@chai2010 because you don't append last backslash for Join().

package main

import (
    "fmt"
    "log"
    "os"
    "path/filepath"
)

func main() {
    f, err := os.Open(`C:\`)
    if err != nil {
        log.Fatal("os.Open:", err)
    }
    defer f.Close()

    names, err := f.Readdirnames(-1)
    if err != nil {
        log.Fatal("f.Readdirnames:", err)
    }

    for i, s := range names {
        fmt.Println(i, s)
        filename := filepath.Join(`C:\`, s)
        fileInfo, err := os.Lstat(filename)
        if err != nil {
            log.Fatal("os.Lstat:", err)
        }
        fmt.Println("\t", fileInfo.IsDir())
    }
}

But it will be fail with some system-file on C:\

2015/12/29 20:57:39 os.Lstat:GetFileAttributesEx C:\hiberfil.sys: The process cannot access the file because it is being used by another process.
exit status 1

@mattn thanks.
I want to say the os.Lstat can't process some system-file.
I need use mklink /J dst d: to mount some disk to subdir, but the filepath.Walk failed, if the mounted dir has some system-file(such as $Recycle.Bin).

On my windows10, my modified code above display like below.

0 $Recycle.Bin
     true
1 $WINDOWS.~BT
     true
2 $Windows.~WS
     true
3 bootmgr
     false
4 BOOTNXT
     false
5 dev
     true
6 Documents and Settings
     true
7 hiberfil.sys
2015/12/29 22:20:22 os.Lstat:GetFileAttributesEx C:\hiberfil.sys: The process cannot access the file because it is being used by another process.
exit status 1

So $Recycle.Bin is not related on this issue, I guess.

@chai2010, what do you think the problem is?

I think the problem is that os.Open("C:") currently opens root directory of C: (C:\). I think we should change the code so it opens "current directory" on C: (C:.), just like "dir c:" command does. What do you think?

I suspect if you run your example program from root directory on C:, it will run just fine.

Alex

@mattn I has the same error as you: os.Lstat failed on C:\hiberfil.sys.

@alexbrainman I donot know the reason. I think there are three problems:

1. C:\ is not same as C:
2. os.Lstat failed on C:\hiberfil.sys, I donot know the reason.
3. filepath.Walk failed: C:\$Recycle.Bin\S-1-5-21-1654714224-3836454192-1760979379-1000\$R52OC9K\System Volume Information: Access is denied.

The filepath.Walk test code:

func main() {
    const root = `C:\`
    err := filepath.Walk(root, func(path string, fi os.FileInfo, err error) error {
        if err != nil {
            return err
        }
        fmt.Printf("filepath.Walk: path = %s; isdir = %v\n", path, fi.IsDir())
        return nil
    })
    if err != nil {
        log.Fatal("filepath.Walk:", err)
    }
    fmt.Println("Done")
}

CL https://golang.org/cl/18184 mentions this issue.