Hi
I was wanting to do some work on x11drv dll separation. The last remaining dll separation between x11drv and ntdll is VIRTUAL_SetFaultHandler. This is called from X11DRV_DIB_CreateDIBSection, where it tries to set the fault handler to X11DRV_DIB_FaultHandler, with addr=dm.dmBits and arg=res.
From reading the code it seems that this is done because it is not known whether the calling app requires read or write access to the data in bmp. If the app then tries to read or write and doesn't have the appropriate access, this will generate an exception which will then raise the X11DRV_DIB_FaultHandler which would then set the appropriate access, in a way that ensures data gets handled correctly.
I presume I'm misunderstanding this, because looking at MSDN for CreateDIBSection, it says: The CreateDIBSection function creates a device-independent bitmap (DIB) that applications can write to directly. and further down... Windows NT: You need to guarantee that the GDI subsystem has completed any drawing to a bitmap created by CreateDIBSection before you draw to the bitmap yourself. Access to the bitmap must be synchronized. Do this by calling the GdiFlush function.
So it would seem apps could always be given read-write access to this bitmap.
Why is the special fault handler needed? What is the best way to approach getting rid of it?
David