Not PHP 5.3.6 but 5.2.6

Seems like the problem is the resource $conn and not the function pg_connection_status().

It's like the function couldn't use that resource to do what it must to return the expected value.

If the resource is not a valid PostgreSql link resource, pg_connection_status() return PGSQL_CONNECTION_BAD but in my case it generate a warning more. I'm catching the warning with a personalized error handler but I prefer keep the php error handler with a error_reporting() set to E_ALL. Is There is a solution to verify my connection without generate a warning ? Thanks.

You are right. I have just tested it in a postgresql server right now and I don't get a warning from pg_connection_status(). Still, I am using version 5.3.3 of PHP.

But a strange behavior, is that my pg_connection_status returns boolean FALSE if resource is not valid, which is different from 0 of PGSQL_CONNECTION_BAD:

$valid_resource = pg_connect('host=~ valid string here');
$invalid_resource = null;

var_dump( pg_connection_status( $valid_resource ) ); // int(0) as expected
var_dump( pg_connection_status( $invalid_resource ) ); // bool(false)
var_dump( PGSQL_CONNECTION_BAD ); // int(1) different from bool(false)
var_dump( PGSQL_CONNECTION_OK ); // int(0) as expected

Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to report
a bug at http://bugs.php.net/how-to-report.php

WHen the connection parameter is not a valid resource, the error comes from param 
validation...