PRODUCT  :  Borland C++                           NUMBER  :  1731
  VERSION  :  All
       OS  :  WIN
     DATE  :  October 25, 1993                         PAGE  :  1/4

    TITLE  :  Getting a drive's serial number under Windows




  #define STRICT
  //
  // winseria.c - Getting the drive Serial Number under Window.
  //
  /*

    This file shows an example of calling a real mode interrupt
    ( 0x21, 0x69 ) from within a Windows application to determine
    the Serial Number, Volume Label, and File System Type ( which
    is either "FAT12" or "FAT16". The Info Level will be 0.

    One of the main issues involved is to create two pointers to
    the same memory location - a selector address which is
    usable by Windows, and a segment address which is usable by
    DOS. This is done using the GlobalDOSAlloc() function, which
    returns both the selector and the segment address of the
    allocated memory. Note that this function should not be used
    for most allocation because it allocates a non-moveable
    memory block from the base 1Meg of memory.

    The segment address is then passed to DOS int 21h, 69h to get
    information regarding the drive. The selector address is then
    used by the Windows parts of the code to access that data.

  */

  #include <dos.h>      // MK_FP
  #include <stdlib.h>   // ltoa()
  #include <string.h>   // strncpy(), strcpy(), strup()
  #include <windows.h>  // wsprintf()

  // Structure to contain the register values for the
  //    DPMI services
  typedef struct
  {
    DWORD di,si,bp,res1,bx,dx,cx,ax;
    WORD flags, es,ds,fs,gs,res2,res3,sp,ss;
  } DPMIRegs;

  // Stucture to contain the disk information
  typedef struct {
    unsigned int InfoLevel;
    unsigned long Serial;













  PRODUCT  :  Borland C++                           NUMBER  :  1731
  VERSION  :  All
       OS  :  WIN
     DATE  :  October 25, 1993                         PAGE  :  2/4

    TITLE  :  Getting a drive's serial number under Windows




    unsigned char VolumeLabel[11];
    unsigned char FileSystemType[8];
  } Info;

  // Create globally to initialize to Zero
  DPMIRegs r;

  // Use DPMI services to access Real mode
  void SimRealInt (BYTE i, DPMIRegs far *p)
  {
    asm {
      mov bl, [i]    // DOS interupt
      mov bh, 0
      les di, [p]    // Register Values
      mov cx, 0
      mov ax, 0300h
      int 31h
    }
  }

  #pragma argsused
  int PASCAL WinMain( HINSTANCE hInstance, HINSTANCE
                      hPrevInstance, LPSTR lpCmdLine, int
                      nCmdShow )
  {
     int       Drive=3 ;      // 3 = C drive
     DWORD     dwValue ;
     unsigned  size ;
     char      temp[5] ;
     char      diskInfo[120] ;
     char      Label[12] ;
     char      Type[9] ;
     char      Serial[10] ;

     WORD      wSegment, wSelector ;
     Info far  *WindowsPtr ;

     size = sizeof( Info ) ;

     dwValue = GlobalDosAlloc( size ) ;
     if (!dwValue)
     {
       MessageBox( NULL, "Could not Allocate Memory", "Error",













  PRODUCT  :  Borland C++                           NUMBER  :  1731
  VERSION  :  All
       OS  :  WIN
     DATE  :  October 25, 1993                         PAGE  :  3/4

    TITLE  :  Getting a drive's serial number under Windows




                   MB_ICONINFORMATION | MB_OK ) ;
       return 1 ;
     }

     wSegment   = HIWORD(dwValue) ;
     wSelector  = LOWORD(dwValue) ;
     WindowsPtr = (Info far *)MK_FP(wSelector,0) ;

     r.ax = 0x6900;
     r.bx = Drive ;
     r.dx = 0;
     r.ds  = wSegment;
     SimRealInt (0x21, &r) ; // Call DOS int 21h, 69h

     // Check for read error
     if ( r.flags & 0x01)
     {
        WindowsPtr->Serial = 0;
     }

     // Add a NULL terminator to the strings which were returned
     //    in the Info structure.
     _fstrncpy( Label, (char far *)WindowsPtr->VolumeLabel, 11 ) ;
     Label[11] = 0 ;
     _fstrncpy( Type, (char far *)WindowsPtr->FileSystemType, 8 );
     Type[8] = 0 ;
     ltoa( WindowsPtr->Serial, Serial, 16 ) ;
     _fstrcpy( temp, &Serial[4] ) ;
     _fstrcpy( &Serial[5], temp ) ;
     _fstrupr( Serial ) ; // Convert all characters to UPPER CASE
     Serial[4] = ':' ;
     Serial[9] = 0 ;
     // Format the string to be displayed.
     wsprintf( diskInfo, "Drive:\t\t%c\r\n"
                    "Serial Number:\t%s\r\n"
                    "Volume Label:\t%s\r\n"
                    "File System type:\t%s",
                    (Drive + 64), (char far*)Serial,
                    (char far *)Label, (char far *)Type ) ;

     MessageBox( NULL, (char far *)diskInfo, "Disk Info",
                 MB_ICONINFORMATION | MB_OK ) ;














  PRODUCT  :  Borland C++                           NUMBER  :  1731
  VERSION  :  All
       OS  :  WIN
     DATE  :  October 25, 1993                         PAGE  :  4/4

    TITLE  :  Getting a drive's serial number under Windows




     GlobalDosFree(wSelector) ;

     return 0 ;
  }

  DISCLAIMER: You have the right to use this technical information
  subject to the terms of the No-Nonsense License Statement that
  you received with the Borland product to which this information
  pertains.