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mirror of https://github.com/golang/go synced 2024-11-21 22:54:40 -07:00
go/doc/progs/fd.go
Rob Pike 293c8f8c65 casify tutorial examples
will bring document in line in a later CL, which may include revisiting some of the names

R=rsc
DELTA=58  (0 added, 0 deleted, 58 changed)
OCL=22906
CL=22908
2009-01-15 17:54:07 -08:00

63 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 fd
import (
"os";
"syscall";
)
export type FD struct {
fildes int64; // file descriptor number
name string; // file name at Open time
}
func newFD(fd int64, name string) *FD {
if fd < 0 {
return nil
}
return &FD{fd, name}
}
export var (
Stdin = newFD(0, "/dev/stdin");
Stdout = newFD(1, "/dev/stdout");
Stderr = newFD(2, "/dev/stderr");
)
export func Open(name string, mode int64, perm int64) (fd *FD, err *os.Error) {
r, e := syscall.open(name, mode, perm);
return newFD(r, name), os.ErrnoToError(e)
}
func (fd *FD) Close() *os.Error {
if fd == nil {
return os.EINVAL
}
r, e := syscall.close(fd.fildes);
fd.fildes = -1; // so it can't be closed again
return nil
}
func (fd *FD) Read(b []byte) (ret int, err *os.Error) {
if fd == nil {
return -1, os.EINVAL
}
r, e := syscall.read(fd.fildes, &b[0], int64(len(b)));
return int(r), os.ErrnoToError(e)
}
func (fd *FD) Write(b []byte) (ret int, err *os.Error) {
if fd == nil {
return -1, os.EINVAL
}
r, e := syscall.write(fd.fildes, &b[0], int64(len(b)));
return int(r), os.ErrnoToError(e)
}
func (fd *FD) String() string {
return fd.name
}