Diffstat (limited to 'man/io_uring.7')
1 files changed, 27 insertions, 9 deletions
diff --git a/man/io_uring.7 b/man/io_uring.7
index 972683b..dc76f42 100644
@@ -84,17 +84,35 @@ a read operation under
.BR io_uring ,
started with the
-which issues the equivalent of the
+operation, issues the equivalent of the
.BR read (2)
-would return as part of
+system call. In practice, it mixes the semantics of
+.BR pread (2)
+.BR preadv2 (2)
+in that it takes an explicit offset, and supports using -1 for the offset to
+indicate that the current file position should be used instead of passing in
+an explicit offset. See the opcode documentation for more details. Given that
+io_uring is an async interface,
+is never used for passing back error information. Instead,
-.BR read (2)
-would have returned if called directly,
-.BR io_uring .
+will contain what the equivalent system call would have returned in case
+of success, and in case of error
+.I -errno .
+For example, if the normal read system call would have returned -1 and set
+.B EINVAL ,
+.B -EINVAL .
+If the normal system call would have returned a read size of 1024, then
+would contain 1024.
.BR io_uring_enter (2)