text: // +build windows
  
  package winio
  
  import (
  	"os"
  	"runtime"
  	"syscall"
  	"unsafe"
  )
  
  //sys getFileInformationByHandleEx(h syscall.Handle, class uint32, buffer *byte, size uint32) (err error) = GetFileInformationByHandleEx
  //sys setFileInformationByHandle(h syscall.Handle, class uint32, buffer *byte, size uint32) (err error) = SetFileInformationByHandle
  
  const (
  	fileBasicInfo = 0
  	fileIDInfo    = 0x12
  )
  
  // FileBasicInfo contains file access time and file attributes information.
  type FileBasicInfo struct {
  	CreationTime, LastAccessTime, LastWriteTime, ChangeTime syscall.Filetime
  	FileAttributes                                          uint32
  	pad                                                     uint32 // padding
  }
  
  // GetFileBasicInfo retrieves times and attributes for a file.
  func GetFileBasicInfo(f *os.File) (*FileBasicInfo, error) {
  	bi := &FileBasicInfo{}
  	if err := getFileInformationByHandleEx(syscall.Handle(f.Fd()), fileBasicInfo, (*byte)(unsafe.Pointer(bi)), uint32(unsafe.Sizeof(*bi))); err != nil {
  		return nil, &os.PathError{Op: "GetFileInformationByHandleEx", Path: f.Name(), Err: err}
  	}
  	runtime.KeepAlive(f)
  	return bi, nil
  }
  
  // SetFileBasicInfo sets times and attributes for a file.
  func SetFileBasicInfo(f *os.File, bi *FileBasicInfo) error {
  	if err := setFileInformationByHandle(syscall.Handle(f.Fd()), fileBasicInfo, (*byte)(unsafe.Pointer(bi)), uint32(unsafe.Sizeof(*bi))); err != nil {
  		return &os.PathError{Op: "SetFileInformationByHandle", Path: f.Name(), Err: err}
  	}
  	runtime.KeepAlive(f)
  	return nil
  }
  
  // FileIDInfo contains the volume serial number and file ID for a file. This pair should be
  // unique on a system.
  type FileIDInfo struct {
  	VolumeSerialNumber uint64
  	FileID             [16]byte
  }
  
  // GetFileID retrieves the unique (volume, file ID) pair for a file.
  func GetFileID(f *os.File) (*FileIDInfo, error) {
  	fileID := &FileIDInfo{}
  	if err := getFileInformationByHandleEx(syscall.Handle(f.Fd()), fileIDInfo, (*byte)(unsafe.Pointer(fileID)), uint32(unsafe.Sizeof(*fileID))); err != nil {
  		return nil, &os.PathError{Op: "GetFileInformationByHandleEx", Path: f.Name(), Err: err}
  	}
  	runtime.KeepAlive(f)
  	return fileID, nil
  }
  