From a1ae3a05363050dc4bd809c367ba764b5d11e811 Mon Sep 17 00:00:00 2001
From: Brad Fitzpatrick <bradfitz@golang.org>
Date: Tue, 15 Apr 2014 17:14:03 -0700
Subject: [PATCH] io: document that a Writer must not write to p

Per golang-nuts question. Writing to p breaks
other writers (e.g. io.MultiWriter).

Make this explicit.

LGTM=gri, r, rsc
R=r, rsc, gri, joshlf13
CC=golang-codereviews
https://golang.org/cl/87780046
---
 src/pkg/io/io.go | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/pkg/io/io.go b/src/pkg/io/io.go
index f7073ffc06..022fdb6764 100644
--- a/src/pkg/io/io.go
+++ b/src/pkg/io/io.go
@@ -74,6 +74,7 @@ type Reader interface {
 // It returns the number of bytes written from p (0 <= n <= len(p))
 // and any error encountered that caused the write to stop early.
 // Write must return a non-nil error if it returns n < len(p).
+// Write must not modify the slice data, even temporarily.
 type Writer interface {
 	Write(p []byte) (n int, err error)
 }