RE: [GD-Windows] new/delete across DLL's

[Jon W. <hp...@mi...>]

Welcome to DLL hell.

There are two kinds of DLL hell: the Unix hell, where some library can=20
decide to replace malloc() in the global symbol table, and suddenly=20
you're running with some other allocator than you tested your code=20
with; and the Windows hell, where each DLL can run with its own=20
allocator (say, debug vs release vs version 7.0), which means that you=20
have to balance all allocations and deletions.

The only sane way around this that I've found is to base your cross-
DLL object model on factory functions and abstract interfaces, and use=20
"deleteYourself()" as a virtual function to delete an instance (or go=20
all the way and acquire()/release() with ref counting).

You may note that COM does a lot of these things, btw :-)

Also, for the same reasons, inline functions are often a very bad idea=20
for objects that are supposed to live in DLLs. First, because you have=20
to re-compile the user when you change the implementation of the object=20
(so you can't rev the DLL separately unless you take a LOT of care).=20
Second, because if you happen to allocate memory, then the inline may=20
live in one of many different modules. This is especially bad with STL=20
style containers.

Cheers,

				/ h+



> -----Original Message-----
> From: gam...@li...
> [mailto:gam...@li...]On Behalf Of
> Ben Hawes
> Sent: Monday, March 24, 2003 9:08 AM
> To: gam...@li...
> Subject: [GD-Windows] new/delete across DLL's
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> Am I doing something wrong, or is this correct behaviour:
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> in core.dll I have a class CFooBar.
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> in the game exe, I call wibble =3D new CFooBar;
> Later on, within the exe, I call delete wibble; and get an Assert=20
> warning because I'm deallocating from the wrong heap.
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> This seems very strange, that I can only deallocate a class=20
> defined in a DLL from within that DLL, even if the instance was=20
> allocated somewhere else. Am I understanding this correctly, or=20
> am I doing something else to cause the problem? Is there any way=20
> round this?
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> [ cruise / casual-tempest.net / transference.org ]
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