Функция Shell_NotifyIcon

BOOL Shell_NotifyIcon(
  _In_ DWORD           dwMessage,
  _In_ PNOTIFYICONDATA lpdata
);

#include <windows.h>
 
const int width = 640;
const int height = 480;
 
NOTIFYICONDATA pnid;
 
LRESULT WINAPI WindowProc(HWND hWnd, UINT uMsg, WPARAM wp, LPARAM lp)
{
    switch (uMsg)
    {
    case WM_CLOSE:
        Shell_NotifyIcon(NIM_ADD, &pnid);
        ShowWindow(hWnd, SW_HIDE);
        break;
    case 15666:
        if (lp == WM_LBUTTONDBCLK)
        {
            Shell_NotifyIcon(NIM_DELETE, &pnid);
            ShowWindow(hWnd, SW_SHOW);
        }
        break;
    default:
        return DefWindowProc(hWnd, uMsg, wp, lp);
        break;
    }
}
 
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE, LPSTR cmdLine, int)
{
    HWND hMainWnd;
    MSG uMsg;
 
    char *text = "Text for tooltip";
 
    WNDCLASSEX wc;
 
    memset(&wc, 0, sizeof(WNDCLASSEX));
 
    wc.cbSize = sizeof(WNDCLASSEX);
    wc.hbrBackground = (HBRUSH)GetStockObject(0);
    wc.hCursor = LoadCursor(0, IDC_ARROW);
    wc.hIcon = LoadIcon(0, IDI_APPLICATION);
    wc.hInstance = hInstance;
    wc.lpfnWndProc = &WindowProc;
    wc.lpszClassName = "trayer";
 
    RegisterClassEx(&wc);
 
    hMainWnd = CreateWindow("trayer", "Trayer", WS_OVERLAPPEDWINDOW,
        (GetSystemMetrics(SM_CXSCREEN) - width) / 2, (GetSystemMetrics(SM_CYSCREEN) - height) / 2,
        width, height, 0, 0, hInstance, 0);
 
    ShowWindow(hMainWnd, SW_SHOW);
 
    pnid.cbSize = sizeof(pnid);
    pnid.hWnd = hMainWnd;
    pnid.hIcon = LoadIcon(0, IDI_APPLICATION);
    pnid.uID = 15;
    pnid.uFlags = NIF_ICON | NIF_TIP | NIF_MESSAGE;
    pnid.uCallbackMessage = 15666;
    memcpy(pnid.szTip, text, 17);
 
    while (GetMessage(&uMsg, 0, 0, 0))
    {
        TranslateMessage(&uMsg);
        DispatchMessage(&uMsg);
    }
 
    return uMsg.wParam;
}