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    <p>The problem is that your header file meant for compilation into a DLL contains code! So "main.exe" exectutes a local copy of the inline functions (such as Base::sys), but the actual implementation of "Base::setSystem" is compiled into the DLL. So when main invokes the "setSystem" call, it calls the Base::setSystem linked into the DLL. But when it compiles Base::sys, it sees that an inline implementation exists and uses that.</p> <p>In other words, you have two copies of "Base" floating around. One that lives in the EXE and another that lives in the DLL. And the inline functions confuse the compiler and linker as to which version to invoke.</p> <p>Don't put inline functions (or code for that matter) in a header file where the implementation is meant to live in a DLL.</p> <p>Easy fix:</p> <pre><code>// base.h (gets included by main) class Base { private: static Filesystem * filesystem; static Logger * logger; static System * system; public: static void setFilesystem(Filesystem * filesystem_); static void setApplication(Application * application_); static void setLogger(Logger * logger_); static void setSystem(System * system_); static Filesystem * fs(); static Logger * log(); static System * sys(); }; // base.cpp (gets compiled only within the DLL System* Base::sys() { return system; } // repeat "get" function for "log" and "fs" as well </code></pre> <p>Right fix:</p> <p>You really, really, really should not be attempting to export C++ classes from DLLs. It's allowed, but gets complicated really quick when you start inlining code in header files and changing interfaces in different versions of the DLL.</p> <p>A better approach is to export a pure "C" library from a DLL. And don't expose the internals in header files. OR, if you do want to export C++ classes, do it with COM interfaces. Then all you are doing is putting an interface declaration into your header file.</p>
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    1. POuse static class variable/function across dlls
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    1. USselbie
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    1. COI changed everything as you said and also created a static library because It won't compile (link errors) without putting these files in both projects. But it still doesn't work. My problem is, I am trying to have the static variables across the dlls. Main application sets up the static variables using the setters and all the dlls should have the "global" variables accessed through getters. Is it possible?
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    2. COIt certainly is possible. What is the link error - it is possibly indicative of a real problem. You are properly exporting these functions from the DLL, right? Either with __dllexport attribute or a .DEF file.
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    3. COOk. I have a static library "Base.lib" that stores the Base class symbols. The "engine.exe" has to initialize the variables of the Base class using the setters. And, the DLL uses these variables using the getters. Getters and setters do not have to be exported but the static variables do have to. So, I have added `#pragma data_seg(".base_seg")` (i changed the source code for you to visually easily see it). It doesn't work though.
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