Dll - Export Function - EntryPointNotFoundException

[Jeffrey Walton]

Hi All,

Sorry about dropping thish on M.P.D.L.CSharp. There is no M.P.D.L.VC.
So I hope someone has come across the issue...

How does one export a function (not a class) in a managed Dll?

I'm catching a System.EntryPointNotFoundException. dumpbin confirms
that the Dll is not exporting the function.

Does not work:
* declaring method as public: error C2059: syntax error : 'public'
* __declspec( dllexport ): incompatible with /clr and /clrur
* .def file: fatal link error LNK1310: Exports not supported for pure
MSIL image

Thanks,
Jeff

////////////////////////
// Test Header
bool Test( array<byte>^ );

////////////////////////
// Test Implementation
bool Test( array<byte>^ a ) {...}

 

[Ignacio Machin ( .NET/ C# MVP )]

Hi All,

Sorry about dropping thish on M.P.D.L.CSharp. There is no M.P.D.L.VC.
So I hope someone has come across the issue...

How does one export a function (not a class) in a managed Dll?

You cannot do it AFAIK
A managed dll export only types.
You can create a wrap and then you get a CCW (COM Callable Wrapper).
but even that is a COM DLL, not a win32 one.
The only solution I see is for you to create your .NET dll, export it
as CCW and then create a native dll that instantiate the COM and allow
a call to the method you need as a function

 

[Pavel Minaev]

Hi All,

Sorry about dropping thish on M.P.D.L.CSharp. There is no M.P.D.L.VC.

There is, microsoft.public.dotnet.languages.vc:

http://groups.google.com/group/microsoft.public.dotnet.languages.vc/topics

How does one export a function (not a class) in a managed Dll?

You can't.

 

[Jeffrey Walton]

Hi Pavel,

There is, microsoft.public.dotnet.languages.vc:

Thanks. When I looked yesterday, Google did not return it. Odd???

You can't.

Is that a 'you can't' because Microsoft tools do not do it?

Jeff

 

[Jeffrey Walton]

Hi Ignacio,

You cannot do it AFAIK

Is that a 'you cannot' because Microsoft tools don't do it?

I asked Pavel the same. The reason I ask is that I have an
experimental linker. While developing it, I picked up a lot of PE
format knowledge. So it may be a question of finding the right tool
for the job. Naively, I'm going to say that adding a Export directory
to the PE and a thunk in the .text section is quite doable.

Jeff

 

[Pavel Minaev]

Hi Ignacio,


Is that a 'you cannot' because Microsoft tools don't do it?

I asked Pavel the same. The reason I ask is that I have an
experimental linker. While developing it, I picked up a lot of PE
format knowledge. So it may be a question of finding the right tool
for the job. Naively, I'm going to say that adding a Export directory
to the PE and a thunk in the .text section is quite doable.

You can probably do it, but that wouldn't be a pure managed assembly
anymore (similarly to what C++/CLR produces). At any rate, it wouldn't
be any different from just having a separate unmanaged assembly
redirecting calls to a managed one.

 

[Jeffrey Walton]

Hi Pavel,

{SNIP]

The reason I ask is that I have an
experimental linker. While developing it, I picked up a lot of PE
format knowledge. So it may be a question of finding the right tool
for the job. Naively, I'm going to say that adding a Export directory
to the PE and a thunk in the .text section is quite doable.

You can probably do it, but that wouldn't be a pure managed assembly
anymore (similarly to what C++/CLR produces). At any rate, it wouldn't
be any different from just having a separate unmanaged assembly
redirecting calls to a managed one.

I think in the end that though possible, I believe it will create more
problems then it solves. My need was to keep a consistent interface
(from an unmanaged Dll) when wrapping an AES crpyo engine. When I ran
the managed AES benchmarks, AesCryptoServiceProvider performed like a
turd.

Jeff