How to block right mouse button and convert it to middle mouse button without delay (like AutoHotkey)?

Question

I’m trying to remap the right mouse button to act as the middle mouse button in C++ on Windows.

What I did

I wrote code using Raw Input (see below).
My code successfully sends a middle click when I press the right button.
But the original right click action still happens at the same time, so I end up with both right click and middle click firing.

I also tried using a WH_MOUSE_LL low-level mouse hook:

This can block the right button completely.
However, it introduces a small delay, and the behavior does not feel as smooth or natural as AutoHotkey’s remapping.

What I want

When I press the right mouse button, I want to completely block the original right click.
Instead, it should act exactly like the middle mouse button.
It should feel instant (no noticeable delay), as natural as if I physically pressed the middle button.

My ultimate goal is to achieve AutoHotkey-level remapping in C++:

Right button is completely suppressed (never reaches applications).
Only middle button is sent instead.
The behavior should be instant and natural, with no noticeable delay, just like if I physically pressed the middle button.

My current code (Raw Input version)

#include <windows.h>
#include <iostream>

// SendInput to simulate middle click
void SendMiddleClick(bool down) {
    INPUT input = { 0 };
    input.type = INPUT_MOUSE;
    input.mi.dwFlags = down ? MOUSEEVENTF_MIDDLEDOWN : MOUSEEVENTF_MIDDLEUP;
    SendInput(1, &input, sizeof(INPUT));
}

// Window procedure
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
    if (msg == WM_INPUT) {
        UINT dwSize = 0;
        GetRawInputData((HRAWINPUT)lParam, RID_INPUT, NULL, &dwSize, sizeof(RAWINPUTHEADER));
        if (dwSize > 0) {
            BYTE* lpb = new BYTE[dwSize];
            if (GetRawInputData((HRAWINPUT)lParam, RID_INPUT, lpb, &dwSize, sizeof(RAWINPUTHEADER)) == dwSize) {
                RAWINPUT* raw = (RAWINPUT*)lpb;
                if (raw->header.dwType == RIM_TYPEMOUSE) {
                    auto flags = raw->data.mouse.usButtonFlags;
                    if (flags & RI_MOUSE_RIGHT_BUTTON_DOWN) SendMiddleClick(true);
                    if (flags & RI_MOUSE_RIGHT_BUTTON_UP)   SendMiddleClick(false);
                }
            }
            delete[] lpb;
        }
    }
    return DefWindowProc(hwnd, msg, wParam, lParam);
}

int main() {
    WNDCLASS wc = { 0 };
    wc.lpfnWndProc = WndProc;
    wc.hInstance = GetModuleHandle(NULL);
    wc.lpszClassName = TEXT("RawInputDemo");
    RegisterClass(&wc);

    HWND hwnd = CreateWindow(wc.lpszClassName, TEXT("Raw Input Window"),
        WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT,
        300, 200, NULL, NULL, wc.hInstance, NULL);

    RAWINPUTDEVICE rid;
    rid.usUsagePage = 0x01;
    rid.usUsage = 0x02;
    rid.dwFlags = RIDEV_INPUTSINK;
    rid.hwndTarget = hwnd;
    RegisterRawInputDevices(&rid, 1, sizeof(rid));

    MSG msg;
    while (GetMessage(&msg, NULL, 0, 0)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return 0;
}

Side note, changing the "default" expected mouse input behavior away from normal might surprise your users a lot. I recommend you don't do this at all. — Pepijn Kramer
– Pepijn Kramer, Commented Sep 22 at 8:00
Raw Input is fast and can monitor input, but not reject it. A low-level hook is slow, but it can filter input from being passed to the system for further processing. — IInspectable
– IInspectable, Commented Sep 22 at 12:02
Autohotkey is an open source tool written in C++. You can have a look on their source code to see how they solved this problem and get some inspiration. Though it may require some search to find the related pieces for the mouse handling. — Thibe
– Thibe, Commented Sep 23 at 9:33

Bulletmagnet · Accepted Answer · 2025-09-22 05:49:56Z

2

Don't bother with raw input. Replace WM_RBUTTONDOWN with WM_MBUTTONDOWN:

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
    if (msg == WM_RBUTTONDOWN) {
        return DefWindowProc(hwnd, WM_MBUTTONDOWN, wParam, lParam);
    }
    return DefWindowProc(hwnd, msg, wParam, lParam);
}

You may need to do the same with WM_RBUTTONUP.

answered Sep 22 at 5:49

Bulletmagnet

6,0913 gold badges31 silver badges60 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

IInspectable Sep 22 at 12:05

The question is asking for a way to do this system-wide (not just for a single window).

Collectives™ on Stack Overflow

How to block right mouse button and convert it to middle mouse button without delay (like AutoHotkey)?

What I did

What I want

My current code (Raw Input version)

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

What I did

What I want

My current code (Raw Input version)

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related