4 ms·

Hmm... yeah, that does sound very similar. Why does Windows need kernel-to-user callbacks in the first place then? Now I'm thinking it shouldn't even be necess

• deleted 13y ago
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• quotemstr 13y ago
  You may be interested in http://mista.nu/research/mandt-win32k-slides.pdf http://mista.nu/research/mandt-win32k-slides.pdf
  • wfunction 13y ago
    Thanks, I took a look at that... but it doesn't seem to quite explain what I meant. I was thinking more like, there's no need for SendMessage() to go from user->kernel->user, even when it's on the same thread. It could just do a system call to get the wndproc for the given window, then call the wndproc from user-mode directly. Wouldn't that completely avoid needing to call back into user-mode from kernel mode?
    • yuhong 13y ago
      It does this already when the window is on the same thread if no window hooks are installed. When the window is on a different thread, it is GetMessage or PeekMessage on the target thread that notices the sent message and does the user-mode callback to call the window procedure.