xnu-2782.20.48.tar.gz

[apple/xnu.git] / bsd / sys / event.h

diff --git a/bsd/sys/event.h b/bsd/sys/event.h
index 66efc61b012cce808b79076cbfd4d1eaf0fd4db9..44cef5438af4fb00afefeb29a56aabd303fd1b32 100644 (file)
--- a/bsd/sys/event.h
+++ b/bsd/sys/event.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003-2012 Apple Inc. All rights reserved.
+ * Copyright (c) 2003-2015 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
@@ -177,14 +177,20 @@ struct kevent64_s {
  * (which always returns true for regular files - regardless of the amount
  * of unread data in the file).
  *
- * On input, EV_OOBAND specifies that only OOB data should be looked for.
- * The returned data count is the number of bytes beyond the current OOB marker.
+ * On input, EV_OOBAND specifies that filter should actively return in the
+ * presence of OOB on the descriptor. It implies that filter will return
+ * if there is OOB data available to read OR when any other condition
+ * for the read are met (for example number of bytes regular data becomes >=
+ * low-watermark).
+ * If EV_OOBAND is not set on input, it implies that the filter should not actively
+ * return for out of band data on the descriptor. The filter will then only return
+ * when some other condition for read is met (ex: when number of regular data bytes
+ * >=low-watermark OR when socket can't receive more data (SS_CANTRCVMORE)).
  *
- * On output, EV_OOBAND indicates that OOB data is present
+ * On output, EV_OOBAND indicates the presence of OOB data on the descriptor.
  * If it was not specified as an input parameter, then the data count is the
- * number of bytes before the current OOB marker. If at the marker, the
- * data count indicates the number of bytes available after it.  In either
- * case, it's the amount of data one could expect to receive next.
+ * number of bytes before the current OOB marker, else data count is the number
+ * of bytes beyond OOB marker.
  */
 #define EV_POLL        EV_FLAG0
 #define EV_OOBAND      EV_FLAG1
@@ -474,7 +480,7 @@ extern int  knote_link_wait_queue(struct knote *kn, struct wait_queue *wq, wait_q
 extern int     knote_unlink_wait_queue(struct knote *kn, struct wait_queue *wq, wait_queue_link_t *wqlp);
 extern void    knote_fdclose(struct proc *p, int fd);
 extern void    knote_markstayqueued(struct knote *kn);
-
+extern void    knote_clearstayqueued(struct knote *kn);
 #endif /* !KERNEL_PRIVATE */
 
 #else  /* KERNEL */