- * a) POLLRDNORM and POLLIN are set if the socket's receive queue is non-empty
- * or if a connection-oriented socket is does not have an active connection
- * (i.e. a read operation will not block).
- * b) POLLOUT is set except when a socket's connection has been terminated
- * (i.e. a write operation will not block).
- * c) POLLHUP is set when a socket's connection has been terminated.
- *
- * IMPORTANT: The fact that a read or write operation will not block does NOT
- * imply that the operation will succeed!
+ *
+ * socket state flags set
+ * ------------ ---------
+ * unconnected no read flags
+ * no write flags
+ *
+ * connecting POLLIN/POLLRDNORM if ACK/NACK in rx queue
+ * no write flags
+ *
+ * connected POLLIN/POLLRDNORM if data in rx queue
+ * POLLOUT if port is not congested
+ *
+ * disconnecting POLLIN/POLLRDNORM/POLLHUP
+ * no write flags
+ *
+ * listening POLLIN if SYN in rx queue
+ * no write flags
+ *
+ * ready POLLIN/POLLRDNORM if data in rx queue
+ * [connectionless] POLLOUT (since port cannot be congested)
+ *
+ * IMPORTANT: The fact that a read or write operation is indicated does NOT
+ * imply that the operation will succeed, merely that it should be performed
+ * and will not block.