PRODUCT  :  Borland C++                           NUMBER  :  1291
  VERSION  :  All
       OS  :  DOS
     DATE  :  October 25, 1993                         PAGE  :  1/2

    TITLE  :  How to monitor the keyboard for multiple key presses.




  // This is a short demonstration of monitoring the keyboard
  // to determine what key or key combination is pressed at
  // any given time.

  #include <dos.h>
  #include <conio.h>

  #define TRUE 1
  #define FALSE 0

  // keyBoardOldHandler keeps track of old interrupt function
  void interrupt (*keyboardOldHandler)(...);

  // keyboardISR will be our new keyboard interrupt service
  // routine
  void interrupt keyboardISR(...);

  int keyPressed[128];  // Array specifying for each key
                        // whether it's up or down

  char haveKey=FALSE;   // a flag to tell us if a new
                        // keyboard event happened

  void keyboardCapture()
  {
      keyboardOldHandler=getvect(9);
      setvect(9,keyboardISR);
  }

  void keyboardRelease()
  {
      setvect(9,keyboardOldHandler);
  }

  void interrupt keyboardISR(...)
  {
      int i,j;

      i=inportb(0x60);          // read in scan code
      j=inportb(0x61);          // read in command status
      outportb(0x61,j|0x80);    // reset the keyboard controller
      outportb(0x61,j);
      // if bit 7 (high bit) is set, the key was released













  PRODUCT  :  Borland C++                           NUMBER  :  1291
  VERSION  :  All
       OS  :  DOS
     DATE  :  October 25, 1993                         PAGE  :  2/2

    TITLE  :  How to monitor the keyboard for multiple key presses.




      if(i&0x80) keyPressed[i&0x7f]=0;
      // if bit 7 (high bit) is 0, the key just went down
      else keyPressed[i&0x7f]=1;
      outportb(0x20,0x20);
      haveKey=TRUE;
  }

  void main()
  {
      int i,done=FALSE;

      // hook interrupt 9
      keyboardCapture();
      while(!done)
      {
          if (haveKey) // haveKey is set by the ISR to tell us
                       // that the keyboard did something
          {
              haveKey=FALSE;
              gotoxy(1,1);
              clreol();
              for (i=0; i<128; i++)  // scan status of every key
              {
                  if (keyPressed[i]) cprintf("%d ",i);
              }
              // check to see if ESC was pressed  (if so, exit)
              if(keyPressed[1]) done=TRUE;
          }
      }
      gotoxy(1,2);
      // release interrupt 9
      keyboardRelease();
  }

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