unsafe: document use of &^ to round/align pointers
Follow-up to CL 27156
Change-Id: I4f1cfced2dced9c9fc8a05bbc00ec4229e85c5c9
Reviewed-on: https://go-review.googlesource.com/27314
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/src/unsafe/unsafe.go b/src/unsafe/unsafe.go
index 8f43e72..0b59ff2 100644
--- a/src/unsafe/unsafe.go
+++ b/src/unsafe/unsafe.go
@@ -76,8 +76,10 @@
// // equivalent to e := unsafe.Pointer(&x[i])
// e := unsafe.Pointer(uintptr(unsafe.Pointer(&x[0])) + i*unsafe.Sizeof(x[0]))
//
-// It is valid both to add and to subtract offsets from a pointer in this way,
-// but the result must continue to point into the original allocated object.
+// It is valid both to add and to subtract offsets from a pointer in this way.
+// It is also valid to use &^ to round pointers, usually for alignment.
+// In all cases, the result must continue to point into the original allocated object.
+//
// Unlike in C, it is not valid to advance a pointer just beyond the end of
// its original allocation:
//
