[LibPQ] Trying PQconnectStart: it doesn't seem to connect

Hi,
i'm a python/c developer and i need an asynchronous (python) interface to communicate with a database. I like PostgreSQL so i'm trying to write a mock-up for a python extension module to use LibPQ in my asynchronous programs.

I've started to study the docs about libpq just yesterday, so if i mistake something please correct me.
I'm writing the connection function, using the api PQconnectStart but verifing the status of this call i get that the condition PQstatus(connection) != CONNECTION_OK (the connection must return CONNECTION_OK) is failed so my program exits. Using instead of it the PQconnectiondb all work as expected, but not using this api.

Can someone tell me what i wrong? And if you know some resource that explains with an example how i should to verify the connection during the select/poll, would be appreciated.

Thank you,
Alex.
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Alessandro A.