Windows API Guide - Reference - Volume 1: Version 3.0 For the MS-DOS and PC-DOS Operating Systems

2017-07-07 02:10:07

Declare Function GetVolumeInformation Lib "kernel32.dll" 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

Platforms

Windows 95: Supported.
Windows 98: Supported.
Windows NT: Requires Windows NT 3.1 or later.
Windows 2000: Supported.
Windows CE: Not Supported.

Description & Usage

GetVolumeInformation retrieves information describing a disk volume and the file system it uses. This information includes things such as the volume label and the disk's serial number.

Return Value

If an error occured, the function returns 0 (use GetLastError to get the error code). If successful, the function returns a non-zero value.

Visual Basic-Specific Issues

None.

Parameters

lpRootPathName

The root directory of the disk volume to be described. This directory must include a trailing backslash character. For example, to describe the C: drive, this would be "C:\".

lpVolumeNameBuffer

Receives the null-terminated volume label of the volume. This string must be large enough to receive the text.

nVolumeNameSize

The length of the string passed as lpVolumeNameBuffer.

lpVolumeSerialNumber

Receives the serial number of the volume. When displayed, this value should be shown in hexadecimal with a dash before the last four hex digits. Windows 95/98: If the volume is a netword drive, the serial number will not be retrieved.

lpMaximumComponentLength

Receives the maximum length of a file name component supported by the file system. A file name component is any portion of a file name between backslashes. This value is used primarily to determine if the volume supports long file names or if it is limited to the old 8.3 system.

lpFileSystemFlags

A combination of the following flags describing other features of the file system used by the volume:

FS_CASE_IS_PRESERVED: The file system preserves the case of file names.
FS_CASE_SENSITIVE: The file system uses case-sensitive file names.
FS_UNICODE_STORED_ON_DISK: The file system supports Unicode in file names as they appear on disk.
FS_PERSISTENT_ACLS: The file system preserves and enforces access control lists (ACLs).
FS_FILE_COMPRESSION: The file system supports file-based compression, where individual files can be compressed while others are not.
FS_VOL_IS_COMPRESSED: The entire volume is compressed; for example, DoubleSpace has been used on the disk.
FILE_NAMED_STREAMS: The file system supports named streams.
FILE_SUPPORTS_ENCRYPTION: The file system supports the Encrypted File System (EFS).
FILE_SUPPORTS_OBJECT_IDS: The file system supports object identifiers.
FILE_SUPPORTS_REPARSE_POINTS: The file system supports reparse points.
FILE_SUPPORTS_SPARSE_FILES: The file system supports sparse files.
FILE_VOLUME_QUOTAS: The file system supports disk quotas.

lpFileSystemNameBuffer

Receives the null-terminated name of the file system. This string must be long enough to receive the text.

nFileSystemNameSize

The length of the string passed as lpFileSystemNameBuffer.

Constant Definitions

Const FS_CASE_IS_PRESERVED = &H2 Const FS_CASE_SENSITIVE = &H1 Const FS_UNICODE_STORED_ON_DISK = &H4 Const FS_PERSISTENT_ACLS = &H8 Const FS_FILE_COMPRESSION = &H10 Const FS_VOLUME_IS_COMPRESSED = &H8000 Const FILE_NAMED_STREAMS = &H40000 Const FILE_SUPPORTS_ENCRYPTION = &H20000 Const FILE_SUPPORTS_OBJECT_IDS = &H10000 Const FILE_SUPPORTS_REPARSE_POINTS = &H80 Const FILE_SUPPORTS_SPARSE_FILES = &H40 Const FILE_VOLUME_QUOTAS = &H20

Example

' This code is licensed according to the terms and conditions listed here. ' Declarations and such needed for the example: ' (Copy them to the (declarations) section of a module.) Public Declare Function GetVolumeInformation Lib "kernel32.dll" 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 ' Display the volume label, serial number, and file system name ' of the C: drive. Note how the serial number value is manipulated to ' display it properly. Dim volname As String ' receives volume name of C: Dim sn As Long ' receives serial number of C: Dim snstr As String ' display form of serial number Dim maxcomplen As Long ' receives maximum component length Dim sysflags As Long ' receives file system flags Dim sysname As String ' receives the file system name Dim retval As Long ' return value ' Initialize string buffers. volname = Space(256) sysname = Space(256) ' Get information about the C: drive's volume. retval = GetVolumeInformation("C:\", volname, Len(volname), sn, maxcomplen, _ sysflags, sysname, Len(sysname)) ' Remove the trailing nulls from the two strings. volname = Left(volname, InStr(volname, vbNullChar) - 1) sysname = Left(sysname, InStr(sysname, vbNullChar) - 1) ' Format the serial number properly. snstr = Trim(Hex(sn)) snstr = String(8 - Len(snstr), "0") & snstr snstr = Left(snstr, 4) & "-" & Right(snstr, 4) ' Display the volume name, serial number, and file system name. Debug.Print "Volume Name: "; volname Debug.Print "Serial Number: "; snstr Debug.Print "File System: "; sysname