Unmanaged Exports: Cannot compile assembly

Question

I want to create a .NET assembly that can be accessed from unmanaged code (Delphi 5).

I have found Unmanaged Exports and followed the steps there but I am unable to successfuly compile even the basic example:

using RGiesecke.DllExport;

namespace DelphiNET
{
    public class Class1
    {
        [DllExport("add")]
        public static int Add(int left, int right)
        {
            return left + right;
        }
    }
}

DelphiNET.csproj project file:

...
<ItemGroup>
  <Compile Include="Class1.cs" />
  <Compile Include="DllExport\DllExportAttribute.cs" />
  <Compile Include="Properties\AssemblyInfo.cs" />
</ItemGroup>
<Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
<Import Project="DllExport\RGiesecke.DllExport.targets" />
...

Here is the error:

------ Build started: Project: DelphiNET, Configuration: Release Any CPU ------
c:\WINDOWS\Microsoft.NET\Framework\v3.5\Csc.exe /noconfig /nowarn:1701,1702 /errorreport:prompt /warn:4 /define:TRACE /debug:pdbonly /filealign:512 /optimize+ /out:obj\Release\DelphiNET.dll /target:library Class1.cs DllExport\DllExportAttribute.cs Properties\AssemblyInfo.cs

Compile complete -- 0 errors, 0 warnings
DelphiNET -> C:\DelphiNET\bin\Release\DelphiNET.dll
ILDasm: calling 'C:\Program Files\Microsoft SDKs\Windows\v6.0A\Bin\ildasm.exe' with /quoteallnames /nobar "/out:C:\Documents and Settings\Lukas\Local Settings\Temp\tmp29F\DelphiNET.il" "C:\DelphiNET\bin\Release\DelphiNET.dll"
C:\DelphiNET\bin\Release\DelphiNET.dll : warning EXP0009: Platform is AnyCpu, generating creating binaries for each CPU platform in a separate folder...
ILAsm: calling 'c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\ILAsm.exe' with /nologo "/out:C:\DelphiNET\bin\Release\x86\DelphiNET.dll" "C:\Documents and Settings\Lukas\Local Settings\Temp\tmp29F\DelphiNET.x86.il" /DLL "/resource=C:\Documents and Settings\Lukas\Local Settings\Temp\tmp29F\DelphiNET.res"  /optimize  
C:\DelphiNET\DllExport\RGiesecke.DllExport.targets(8,5): error : 
C:\DelphiNET\DllExport\RGiesecke.DllExport.targets(8,5): error : Assembling 'C:\Documents and Settings\Lukas\Local Settings\Temp\tmp29F\DelphiNET.x86.il'  to DLL --> 'C:\DelphiNET\bin\Release\x86\DelphiNET.dll'
C:\DelphiNET\DllExport\RGiesecke.DllExport.targets(8,5): error : Source file is ANSI
C:\DelphiNET\DllExport\RGiesecke.DllExport.targets(8,5): error : 
C:\DelphiNET\DllExport\RGiesecke.DllExport.targets(8,5): error : Assembled method RGiesecke.DllExport.DllExportAttribute::.ctor
C:\DelphiNET\DllExport\RGiesecke.DllExport.targets(8,5): error : Assembled method RGiesecke.DllExport.DllExportAttribute::.ctor
C:\DelphiNET\DllExport\RGiesecke.DllExport.targets(8,5): error : Assembled method RGiesecke.DllExport.DllExportAttribute::.ctor
C:\DelphiNET\DllExport\RGiesecke.DllExport.targets(8,5): error : Assembled method RGiesecke.DllExport.DllExportAttribute::get_CallingConvention
C:\DelphiNET\DllExport\RGiesecke.DllExport.targets(8,5): error : Assembled method RGiesecke.DllExport.DllExportAttribute::set_CallingConvention
C:\DelphiNET\DllExport\RGiesecke.DllExport.targets(8,5): error : Assembled method RGiesecke.DllExport.DllExportAttribute::get_ExportName
C:\DelphiNET\DllExport\RGiesecke.DllExport.targets(8,5): error : Assembled method RGiesecke.DllExport.DllExportAttribute::set_ExportName
C:\DelphiNET\DllExport\RGiesecke.DllExport.targets(8,5): error : 
C:\DelphiNET\DllExport\RGiesecke.DllExport.targets(8,5): error : ***** FAILURE ***** 
C:\DelphiNET\DllExport\RGiesecke.DllExport.targets(8,5): error : 
Done building project "DelphiNET.csproj" -- FAILED.
========== Build: 0 succeeded or up-to-date, 1 failed, 0 skipped ==========

OS: WinXPSP3, Microsoft Visual C# 2008 Express Edition with SP1, .NET 3.5 SP1

Any idea what's wrong? Thanks.

---

Edit 23:40:

I have found the bug. It is in the name of the function - add and Add are too same. When you change one of them, it works.

Answer 1

Incidentally, I just updated the archive. You can even get it all laid out for you, when you take this instead.

It's a project template that sets everything up and should work just fine.

I did find some points in the previous version, where I made some assumptions that weren't always true. And one potential problem with my previous implementation was the /optimize switch which is used for release configurations. Sometimes ILAsm would choke on the IL in that case, I haven't seen that with the new version.

Answer 2

Just in case someone will meet the same problems...

Some errors on my side:

file: DllExportAttribute.cs

public CallingConvention CallingConvention { get; set; }
public string ExportName { get; set; }

file: $projectname$.csproj

<Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets"/>  <!-- not working -->
<!-- change to -->
<Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets"/> <!-- working -->

Those are easy to fix.

Here is one pretty serious. When making implib from resulting \x86\MyDll.dll - the name of dll in lib changes to \MyDll.dll ... you can make tdump MyDll.dll and will get in exports section "\MyDll.dll" instead of "MyDll.dll".

Because of this problem dll can't be found by the soft that use resulting lib... in my situation it can be found only in c:\MyDll.dll

Solved by making "coff2omf -lib:ca MyDll.lib" on the initial lib. But before that spent a day for looking solution...