net: document that File reverts connection to blocking mode.
Fixes #2458.
R=mikioh.mikioh, rsc
CC=golang-dev
https://golang.org/cl/6869054
diff --git a/src/pkg/net/net.go b/src/pkg/net/net.go
index f60c1e4c..a3d1759 100644
--- a/src/pkg/net/net.go
+++ b/src/pkg/net/net.go
@@ -197,9 +197,13 @@
return setWriteBuffer(c.fd, bytes)
}
-// File returns a copy of the underlying os.File, set to blocking mode.
+// File sets the underlying os.File to blocking mode and returns a copy.
// It is the caller's responsibility to close f when finished.
// Closing c does not affect f, and closing f does not affect c.
+//
+// The returned os.File's file descriptor is different from the connection's.
+// Attempting to change properties of the original using this duplicate
+// may or may not have the desired effect.
func (c *conn) File() (f *os.File, err error) { return c.fd.dup() }
// An Error represents a network error.
