conn)
{
return false;
}
if (PQstatus(pg_conn) != CONNECTION_OK)
{
return false; // <- execution reaches here.

I checked the database, user and password by logging in with psql.
What could be wrong?