io: clarify SeekEnd offset value
fixes #53474
Change-Id: I14c3dc800dc27233630a54592328bb0df1bbaa5d
GitHub-Last-Rev: 46f93cfbd41c1b3274b570744f18d08e7759eb1e
GitHub-Pull-Request: golang/go#53505
Reviewed-on: https://go-review.googlesource.com/c/go/+/413614
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Emmanuel Odeke <emmanuel@orijtech.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Emmanuel Odeke <emmanuel@orijtech.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
diff --git a/src/io/io.go b/src/io/io.go
index db88125..9d4c0d2 100644
--- a/src/io/io.go
+++ b/src/io/io.go
@@ -111,7 +111,8 @@
// interpreted according to whence:
// SeekStart means relative to the start of the file,
// SeekCurrent means relative to the current offset, and
-// SeekEnd means relative to the end.
+// SeekEnd means relative to the end
+// (for example, offset = -2 specifies the penultimate byte of the file).
// Seek returns the new offset relative to the start of the
// file or an error, if any.
//
