Expert: Joseph Moore - 7/27/2009

Question
please help with the program that will help to on caps lock, num lock and scroll lock.please!!

Answer
If this is a Windows machine, then the following will work (this particular example is num lock, but the code will work for others, too, just with different key codes).  Also, please note: this particular program is really rather annoying... it loops infinitely, toggling num lock on and off repeatedly... :)

#include <Windows.h>

BOOL SetNumLock( BOOL bState )
{
   BYTE keyState[256];

   GetKeyboardState((LPBYTE)&keyState);
   if( (bState && !(keyState[VK_NUMLOCK] & 1)) ||
       (!bState && (keyState[VK_NUMLOCK] & 1)) )
   {
       // Simulate a key press
       keybd_event( VK_NUMLOCK,
           0x45,
           KEYEVENTF_EXTENDEDKEY | 0,
           0 );

       // Simulate a key release
       keybd_event( VK_NUMLOCK,
           0x45,
           KEYEVENTF_EXTENDEDKEY | KEYEVENTF_KEYUP,
           0);
   }

   return (keyState[VK_NUMLOCK]);
}

void main()
{
   BOOL set = TRUE;
   while(1)
       set = !SetNumLock(set);
}