PRODUCT  :  Borland C++                            NUMBER  :  724
  VERSION  :  2.0
       OS  :  DOS
     DATE  :  October 19, 1993                         PAGE  :  1/4

    TITLE  :  Example Mouse Event Handler




  /**************************************************************
    An example of using a mouse event handler.
  **************************************************************/
  #include <stdio.h>
  #include <conio.h>
  #include <dos.h>

  #define  MOUSEINT  geninterrupt( 0x33 )

  /*-- mouse event masks (use with M_event) --*/
  #define  MOUSEMOVE      0x01        /* Use, for example:     */
  #define  L_PRESS        0x02       /* L_PRESS | MOUSEMOVE  */
  #define  L_RELEASE      0x04
  #define  R_PRESS        0x08
  #define  R_RELEASE      0x10

  /*-- mouse button status macros --*/
  #define  L_DOWN         ( M_buttonstatus & 0x01 )
  #define  R_DOWN         ( M_buttonstatus & 0x02 )

  #define  HANDLER_EXIT_PROCESSING()  \
   __emit__( (unsigned char) 0x5D,  \
             (unsigned char) 0x5F,  \
             (unsigned char) 0x5E,  \
             (unsigned char) 0x1F,  \
             (unsigned char) 0x07,  \
             (unsigned char) 0x5A,  \
             (unsigned char) 0x59,  \
             (unsigned char) 0x5B,  \
             (unsigned char) 0x58,  \
             (unsigned char) 0xCB  ) ;
  #if 0
  -------------------------------------------
  The above emitted code is equivalent to the
  following assembler code (but does not
  require the -B compiling option):
         asm  pop   bp    ;
         asm  pop   di    ;
         asm  pop   si    ;
         asm  pop   ds    ;
         asm  pop   es    ;     /* interrupt exit processing */
         asm  pop   dx    ;
         asm  pop   cx    ;













  PRODUCT  :  Borland C++                            NUMBER  :  724
  VERSION  :  2.0
       OS  :  DOS
     DATE  :  October 19, 1993                         PAGE  :  2/4

    TITLE  :  Example Mouse Event Handler




         asm  pop   bx    ;
         asm  pop   ax    ;
         asm  retf        ;     /* far return */
  --------------------------------------------
  #endif

  /*--Global mouse status variables --*/
  int  M_xpos, M_ypos,         /* cursor location */
       M_buttonstatus,         /* bits 0-2 ON if button is down */
       M_eventcount,           /* # of times event has occurred */
       M_event ;               /* flags a mouse event */

  /*-- Reset mouse -- returns # of buttons or 0 if problems --*/
  int Mreset( void )
  {
   _AX = 0 ;
   MOUSEINT ;
   return( _AX  ?  _BX  : _AX ) ;
  }

  /*-- Show mouse cursor --*/
  void Mshow( void )
  {
   _AX = 1 ;
   MOUSEINT ;
  }

  /*-- Hide mouse cursor --*/
  void Mhide( void )
  {
   _AX = 2 ;
   MOUSEINT ;
  }

  /*-- Get mouse position and button status --*/
  void Mpos( void )
  {
   _AX = 3 ;
   MOUSEINT ;
   M_xpos = _CX ;
   M_ypos = _DX ;
   M_buttonstatus = _BX ;
  }













  PRODUCT  :  Borland C++                            NUMBER  :  724
  VERSION  :  2.0
       OS  :  DOS
     DATE  :  October 19, 1993                         PAGE  :  3/4

    TITLE  :  Example Mouse Event Handler




  /*-- Installs mouse handler --*/
  void Minsthandler( unsigned mask, void interrupt (*fn)(void) )
  {
   union REGS   reg ;
   struct SREGS seg ;
   reg.x.ax = 20 ;      /* mouse fn. 20 -- replaces fn.12 */
   reg.x.cx = mask ;
   reg.x.dx = FP_OFF( fn ) ;
   seg.es = FP_SEG( fn ) ;
   int86x( 0x33, &reg, &reg, &seg ) ;
  }

  /*---------------------------------------------------------
   This mouse event handler simply updates mouse information.
  ----------------------------------------------------------*/
  void interrupt mousehandler( void )
  {
   M_event = _AX ;
   M_buttonstatus = _BX ;
   M_xpos = _CX ;
   M_ypos = _DX ;
   HANDLER_EXIT_PROCESSING() ;
  }

  /*----------------------------------------------------
   Demonstrate mouse tracking via mouse event handler.
  ----------------------------------------------------*/
  main()
  {
   clrscr() ;
   if( !Mreset() ) {
      fputs("Cannot initialize mouse.", stderr) ;
      exit(1) ;
   }

   Minsthandler( MOUSEMOVE, mousehandler ) ;
   M_event = 0 ;
   Mshow() ;

   gotoxy(20,24) ;
   cprintf("Text mode mouse tracking with event handler") ;
   gotoxy(20,25) ;
   cprintf("        Press any KEY to quit.") ;













  PRODUCT  :  Borland C++                            NUMBER  :  724
  VERSION  :  2.0
       OS  :  DOS
     DATE  :  October 19, 1993                         PAGE  :  4/4

    TITLE  :  Example Mouse Event Handler




   gotoxy( 1, 1) ;
   cprintf("Position and button status is updated only when the
            mouse moves.") ;
   gotoxy( 1, 4);
   cprintf("Button Status at time of handler call:") ;

   while( !kbhit() ) {
      if( M_event ) {
         gotoxy(1,2) ;
         cprintf("Cursor position: %3d, %3d", M_xpos/8+1,
                  M_ypos/8+1 ) ;
         gotoxy(1,5) ;
         L_DOWN ? cprintf("Left  DOWN") : cprintf("Left  UP  ") ;
         gotoxy(20,5) ;
         R_DOWN ? cprintf("Right DOWN") : cprintf("Right UP  ") ;
         M_event = 0 ;      /* reset the event */
      }
   }
   Mhide() ;
   Mreset() ;
  }

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  subject to the terms of the No-Nonsense License Statement that
  you received with the Borland product to which this information
  pertains.