socket timeout

Hi, I am attempting to timeout a socket_read() that is part of a handshaking process using socket_set_timeout(). Problem is it doesn't seem to work at all. If I switch off the handshaking write on the server side the read just sits there and doesn't time out at all. I have tried socket_set_timeout($socket,1) which I believe is 1 second and it never times out... Any thoughts on this would be most appreciated. Gareth