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| author | Michael Kerrisk <mtk.manpages@gmail.com> | 2019-07-29 20:51:22 +0200 |
|---|---|---|
| committer | Michael Kerrisk <mtk.manpages@gmail.com> | 2020-02-28 21:42:29 +0100 |
| commit | 112e0e60b73acb205b81cae07fa04fb1f45b0009 (patch) | |
| tree | abec8cc177bc6fd23eb4032d95c95561ad19d087 | |
| parent | cb1b0be6833d690a65b0ffeac864338a8cb9dbdf (diff) | |
| download | man-pages-112e0e60b73acb205b81cae07fa04fb1f45b0009.tar.gz | |
socket.7: Add more details on SO_SELECT_ERR_QUEUE
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
| -rw-r--r-- | man7/socket.7 | 44 |
1 files changed, 29 insertions, 15 deletions
diff --git a/man7/socket.7 b/man7/socket.7 index b824418705..aadbe6ab51 100644 --- a/man7/socket.7 +++ b/man7/socket.7 @@ -872,24 +872,38 @@ the number of packets dropped by the socket since its creation. .BR SO_SELECT_ERR_QUEUE " (since Linux 3.10)" .\" commit 7d4c04fc170087119727119074e72445f2bb192b .\" Author: Keller, Jacob E <jacob.e.keller@intel.com> -Makes poll adding +When this option is set on a socket, +an error condition on a socket causes notification not only via the +.I exceptfds +set of +.BR select (2). +Similarly, +.BR poll (2) +also returns a .B POLLPRI -when +whenever an .B POLLERR -event is returned. It does not affect wake up. +event is returned. +.\" It does not affect wake up. .IP -Background: The flag was added when waking up on -.B POLLERR -required requesting -.B POLLIN -or -.B POLLPRI. -After the commit 6e5d58fdc9bedd0255a8 ("skbuff: Fix not -waking applications when errors are enqueued"), introduced -in Linux 4.16, waking up on -.B POLLERR -does not require requesting other events. -The flag is kept only for backwards compatibility. +Background: this option was added when waking up on an error condition +occurred occured only via the +.IR readfds +and +.IR writefds +sets of +.BR select (2). +The option was added to allow monitoring for error conditions via the +.I exceptfds +argument without simultaneously having to receive notifications (via +.IR readfds ) +for regular data that can be read from the socket. +After changes in Linux 4.16, +.\" commit 6e5d58fdc9bedd0255a8 +.\" ("skbuff: Fix not waking applications when errors are enqueued") +the use of this flag to achieve the desired notifications +is no longer necessary. +This option is nevertheless retained for backwards compatibility. .TP .B SO_SNDBUF Sets or gets the maximum socket send buffer in bytes. |