man/io_uring_prep_close_direct.3: note on IOSQE_FIXED_FILE

The application must not set IOSQE_FIXED_FILE for closing a direct descriptor, the helper will correctly assign the direct descriptor index to close. Link: #1325 Signed-off-by: Jens Axboe <[email protected]>
axboe · Jan 7, 2025 · 76bb80a · 76bb80a
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commit 76bb80a
Showing 1 changed file with 6 additions and 1 deletion.
diff --git a/man/io_uring_prep_close.3 b/man/io_uring_prep_close.3
@@ -30,7 +30,12 @@ For a direct descriptor close request, the offset is specified by the
 argument instead of the
 .IR fd .
 This is identical to unregistering the direct descriptor, and is provided as
-a convenience.
+a convenience. Note that even though it's closing a direct descriptor, the
+application must not set
+.B IOSQE_FIXED_FILE
+on the SQE. Otherwise the request will complete with
+.B -EBADF
+as the result.
 
 These functions prepare an async
 .BR close (2)