C++ Def and Non-Def file - Function Signature - help!
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Hi there, I had a question. I just noticed the availability of module definition file *.def. I had a few doubts. The current scenario: ------------------------- *The wrapper dll's library and dll is place under the SDK folder. The lib file is included in the project under the visual studio path settings. SDK -> Wrapper Dll SDK code: ------------- #include "wrapper_dll.h" extern "C" __declspec(dllimport) double TestA(double a, double b); Wrapper DLL Code: ------------------------ #define extern "C __declspec(dllexport) EXTERN double WINAPI TestA(double a, double b); When you built in into a dll, when you view the dll dependecies, you will notice this (example): Ordinal = 1 (0x0001) Hint = 0 (0x0000) Function = _TestA@20 EntryPoint = 0x0000101E *The build dll, lib and header file is past to the SDK team to call it. ============================================================ Now, I want to implement def file: SDK (cannot modified, coz done by someone else and different team) but it still calls the Wrapper dll. SDK code (same with on top): ----------------------------------- #include "wrapper_dll.h" extern "C" __declspec(dllimport) double TestA(double a, double b); New Wrapper Dll code: --------------------------- wrapper_dll.cpp: double TestA(double a, double b) { return a + b / 10; } wrapper_dll.h: #pragma once // what does pragma means anyway?? any idea??? double TestA(double a, double b); wrapper_dll.def: LIBRARY Wrapper_Dll EXPORTS TestA Now, when i view this dll dependencies, it appears to be like this: Ordinal = 1 (0x0001) Hint = 0 (0x0000) Function = TestA EntryPoint = 0x000128A7 *problem is the Function name is changed, entrypoint number is change... will this cause problem for the SDK when calling. ============================================================ I need to make sure SDK should be recompiled. I just have to replace the new wrapper dll, lib and .h into the existing files that is part of the SDK folder. Should i be using def or not def? The current old code is using no def file. Means the sdk will have __declspec(dllimport) and the wrapper will have __declspec(dllexport), and the #include "Wrapper_dll.h" is still part of it of the sdk. Please help! Module definition file is indeed easier for us as a coder to code. But i just want to see what is the advantages of using def over the others. Thanks. Regards, Chua Wen Ching :p
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Hi there, I had a question. I just noticed the availability of module definition file *.def. I had a few doubts. The current scenario: ------------------------- *The wrapper dll's library and dll is place under the SDK folder. The lib file is included in the project under the visual studio path settings. SDK -> Wrapper Dll SDK code: ------------- #include "wrapper_dll.h" extern "C" __declspec(dllimport) double TestA(double a, double b); Wrapper DLL Code: ------------------------ #define extern "C __declspec(dllexport) EXTERN double WINAPI TestA(double a, double b); When you built in into a dll, when you view the dll dependecies, you will notice this (example): Ordinal = 1 (0x0001) Hint = 0 (0x0000) Function = _TestA@20 EntryPoint = 0x0000101E *The build dll, lib and header file is past to the SDK team to call it. ============================================================ Now, I want to implement def file: SDK (cannot modified, coz done by someone else and different team) but it still calls the Wrapper dll. SDK code (same with on top): ----------------------------------- #include "wrapper_dll.h" extern "C" __declspec(dllimport) double TestA(double a, double b); New Wrapper Dll code: --------------------------- wrapper_dll.cpp: double TestA(double a, double b) { return a + b / 10; } wrapper_dll.h: #pragma once // what does pragma means anyway?? any idea??? double TestA(double a, double b); wrapper_dll.def: LIBRARY Wrapper_Dll EXPORTS TestA Now, when i view this dll dependencies, it appears to be like this: Ordinal = 1 (0x0001) Hint = 0 (0x0000) Function = TestA EntryPoint = 0x000128A7 *problem is the Function name is changed, entrypoint number is change... will this cause problem for the SDK when calling. ============================================================ I need to make sure SDK should be recompiled. I just have to replace the new wrapper dll, lib and .h into the existing files that is part of the SDK folder. Should i be using def or not def? The current old code is using no def file. Means the sdk will have __declspec(dllimport) and the wrapper will have __declspec(dllexport), and the #include "Wrapper_dll.h" is still part of it of the sdk. Please help! Module definition file is indeed easier for us as a coder to code. But i just want to see what is the advantages of using def over the others. Thanks. Regards, Chua Wen Ching :p
Hail again, If you provide .dll, .lib and .h that means you link to a DLL implicitly and you don't need .def file then. Using a module definition file makes sense only if you want to find function entry point during run-time by using GetProcAddress and referencing a function by an ordinal rather than a name.