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I have an app that uses functions inside a dll. I would like the dll to get a variable hInstance from the app so when the dll is loaded it has the value assigned to an hInstance vraible in the dll?
Is this possible?if so how would i go about doing this?
Cheers in Advance
Andy
I'm not sure if GetCurrentProcess will return a handle to the DLL or the EXE. You'd have to use DuplicateHandle anyway.
If this does not work, you have to require the app to call a init-function and supply it's own instance handle.
the dl currently uses an init function to get the handle and this works fine until the focus is taken off the app window and onto another, the dll seems to lose the handle and reset itself to NULL along with other static variables!?
Hence why i wondered if you could get the dll to look at an apps varibales.
I'll have a go with GetCurrentProcess.
Cheers
Andy
"seems to loose the handle" ???
Do you mean, after returning to the process that uses the DLL the static variables are resetted??
Or are the variables uninitialized in another process that uses the same DLL?
This is because DLLs don't have their own memory, but rather use the one of the app they are linked too. This means there is one set of DLL static variables for every app that uses the DLL. If you want that those variables are the same for all applications that use them (you probably don't want, because HWND is specific to every application), you should insert this line after the data segment:
#pragma comment(linker, "/SECTION:SHARDATA, RWS")
but watch out: this also means that if one application changes the variables it can cause problems with other applications. Also, you'll have thread-synchronization problems, so you should know how to use critical sections, the Interlocked* function family, mutexes, events and semaphores (search for these things in MSDN).