Persistent connections in PHP with PDO

Has anyone played around with the new PHP ODO drivers and been able to
successfully set up an object using persistent connections? I tried to
follow the documentation in the PHP manual to send an array in the PDO
constructor but receive a warning message that the underlying driver
does not support this. I mucked around in the source code for the driver
in the PHP source tree and it appears there is no facility in the driver
for sending such options, which leaves me to wonder if you simply set
the php.ini value to support persistent connections that would be all
you need to do? Can anyone shed any light on this problem? There seems
to be little if any documentation on this.

Thanks in advance.

Alan