* VB-CODE (2)
Tip 142: Determining Whether the Operating System Supports Long File 
Names

August 6, 1995

Abstract
While developing an application in Microsoft® Visual Basic®, you may 
need to allow
your user to use long file names. This article explains how you can 
determine
whether the operating system supports long file names.

Using Long File Names in Windows 95
The Microsoft® Windows® 95 operating system lets you use long file 
names when
creating directories and files. Under other operating systems, you 
might store
your word processing files in a directory called C:\DOCS. Under Windows 
95,
however, you can specify the directory name as C:\Documents for Legal 
Department.
Using long file names such as this can make your file system easier to 
navigate.

To determine whether your current operating system supports long file 
names, you
can use the GetVolumeInformation function in Visual Basic®. To use this 
function,
include the following Declare statement in the General Declarations 
section of
your project (note that the Declare statement must be typed as a single 
line of
code):

Private Declare Function GetVolumeInformation Lib "kernel32" Alias
   "GetVolumeInformationA" (ByVal lpRootPathName As String, ByVal
   lpVolumeNameBuffer As String, ByVal nVolumeNameSize As Long,
   lpVolumeSerialNumber As Long, lpMaximumComponentLength As Long,
   lpFileSystemFlags As Long, ByVal lpFileSystemNameBuffer As String,
   ByVal nFileSystemNameSize As Long) As Long

The GetVolumeInformation function retrieves information about the disk 
and/or
file system used on the specified disk drive. This function requires 
eight
arguments, as follows:

lpRootPathName            A string containing the name of the disk's 
root
                          directory.
lpVolumeNameBuffer        A string that will hold the disk's volume 
name.
nVolumeNameSize           A long value containing the size of 
lpVolumeNameBuffer.
lpVolumeSerialNumber      A long value that will hold the volume serial 
number.
lpMaximumComponentLength  A long value containing the maximum length of 
a file
                          name component.
lpFileSystemFlags         A long value containing the maximum length of 
a file
                          name component. A combination of the 
following flags
                          is used:
   FS_CASE_IS_PRESERVED	      File system preserves the case of file 
names when
                              saved to disk.
   FS_CASE_SENSITIVE	      File system supports case-sensitive file 
names.
   FS_UNICODE_STORED_ON_DISK  File system supports Unicode in file 
names.
   FS_PERSISTENT_ACLS         File system preserves and enforces access 
control
                              lists (ACLs).
lpFileSystemNameBuffer    A string to hold the file system's name (FAT, 
HPFS, or
                          NTFS).
nFileSystemNameSize       A long value containing the length of
                          lpFileSystemNameBuffer.

After the program calls the GetVolumeInformation function, a value of 
True is
returned if the function was successful and all information about the 
disk/file
system was retrieved. A value of False is returned if the function was 
not
successful.
After you have executed the GetVolumeInformation function, it returns 
the maximum
component length of a file name. An ordinary MS-DOS® file name (such as
COMMAND.COM) consists of eight characters followed by three characters. 
In this
case, the value returned by GetVolumeInformation would be 8.3. If the 
operating
system supports long file names, the value returned will be 255, 
regardless of
the actual length of the file name.

Example Program
This program shows how you can retrieve the volume name of a disk, and 
how to
determine whether the operating system supports long file names.

 1. Create a new project in Visual Basic. Form1 is created by default.
 2. Add the following Declare statement to the General Declarations 
section of
    Form1 (note that this Declare statement must be typed as a single 
line of
    text):

Private Declare Function GetVolumeInformation Lib "kernel32" Alias
   "GetVolumeInformationA" (ByVal lpRootPathName As String, ByVal
   lpVolumeNameBuffer As String, ByVal nVolumeNameSize As Long,
   lpVolumeSerialNumber As Long, lpMaximumComponentLength As Long,
   lpFileSystemFlags As Long, ByVal lpFileSystemNameBuffer As String,
   ByVal nFileSystemNameSize As Long) As Long

 3. Add a Text Box control to Form1. Text1 is created by default.
 4. Add a second Text Box control to Form1. Text2 is created by 
default.
 5. Add a Command Button control to Form1. Command1 is created by 
default.
 6. Add the following code to the Click event for Command1.

Private Sub Command1_Click()
    Dim nRet As Long
    Dim VolName As String
    Dim VolSN As Long
    Dim MaxCompLen As Long
    Dim VolFlags As Long
    Dim VolFileSys As String
    VolName = Space$(256)
    VolFileSys = Space$(256)
    nRet = GetVolumeInformation("C:\", VolName, Len(VolName), VolSN,
       MaxCompLen, VolFlags, VolFileSys, Len(VolFileSys))
    text1.Text = VolName
    If MaxCompLen = 255 Then
        Text2.Text = "Long file names are supported"
    Else
        Text2.Text = "Long file names are NOT supported"
    End If
End Sub

Run the example program by pressing F5. Click the command button. The 
disk's
volume name is displayed in the first text box. A message is displayed 
in the
second text box if long file names are supported.

Additional References
"GetVolumeInformation." (Development Library, Product Documentation, 
SDKs,
   Win32 SDK, Win32 Programmer's Reference, Functions)
"The Disk Information Viewer Sample Application." (Development Library, 
Books
   and Periodicals, Advanced Windows NT, Chapter Nine File Systems And 
File I/O,
   System and Volume Operations)