diff --git a/src/os/file_plan9.go b/src/os/file_plan9.go
index feca8630bea..3a0b774aa2d 100644
--- a/src/os/file_plan9.go
+++ b/src/os/file_plan9.go
@@ -133,7 +133,8 @@ func openFileNolog(name string, flag int, perm FileMode) (*File, error) {
 }
 
 // Close closes the File, rendering it unusable for I/O.
-// It returns an error, if any.
+// On files that support SetDeadline, any pending I/O operations will
+// be canceled and return immediately with an error.
 func (f *File) Close() error {
 	if err := f.checkValid("close"); err != nil {
 		return err
diff --git a/src/os/file_unix.go b/src/os/file_unix.go
index e0b8119d968..4f80553a18f 100644
--- a/src/os/file_unix.go
+++ b/src/os/file_unix.go
@@ -217,7 +217,8 @@ func openFileNolog(name string, flag int, perm FileMode) (*File, error) {
 }
 
 // Close closes the File, rendering it unusable for I/O.
-// It returns an error, if any.
+// On files that support SetDeadline, any pending I/O operations will
+// be canceled and return immediately with an error.
 func (f *File) Close() error {
 	if f == nil {
 		return ErrInvalid
diff --git a/src/os/file_windows.go b/src/os/file_windows.go
index a17c6e2ac33..8901eadd256 100644
--- a/src/os/file_windows.go
+++ b/src/os/file_windows.go
@@ -171,7 +171,8 @@ func openFileNolog(name string, flag int, perm FileMode) (*File, error) {
 }
 
 // Close closes the File, rendering it unusable for I/O.
-// It returns an error, if any.
+// On files that support SetDeadline, any pending I/O operations will
+// be canceled and return immediately with an error.
 func (file *File) Close() error {
 	if file == nil {
 		return ErrInvalid