KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q193623: HOWTO: Determine the Logical Drives on a System

Article: Q193623
Product(s): Microsoft FoxPro
Version(s): WINDOWS:6.0
Operating System(s): 
Keyword(s): 
Last Modified: 03-AUG-1999

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft Visual FoxPro for Windows, version 6.0 
-------------------------------------------------------------------------------

SUMMARY
=======

You can use the GetLogicalDrives() API function to find which logical drives are
present in a system. The GetLogicalDrives() function returns a 32-bit value in
which each bit represents whether the logical drive exists. For example, if the
system has an A drive, bit 0 will be set, and if the system has a drive Z, bit
25 will be set.

MORE INFORMATION
================

The following program demonstrates the use of the GetLogicalDrives() API
function. The sample program calls the function and loops through each bit of
the return value, using the FoxPro Bittest() function to determine if a
particular drive is present or not. It displays all the drives on the system and
their drive types in a message box.

Sample Code
-----------

     * This program enumerates all drives on a Win32 system and
     * displays a message box containing the drive letters and
     * types of all logical drives on the system.
     *

     * Constants for drive types.
     #DEFINE DRIVE_UNKNOWN 0
     #DEFINE DRIVE_NO_ROOT_DIR 1
     #DEFINE DRIVE_REMOVABLE 2
     #DEFINE DRIVE_FIXED 3
     #DEFINE DRIVE_REMOTE 4
     #DEFINE DRIVE_CDROM 5
     #DEFINE DRIVE_RAMDISK 6
     #DEFINE CR CHR(13)

     DECLARE INTEGER GetLogicalDrives IN Win32API
     DECLARE INTEGER GetDriveType IN Win32API STRING RootPath

     PRIVATE lcDrivestring, lcDriveRoot, liDrivelist, lcDrives, i
     lcDrives = ""

     * GetLogicalDrives returns a 32-bit value containing a list of
     * available drives. If the specific bit is ON, the drive letter
     * corresponding to that position exists.
     liDrivelist = GetLogicalDrives()

     * Check each of the bits
     FOR i = 0 TO 31
        IF BITTEST(liDrivelist, i)
     * If the 0th bit is ON, that means drive 'A:',
     * the 2nd bit is 'C:", etc.
           lcDriveRoot = CHR(65 + i) + ":\"
     * Perform a GetDriveType to determine if it is a floppy, CD, etc.
           lcDrivetype = GetDriveType(lcDriveRoot)
           DO CASE
              CASE lcDrivetype = DRIVE_UNKNOWN
                 lcDrivestring = "Cannot be determined"
              CASE lcDrivetype = DRIVE_NO_ROOT_DIR
                 lcDrivestring = "Root directory does not exist"
              CASE lcDrivetype = DRIVE_REMOVABLE
                 lcDrivestring = "Floppy/removable drive"
              CASE lcDrivetype = DRIVE_FIXED
                 lcDrivestring = "Hard drive/nonremovable drive"
              CASE lcDrivetype = DRIVE_REMOTE
                 lcDrivestring = "Remote/Network drive"
              CASE lcDrivetype = DRIVE_CDROM
                 lcDrivestring = "CD-ROM drive"
              CASE lcDrivetype = DRIVE_RAMDISK
                 lcDrivestring = "RAM disk"
           ENDCASE
           lcDrives = lcDrives + lcDriveRoot + " " + lcDrivestring + CR
        ENDIF
     NEXT

     =MESSAGEBOX(lcDrives, ;
        0 + 64 + 0)

REFERENCES
==========

"Advanced Windows", Third Edition, Jeffrey Richter, pages 615-695, Microsoft
Press, 1997.

Additional query words: kbVFp600 kbAPI

======================================================================
Keywords          :  
Technology        : kbVFPsearch kbAudDeveloper kbVFP600
Version           : WINDOWS:6.0
Issue type        : kbhowto

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.