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
next 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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