pg_version() returns an array with the client, protocol and server version. Protocol and server versions are only avaliable if PHP was compiled with PostgreSQL 7.4 or later.
For more detailed server information, use pg_parameter_status().
PostgreSQL database connection resource. When connection is not present, the default connection is used. The default connection is the last connection made by pg_connect() or pg_pconnect().
Returns an array with client, protocol and server_version keys and values (if available). Returns FALSE on error or invalid connection.