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Using Raw Input

This section includes sample code for the following purposes:

Registering for Raw Input

Example 1

In this sample, an application specifies the raw input from game controllers (both game pads and joysticks) and all devices off the telephony usage page except answering machines.

RAWINPUTDEVICE Rid[4];
        
Rid[0].usUsagePage = 0x01;          // HID_USAGE_PAGE_GENERIC
Rid[0].usUsage = 0x05;              // HID_USAGE_GENERIC_GAMEPAD
Rid[0].dwFlags = 0;                 // adds game pad
Rid[0].hwndTarget = 0;

Rid[1].usUsagePage = 0x01;          // HID_USAGE_PAGE_GENERIC
Rid[1].usUsage = 0x04;              // HID_USAGE_GENERIC_JOYSTICK
Rid[1].dwFlags = 0;                 // adds joystick
Rid[1].hwndTarget = 0;

Rid[2].usUsagePage = 0x0B;          // HID_USAGE_PAGE_TELEPHONY
Rid[2].usUsage = 0x00; 
Rid[2].dwFlags = RIDEV_PAGEONLY;    // adds all devices from telephony page
Rid[2].hwndTarget = 0;

Rid[3].usUsagePage = 0x0B;          // HID_USAGE_PAGE_TELEPHONY
Rid[3].usUsage = 0x02;              // HID_USAGE_TELEPHONY_ANSWERING_MACHINE
Rid[3].dwFlags = RIDEV_EXCLUDE;     // excludes answering machines
Rid[3].hwndTarget = 0;

if (RegisterRawInputDevices(Rid, 4, sizeof(Rid[0])) == FALSE)
{
    //registration failed. Call GetLastError for the cause of the error.
}

Example 2

In this sample, an application wants raw input from the keyboard and mouse but wants to ignore legacy keyboard and mouse window messages (which would come from the same keyboard and mouse).

RAWINPUTDEVICE Rid[2];
        
Rid[0].usUsagePage = 0x01;          // HID_USAGE_PAGE_GENERIC
Rid[0].usUsage = 0x02;              // HID_USAGE_GENERIC_MOUSE
Rid[0].dwFlags = RIDEV_NOLEGACY;    // adds mouse and also ignores legacy mouse messages
Rid[0].hwndTarget = 0;

Rid[1].usUsagePage = 0x01;          // HID_USAGE_PAGE_GENERIC
Rid[1].usUsage = 0x06;              // HID_USAGE_GENERIC_KEYBOARD
Rid[1].dwFlags = RIDEV_NOLEGACY;    // adds keyboard and also ignores legacy keyboard messages
Rid[1].hwndTarget = 0;

if (RegisterRawInputDevices(Rid, 2, sizeof(Rid[0])) == FALSE)
{
    //registration failed. Call GetLastError for the cause of the error
}

Performing a Standard Read of Raw Input

This sample shows the minimal pattern for standard reading raw input from a WM_INPUT message handler. Each WM_INPUT message carries an HRAWINPUT handle in lParam referencing the current input event — it must be read via GetRawInputData before calling DefWindowProc.

For high-frequency devices such as mice at 1000Hz, multiple events may accumulate between message loop iterations. In that case, follow up with GetRawInputBuffer to drain the remaining queue — see the optional Phase 2 below.

/* Initialized once at startup */
UINT  g_bufferSize = 64 * sizeof(RAWINPUT);
void* g_pBuffer    = NULL;

/* Call once before entering the message loop: */
/* g_pBuffer = malloc(g_bufferSize); */

void ProcessInput(const RAWINPUT* input)
{
    if (input->header.dwType == RIM_TYPEKEYBOARD)
    {
        const RAWKEYBOARD* kb = &input->data.keyboard;
        const char* transition = (kb->Flags & RI_KEY_BREAK) ? "up" : "down";
        const char* extended   = (kb->Flags & RI_KEY_E0)    ? " e0" :
                                 (kb->Flags & RI_KEY_E1)    ? " e1" : "";
        printf("keyboard: vk=0x%02x scan=0x%02x %s%s msg=0x%04x extra=0x%08x\n",
            kb->VKey, kb->MakeCode, transition, extended,
            kb->Message, kb->ExtraInformation);
    }
    else if (input->header.dwType == RIM_TYPEMOUSE)
    {
        const RAWMOUSE* mouse = &input->data.mouse;
        const char* moveMode  = (mouse->usFlags & MOUSE_MOVE_ABSOLUTE) ? "abs" : "rel";

        printf("mouse: move %s dx=%d dy=%d\n", moveMode, mouse->lLastX, mouse->lLastY);

        if (mouse->usButtonFlags & RI_MOUSE_LEFT_BUTTON_DOWN)   printf("  left down\n");
        if (mouse->usButtonFlags & RI_MOUSE_LEFT_BUTTON_UP)     printf("  left up\n");
        if (mouse->usButtonFlags & RI_MOUSE_RIGHT_BUTTON_DOWN)  printf("  right down\n");
        if (mouse->usButtonFlags & RI_MOUSE_RIGHT_BUTTON_UP)    printf("  right up\n");
        if (mouse->usButtonFlags & RI_MOUSE_MIDDLE_BUTTON_DOWN) printf("  middle down\n");
        if (mouse->usButtonFlags & RI_MOUSE_MIDDLE_BUTTON_UP)   printf("  middle up\n");
        if (mouse->usButtonFlags & RI_MOUSE_BUTTON_4_DOWN)      printf("  x1 down\n");
        if (mouse->usButtonFlags & RI_MOUSE_BUTTON_4_UP)        printf("  x1 up\n");
        if (mouse->usButtonFlags & RI_MOUSE_BUTTON_5_DOWN)      printf("  x2 down\n");
        if (mouse->usButtonFlags & RI_MOUSE_BUTTON_5_UP)        printf("  x2 up\n");

        if (mouse->usButtonFlags & RI_MOUSE_WHEEL)
            printf("  wheel delta=%d\n",  (int)(short)mouse->usButtonData);
        if (mouse->usButtonFlags & RI_MOUSE_HWHEEL)
            printf("  hwheel delta=%d\n", (int)(short)mouse->usButtonData);
    }
    else if (input->header.dwType == RIM_TYPEHID)
    {
        const RAWHID* hid = &input->data.hid;
        printf("hid: count=%u size=%u\n", hid->dwCount, hid->dwSizeHid);
    }
}

void DrainRawInputQueue(void)
{
    for (;;)
    {
        UINT bufferSize = g_bufferSize;
        UINT count = GetRawInputBuffer((RAWINPUT*)g_pBuffer, &bufferSize, sizeof(RAWINPUTHEADER));

        if (count == 0)
            break;

        if (count == (UINT)-1)
        {
            /* Buffer too small — grow and retry. */
            g_bufferSize = max(bufferSize, g_bufferSize * 2);
            g_pBuffer = realloc(g_pBuffer, g_bufferSize);
            if (g_pBuffer == NULL)
                break;
            continue;
        }

        {
            RAWINPUT* ri = (RAWINPUT*)g_pBuffer;
            UINT i;
            for (i = 0; i < count; ++i, ri = NEXTRAWINPUTBLOCK(ri))
                ProcessInput(ri);
        }
        /* Do not break — there may be more events in the queue. */
    }
}

/* ... */

case WM_INPUT:
{
    /* Phase 1: read the event carried by this WM_INPUT message. */
    UINT bufferSize = g_bufferSize;
    if (GetRawInputData((HRAWINPUT)lParam, RID_INPUT, g_pBuffer, &bufferSize, sizeof(RAWINPUTHEADER)) != (UINT)-1)
    {
        ProcessInput((RAWINPUT*)g_pBuffer);
    }

    /* Phase 2 (optional): drain any additional events that accumulated in the queue since this message was posted.
     * Recommended for high-frequency devices such as mice at 1000Hz. */
    DrainRawInputQueue();

    return DefWindowProc(hWnd, uMsg, wParam, lParam);
}

Performing a Buffered Read of Raw Input

This sample shows how to read raw input in fixed-rate batches using a periodic timer. WM_INPUT messages are intentionally never dispatched through DispatchMessage — because GetMessage removes messages from the raw input queue before returning, only PeekMessage with explicit message range filters is used, skipping WM_INPUT entirely. All other messages are dispatched normally via DispatchMessage. This keeps all raw input events in the queue where GetRawInputBuffer can drain them all at once on each timer tick. This approach is well-suited for game loops and other applications that process input at a fixed rate rather than reacting to each event individually.

MSG msg;
BOOL running = TRUE;

HWND hWnd = CreateWindowExW(0, L"Message", NULL, 0, 0, 0, 0, 0, HWND_MESSAGE, NULL, NULL, NULL);

RAWINPUTDEVICE rid[2] = {
    { 0x01, 0x02, RIDEV_INPUTSINK, hWnd }, /* mouse */
    { 0x01, 0x06, RIDEV_INPUTSINK, hWnd }, /* keyboard */
};
RegisterRawInputDevices(rid, 2, sizeof(RAWINPUTDEVICE));

/* Drain raw input queue every 16ms (~60Hz) */
SetTimer(hWnd, 1, 16, NULL);

/* Message loop — WM_INPUT is skipped via range filters so it
 * accumulates in the raw input queue for DrainRawInputQueue to drain. */
while (running)
{
    while (PeekMessageW(&msg, NULL, 0, WM_INPUT - 1, PM_REMOVE) ||
           PeekMessageW(&msg, NULL, WM_INPUT + 1, 0xFFFF, PM_REMOVE))
    {
        if (msg.message == WM_QUIT)
        {
            running = FALSE;
            break;
        }

        if (msg.message == WM_TIMER)
        {
            DrainRawInputQueue();
        }

        DispatchMessageW(&msg);
    }

    if (running)
        WaitMessage();
}
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