Provided by:
linux-doc-2.6.15_2.6.15-23.39_all 
NAME
datagram_poll - generic datagram poll
SYNOPSIS
unsigned int datagram_poll (struct file * file, struct socket * sock,
poll_table * wait);
ARGUMENTS
file file struct
sock socket
wait poll table
DATAGRAM POLL
Again totally generic. This also handles sequenced packet sockets
providing the socket receive queue is only ever holding data ready to
receive.
NOTE
when you _don’t_ use this routine for this protocol, and you use a
different write policy from sock_writeable then please supply your own
write_space callback.