libgo: Update to weekly.2012-03-13.

From-SVN: r186023

1 files changed, 7 insertions, 0 deletions

diff --git a/libgo/go/io/io.go b/libgo/go/io/io.go
index 7074834..54bf159 100644
--- a/libgo/go/io/io.go
+++ b/libgo/go/io/io.go
@@ -173,6 +173,13 @@ type ReaderAt interface {
 // at offset off.  It returns the number of bytes written from p (0 <= n <= len(p))
 // and any error encountered that caused the write to stop early.
 // WriteAt must return a non-nil error if it returns n < len(p).
+//
+// If WriteAt is writing to a destination with a seek offset,
+// WriteAt should not affect nor be affected by the underlying
+// seek offset.
+//
+// Clients of WriteAt can execute parallel WriteAt calls on the same
+// destination if the ranges do not overlap.
 type WriterAt interface {
 	WriteAt(p []byte, off int64) (n int, err error)
 }