Platform SDK: Files and I/O

GetVolumeInformation

The GetVolumeInformation function retrieves information about a file system and volume whose root directory is specified.

BOOL GetVolumeInformation(
  LPCTSTR lpRootPathName,           // root directory
  LPTSTR lpVolumeNameBuffer,        // volume name buffer
  DWORD nVolumeNameSize,            // length of name buffer
  LPDWORD lpVolumeSerialNumber,     // volume serial number
  LPDWORD lpMaximumComponentLength, // maximum file name length
  LPDWORD lpFileSystemFlags,        // file system options
  LPTSTR lpFileSystemNameBuffer,    // file system name buffer
  DWORD nFileSystemNameSize         // length of file system name buffer
);

Parameters

lpRootPathName

[in] Pointer to a string that contains the root directory of the volume to be described. If this parameter is NULL, the root of the current directory is used. A trailing backslash is required. For example, you would specify \\MyServer\MyShare as \\MyServer\MyShare\, or the C drive as "C:\".

lpVolumeNameBuffer

[out] Pointer to a buffer that receives the name of the specified volume.

nVolumeNameSize

[in] Specifies the length, in TCHARs, of the volume name buffer. This parameter is ignored if the volume name buffer is not supplied.

lpVolumeSerialNumber

[out] Pointer to a variable that receives the volume serial number. This parameter can be NULL if the serial number is not required.

Windows 95/98: If the queried volume is a network drive, the serial number will not be returned.

lpMaximumComponentLength

[out] Pointer to a variable that receives the maximum length, in TCHARs, of a file name component supported by the specified file system. A file name component is that portion of a file name between backslashes.

The value stored in variable pointed to by *lpMaximumComponentLength is used to indicate that long names are supported by the specified file system. For example, for a FAT file system supporting long names, the function stores the value 255, rather than the previous 8.3 indicator. Long names can also be supported on systems that use the NTFS file system.

lpFileSystemFlags

[out] Pointer to a variable that receives flags associated with the specified file system. This parameter can be any combination of the following flags; however, FS_FILE_COMPRESSION and FS_VOL_IS_COMPRESSED are mutually exclusive.

Value	Meaning
FS_CASE_IS_PRESERVED	The file system preserves the case of file names when it places a name on disk.
FS_CASE_SENSITIVE	The file system supports 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 ACLs. For example, NTFS preserves and enforces ACLs, and FAT does not.
FS_FILE_COMPRESSION	The file system supports file-based compression.
FS_VOL_IS_COMPRESSED	The specified volume is a compressed volume; for example, a DoubleSpace volume.
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

[out] Pointer to a buffer that receives the name of the file system (such as FAT or NTFS).

nFileSystemNameSize

[in] Specifies the length, in TCHARs, of the file system name buffer. This parameter is ignored if the file system name buffer is not supplied.

Return Values

If all the requested information is retrieved, the return value is nonzero.

If not all the requested information is retrieved, the return value is zero. To get extended error information, call GetLastError.

Remarks

If you are attempting to obtain information about a floppy drive that does not have a floppy disk or a CD-ROM drive that does not have a compact disc, the system displays a message box asking the user to insert a floppy disk or a compact disc, respectively. To prevent the system from displaying this message box, call the SetErrorMode function with SEM_FAILCRITICALERRORS.

The FS_VOL_IS_COMPRESSED flag is the only indicator of volume-based compression. The file system name is not altered to indicate compression. This flag comes back set on a DoubleSpace volume, for example. With volume-based compression, an entire volume is either compressed or not compressed.

The FS_FILE_COMPRESSION flag indicates whether a file system supports file-based compression. With file-based compression, individual files can be compressed or not compressed.

The FS_FILE_COMPRESSION and FS_VOL_IS_COMPRESSED flags are mutually exclusive; both bits cannot come back set.

The maximum component length value, stored in lpMaximumComponentLength, is the only indicator that a volume supports longer-than-normal FAT (or other file system) file names. The file system name is not altered to indicate support for long file names.

The GetCompressedFileSize function obtains the compressed size of a file. The GetFileAttributes function can determine whether an individual file is compressed.

Requirements

  Windows NT/2000: Requires Windows NT 3.1 or later.
  Windows 95/98: Requires Windows 95 or later.
  Header: Declared in Winbase.h; include Windows.h.
  Library: Use Kernel32.lib.
  Unicode: Implemented as Unicode and ANSI versions on Windows NT/2000.

GetVolumeInformation

Parameters

Return Values

Remarks

Requirements

See Also