code review 5307066: non-pkg: gofix -r error

doc/progs/file_windows.go

 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 package file
 
 import (
         "os"
         "syscall"
 )
 
 type File struct {
         fd   syscall.Handle // file descriptor number
         name string         // file name at Open time
 }
 
 func newFile(fd syscall.Handle, name string) *File {
         if fd == ^syscall.Handle(0) {
                 return nil
         }
         return &File{fd, name}
 }
 
 var (
         Stdin  = newFile(syscall.Stdin, "/dev/stdin")
         Stdout = newFile(syscall.Stdout, "/dev/stdout")
         Stderr = newFile(syscall.Stderr, "/dev/stderr")
 )
 
-func OpenFile(name string, mode int, perm uint32) (file *File, err os.Error) {
+func OpenFile(name string, mode int, perm uint32) (file *File, err error) {
         r, e := syscall.Open(name, mode, perm)
         if e != 0 {
                 err = os.Errno(e)
         }
         return newFile(r, name), err
 }
 
 const (
         O_RDONLY = syscall.O_RDONLY
         O_RDWR   = syscall.O_RDWR
         O_CREATE = syscall.O_CREAT
         O_TRUNC  = syscall.O_TRUNC
 )
 
-func Open(name string) (file *File, err os.Error) {
+func Open(name string) (file *File, err error) {
         return OpenFile(name, O_RDONLY, 0)
 }
 
-func Create(name string) (file *File, err os.Error) {
+func Create(name string) (file *File, err error) {
         return OpenFile(name, O_RDWR|O_CREATE|O_TRUNC, 0666)
 }
 
-func (file *File) Close() os.Error {
+func (file *File) Close() error {
         if file == nil {
                 return os.EINVAL
         }
         e := syscall.Close(file.fd)
         file.fd = syscall.InvalidHandle // so it can't be closed again
         if e != 0 {
                 return os.Errno(e)
         }
         return nil
 }
 
-func (file *File) Read(b []byte) (ret int, err os.Error) {
+func (file *File) Read(b []byte) (ret int, err error) {
         if file == nil {
                 return -1, os.EINVAL
         }
         r, e := syscall.Read(file.fd, b)
         if e != 0 {
                 err = os.Errno(e)
         }
         return int(r), err
 }
 
-func (file *File) Write(b []byte) (ret int, err os.Error) {
+func (file *File) Write(b []byte) (ret int, err error) {
         if file == nil {
                 return -1, os.EINVAL
         }
         r, e := syscall.Write(file.fd, b)
         if e != 0 {
                 err = os.Errno(e)
         }
         return int(r), err
 }
 
 func (file *File) String() string {
         return file.name
 }