viewing the slaves which are connected to a master in streaming replication

I've got a postgres-9.2.x cluster, doing streaming replication to
several hot standby servers.  I'd like to be able to query the master
to see the hostname or IP address of each connected streaming
replication standby server.

I know that I can view which servers are connected to the master by
looking at 'ps' output, grepping for 'wal sender process' for the IP
address of each standby server that is currently connected.  However,
I was hoping that there was a more elegant method for obtaining this
information?  I've googled a bit, and haven't found any SQL magic to
do it, but perhaps I'm just not searching for the right thing?

thanks