Create a dll from a .h file
Hi
I hope i am posting in the correct place. I am developing a web based application in asp.net and am in the process of trying to integrate a third party application. The third party application is supplied in the form of a.h file.
The example they provided is also in C++, which uses the.h file in question. I would like to create adll from this.h file which i can then call from my .Net code. They have provided me with the following advice about creating a wrapper, which i must admit is a little beyond my current C++ understanding. I would be grateful if someone could explain the steps a little clearer to me or suggest a possible solution. I am currently developing in Visual Studio .Net 2003.
Notes about wrapping the Paper SDK for VS7/VS8:
- The Paper SDK lib\dll directory must be in your path.
- GAPATHOME must be properly set to the GAPAT directory installed by the FDT (or a copy of that directory).
- The Paper SDK cannot be linked to VC8 libraries; the VC6 linker must be employed. In other words, both the demo code AND the actual Paper SDK libraries themselves use template library functions which VC8 does not know about.
- I wrapped Paper SDK functionality in a VC6 DLL exposing it via primitive types (char *, int, etc) and then called that VC6 DLL from
VC8 C++ (mixing managed and unmanaged code). The VC8 C++ assembly is then easily referenced by/callable from .NET 2.0 C# or other managed code.
- Don't forget that memory allocated in a VC6 DLL must be freed by that DLL (cannot be freed by VC8 code). Your VC6 wrapper DLL has to expose a Delete function if it returns pointers to memory it has allocated.
- You can set GAPATHOME at runtime (using SetEnvironmentVariable) without having it already set in the environment if (and only if) you dynamically load the DLL that is linked to the Paper SDK components, using LoadLibrary and GetProcAddress. If the DLL's load when your code (app or DLL) is loaded, and then GAPATHOME is set afterwards, it is too late.
- A similar trick could be employed (with setcwd to set current
directory) to avoid having to have the Paper SDK lib\dll directory on your PATH.
Thanks in advance
Mike
