From: neridan@central.co.nz (Neil Daniell)

Setting / Unsetting NumLock Status in OS/2 App

[1] Required variables:

        HFILE                hfile;              // File handle for device
        ULONG                ulAction;
        ULONG                ulLength;
        BYTE                 KeyState[257];
        SHIFTSTATE           strShiftState;
        unsigned short       usLightState;


[2] Open keyboard device for use with DosDevIOCtl:
        DosOpen (
                "KBD$",
                &hfile,
                &ulAction,
                0L,
                0,
                FILE_OPEN,
                OPEN_ACCESS_READONLY | OPEN_SHARE_DENYNONE,
                0 );

[3] Obtain Shift Status information
        using DosDevIOCtl         Category IOCTL_KEYBBOARD        ( 0x0004 )
                                Function KBD_GETSHIFTSTATE        ( 0x0073 )

        ulAction = 0;
        ulLength = sizeof ( strShiftState );

        DosDevIOCtl (
                hfile,
                IOCTL_KEYBOARD,
                KBD_GETSHIFTSTATE,
                0,
                0,
                &ulAction,
                &strShiftState,
                sizeof( strShiftState ),
                &ulLength );

[4] Get Keyboard state table:

        WinSetKeyboardStateTable (
                HWND_DEKSTOP,
                &KeyState[1],
                FALSE );

[5] Set shift and key state:

If setting key ON:
        KeyState[VK_NUMLOCK+1] |= 0x01;
        strShiftState.fsState |= NUMLOCK_ON;

If setting key OFF:
        KeyState[VK_NUMLOCK+1] &= ~0x01;
        strShiftState.fsState &= ~NUMLOCK_ON;

[6] Update keyboard state table:

        WinSetKeyboardStateTable (
                HWND_DEKSTOP,
                &KeyState[1],
                TRUE );

[7] Update shift state:
        using DosDevIOCtl         Category IOCTL_KEYBBOARD        ( 0x0004 )
                                Function KBD_SETSHIFTSTATE        ( 0x0053 )

        ulAction = sizeof ( strShiftState );
        ulLength = 0;

        DosDevIOCtl (
                hfile,
                IOCTL_KEYBOARD,
                KBD_SETSHIFTSTATE,
                &strShiftState,
                sizeof( strShiftState ),
                &ulAction,
                0,
                0,
                &ulLength );

[8] Set LED status
        using DosDevIOCtl
                Category IOCTL_KEYBBOARD        ( 0x0004 )
           Function KBD_ALTERKEYBOARDLED        ( 0x005A )
                        NB: This constant is NOT predefined,
                            will require specific declaration.

        usLightState = ( strShifState.fsState & ( CAPSLOCK_ON | NUMLOCK_ON |
SCROLLLOCK_ON ) ) >> 4;
        ulAction = sizeof ( usLightState );

        DosDevIOCtl (
                hfile,
                IOCTL_KEYBOARD,
                KBD_ALTERKEYBOARDLED,
                &usLightState,
                sizeof( usLightState ),
                &ulAction,
                0,
                0,
                &ulLength );


[9] Close device:

                DosClose ( hfile );