Re: [PATCH] document FIONREAD on pipe
From: Michael Kerrisk (man-pages) <hidden>
Date: 2016-09-25 10:10:28
Subsystem:
the rest · Maintainer:
Linus Torvalds
Possibly related (same subject, not in this thread)
- 2016-09-26 · Re: [PATCH] document FIONREAD on pipe · Patrick McLean <hidden>
- 2016-09-23 · [PATCH] document FIONREAD on pipe · Patrick McLean <hidden>
Hello Patrick On 09/24/2016 12:17 AM, Patrick McLean wrote:
The FIONREAD ioctl can be used on a pipe to get the current amount of data in the pipe. This ioctl is currently only documented in tty_ioctl (4). This adds a blurb to the pipe(7) man page about this ioctl.
Thanks for the patch. In the end, I wrote something more extensive. See below. Cheers, Michael
diff --git a/man7/pipe.7 b/man7/pipe.7
index 9977acc..b6a3007 100644
--- a/man7/pipe.7
+++ b/man7/pipe.7@@ -143,6 +143,21 @@ operations. See .BR fcntl (2) for more information. + +The following +.BR ioctl (2) +operation, which can be applied to a file descriptor +that refers to either end of a pipe, +places a count of the number of unread bytes in the pipe in the +.I int +buffer pointed to by the final argument of the call: + + ioctl(fd, FIONREAD, &nbytes); + +The +.B FIONREAD +operation is not specified in any standard, +but is provided on many implementations.
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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