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go/doc/progs/file.go
Rob Pike e45b58fe96 os: change the type of permissions argument for Open etc. to uint32.
Besides being more correct, it protects against people accidentally
exchanging the permission and open mode arguments to Open.

R=rsc
CC=golang-dev
https://golang.org/cl/1904045
2010-08-04 08:34:52 +10:00

75 lines
1.3 KiB
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 int // file descriptor number
name string // file name at Open time
}
func newFile(fd int, name string) *File {
if fd < 0 {
return nil
}
return &File{fd, name}
}
var (
Stdin = newFile(0, "/dev/stdin")
Stdout = newFile(1, "/dev/stdout")
Stderr = newFile(2, "/dev/stderr")
)
func Open(name string, mode int, perm uint32) (file *File, err os.Error) {
r, e := syscall.Open(name, mode, perm)
if e != 0 {
err = os.Errno(e)
}
return newFile(r, name), err
}
func (file *File) Close() os.Error {
if file == nil {
return os.EINVAL
}
e := syscall.Close(file.fd)
file.fd = -1 // 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) {
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) {
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
}