How to access gsdll32.dll in C++ or C++/CLI project

Question

I have written a program that creates chess diagrams using post script.  I want to convert the resulting *.eps file to an equivalent *.jpg file using ghost script.  I have succeeded in doing this in a C# project but I cannot get it to work in C++ or C++/CLI, either one.  The problem is in getting access to the gsdll32.dll methods.

In C# I use this code:
        [DllImport ("gsdll32.dll", EntryPoint = "gsapi_new_instance")]
        private static extern int CreateAPIInstance (out IntPtr instance, IntPtr caller);
My attempts to use DllImport in C++ have failed.

In a C++/CLI project I get the following error when trying to add a reference:

Could not add a reference to 'S:\UseGhostScript\bin\Debug\gsdll32.dll' as it is not of a type or version current project can use.

In a C++ project I added the gsdll32.dll as a 'Solution item' and when building get the error message:

Error LNK1107 invalid or corrupt file: cannot read at 0x2B8 UseGhostScriptConsole S:\ScruffySoft\UseGhostScriptConsole\gsdll32.dll

So the question is: how do I get access to the ghost script DLL?

Thanks,
Dick

Answer 1

Do you have the associated .h and .lib files for this library?

It is also possible to use [DllImport] in C++/CLI (https://docs.microsoft.com/en-us/cpp/dotnet/calling-native-functions-from-managed-code?view=vs-2019), but make sure that you choose the right configuration: 32- or 64-bit.

You can also consider the method based on LoadLibrary, GetProcAddress, etc.

An intermediate solution is to build a C# Class Library, where you already know how to access the DLL, and reference it in C++/CLI. The public classes from C# can be used in C++/CLI directly.

Answer 2

Still working on the C++ solution but the the idea of creating a C# library works fine.  I don't know why I did not think of that myself.