MinHook: The Whole Hook in a Few Calls

/* typedef of the target's signature */
typedef int (WINAPI *MBW_t)(HWND,LPCWSTR,LPCWSTR,UINT);
MBW_t real_MessageBoxW = NULL;

int WINAPI hook_MessageBoxW(HWND h, LPCWSTR text,
                            LPCWSTR cap, UINT type) {
    /* observe / modify, then call through */
    return real_MessageBoxW(h, L"[hooked]", cap, type);
}

MH_Initialize();
MH_CreateHook(&MessageBoxW, &hook_MessageBoxW,
              (LPVOID*)&real_MessageBoxW);  /* fills trampoline ptr */
MH_EnableHook(&MessageBoxW);

• real_MessageBoxW points at the trampoline — one clean call reaches the genuine API.