epoll_wait.2: Clarify the behavior when epoll_wait()-ing on an empty interest list

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

diff --git a/man2/epoll_wait.2 b/man2/epoll_wait.2
index a6d37425c14e845f243ad5fe4362a19405d7bb1a..5ec69ef00aa9556fac6ac687700021f97e137ce0 100644 (file)
--- a/man2/epoll_wait.2
+++ b/man2/epoll_wait.2
@@ -217,12 +217,15 @@ it will cause the
 .BR epoll_wait ()
 call to unblock.
 .PP
-For a discussion of what may happen if a file descriptor in an
-.B epoll
-instance being monitored by
+Note that it is possible to call
 .BR epoll_wait ()
-is closed in another thread, see
-.BR select (2).
+on an
+.B epoll
+instance whose interest list is currently empty
+(or whose interest list becomes empty because file descriptors are closed
+or removed from the interest in another thread).
+The call will block until some file descriptor is later added to the
+interest list (in another thread) and that file descriptor becomes ready.
 .SH BUGS
 In kernels before 2.6.37, a
 .I timeout