DLL using objects from calling EXE

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dllproc/base/using_shared_memory_in_a_dynamic_link_library.asp

I don''t know why your dll can''t use memory allocated by the calling process, since the dll''s memory space is mapped to the caller''s, but maybe your modules are using seperate heaps.

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- outRider -

I have changed my approach a bit. I would like to convert all my subsystem classes into singletons, which are initialized at the start of the game. These singleton subsystems would then be used by the game-specific classes defined in the DLL. Unfortunately, the DLL and the EXE would each have their own instance of the singleton.

Is there a clean (or semi-clean) way to allow the DLL and EXE to share the same singleton object?

-Mike

quote:

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from the MSDN:
Win32 DLLs are mapped into the address space of the calling process. By default, each process using a DLL has its own instance of all the DLLs global and static variables.

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So does this mean that a DLL will use the calling executable''s memory space? If so, then why does using a singleton class with both the EXE and DLL result in two seperate singletons created for each? How would I get them to share the same singleton instance?

outRider, I looked through that article, but it seems to be oriented towards sharing a single DLL''s memory across multiple processes, which isn''t quite what I think I want.


Any thoughts?

Mike

doctorsixstring: If you find any decent solution pleas tell me becouse I have almost exact same problem.

You should never let your fears become the boundaries of your dreams.

quote:

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Original post by Anonymous Poster
what exactly do you mean by...

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Basically, my main executable initializes my singletons, and then I load the DLL and call its object creation functions (i.e. Game* CreateGameObj()). I set breakpoints in the DLL and notice that Gfx::Instance() == 0 (Gfx is one of my singleton subsystem classes). In other words, the singleton is never created in the DLL.

As I was typing, I may have just realized my problem. Should I initialize my singletons AFTER loading the DLL w/ LoadLibrary()? I have a slightly non-traditional feature in my singleton classes - the first call to GetInstance() will NOT create the singleton class, but will return NULL until the user runs SingletonClass::Init(). I am using this so that I may do all my subsystem initialization at one time (as well as cleanup using SingletonClass::Destroy()).

Also, I have been thinking about not using a DLL after all. It may be easier to simply have all the game code in the main executable. This would mean I would have to put the same WinMain() code in every individual game that uses my engine, but that may not really be much of a price to pay. What do you guys think? Is using a DLL worth it?

-Mike

[edited by - doctorsixstring on October 13, 2003 2:06:06 PM]