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From: Alois Wohlschlager <[email protected]>
To: [email protected]
Subject: [PATCH] io_uring_enter(2): Clarify how to read from and write to  non-seekable files
Date: Mon, 31 May 2021 14:38:15 +0200	[thread overview]
Message-ID: <2191760.Ec4jsOL7QN@genesis> (raw)

IORING_OP_READ* and IORING_OP_WRITE* all take a file offset. These
operations can still be used with non-seekable files, as long as the
offset is set to zero.

Signed-off-by: Alois Wohlschlager <[email protected]>
---
 man/io_uring_enter.2 | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/man/io_uring_enter.2 b/man/io_uring_enter.2
index 5b498e5..dd3c962 100644
--- a/man/io_uring_enter.2
+++ b/man/io_uring_enter.2
@@ -195,6 +195,9 @@ Vectored read and write operations, similar to
 .BR preadv2 (2)
 and
 .BR pwritev2 (2).
+If the file is not seekable,
+.I off
+must be set to zero.

 .TP
 .B IORING_OP_READ_FIXED
@@ -588,6 +591,10 @@ contains the buffer in question,
 contains the length of the IO operation, and
 .I offs
 contains the read or write offset. If
+.I fd
+does not refer to a seekable file,
+.I off
+must be set to zero. If
 .I offs
 is set to -1, the offset will use (and advance) the file position, like the
 .BR read(2)
--
2.31.1



             reply	other threads:[~2021-05-31 12:38 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-31 12:38 Alois Wohlschlager [this message]
2021-06-01 17:10 ` [PATCH] io_uring_enter(2): Clarify how to read from and write to non-seekable files Jens Axboe

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