C++ system tray only program

2
votes

After checking Microsoft's documentation on system tray icons (that I could find):

Shell_NotifyIconA function

NOTIFYICONDATAA structure

I've noticed that a window handle (HWND) is REQUIRED. This is very bad for what I'm trying to accomplish, as I'm looking to create a program that only reacts to the system tray: it doesn't "minimize" the window to the tray, it just uses notifications (clicking/right clicking on the icon) to interact.

How would I go about doing this?

1
c++winapisystem-tray
You can create a window and never show it. - tkausl
Oh my god, is this seriously how it's meant to work? Am I unable to pass a nullptr or anything? - ZeroZ30o
@ZeroZ30o the point is that the window you pass is the target of the messages. It's not uncommon in Win32 to use windows just for message passing - there's even the concept of message-only windows (with no actual associated drawing surface or anything). - Matteo Italia
You can use a Message-Only window: "A message-only window enables you to send and receive messages. It is not visible, has no z-order, cannot be enumerated, and does not receive broadcast messages. The window simply dispatches messages." - Remy Lebeau
@RemyLebeau Unfortunately, a message-only window doesn't receive WM_QUERYENDSESSION and other broadcast messages. So if you want to gracefully shutdown, instead of being terminated, a regular hidden window would be a better choice. - zett42

1 Answers

4
votes

The Windows 7 SDK contains an example called NotificationIcon. This example contains a line

ShowWindow(hwnd, nCmdShow);

in its wWinMain function. The effect of this call is that you see a program window.

Just change this line to

ShowWindow(hwnd, SW_HIDE);

to hide the program window and only display the icon in the system tray. As others have pointed out the program needs a program window, even if it is not visible.