C++ code called from C#

  • Thread starter Thread starter Daniel P.
  • Start date Start date
D

Daniel P.

I have some legacy code I would like to wrap by some new managed C++
classes, put them all into a DLL and then call the managed classes from a C#
app.

Can anyone recommend me a link with some info about this?

Also, can I statically link my DLL to my C# application or I have to ship
the Managed C++ DLL with the C# exe appllication?

Thanks!
 
Daniel P. said:
I have some legacy code I would like to wrap by some new managed C++
classes, put them all into a DLL and then call the managed classes from a C#
app.
Click to expand...

The second part of your question is a gimme. Once you have an MC++ object,
any .Net code in any CLS compliant language can make use of it. Now it is
true that some languages don't support all of the types supported by MC++
(unsigned's as I recall) that is often little more than a nit.
Can anyone recommend me a link with some info about this?
Click to expand...

As to the first part of your question you can use "IJW" or it just works so
that a managed C++ member function can call an unmanged C++ function. The
MC++ compiler writes the code to hop the fence between the two environments.

For tips on interoperability take a look at this:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vcmxspec/html/vcmg_part2start.asp

and this

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vcmxspec/html/vcmg_part2start.asp

I like the treatment of interoperability in the book "Essential Guide to
Managed Extensions for C++" (Apress) by Challa and Laksberg of the VC team.
Also, can I statically link my DLL to my C# application or I have to ship
the Managed C++ DLL with the C# exe appllication?
Click to expand...

Well, if you want to call into a DLL, you'll have to ship it. :-) As to the
linking mechanism used by C# sorry but I don't know what your options are.
That'll probably be answered in the C# group.

Regards,
Will
 
Well, if you want to call into a DLL, you'll have to ship it. :-) As
to the linking mechanism used by C# sorry but I don't know what your
options are. That'll probably be answered in the C# group.
Click to expand...

Using VS2002/2003, you'll need to ship two physical files. The tools do
not expose a way to link them into one image.

In VS2005, you'll be able to compile your code as .netmodules and link
them into a single-file assembly.

Thanks,
 
Tarek,

IMO the linker (link.exe) refuses to merge pure .netmodules (C#, VB, C++
/clr:safe or /clr:pure) and .netmodules containing native code (C++
/clr)into a single assembly .
So in the case you wrap native code with managed code, you will always need
the separate mixed code assembly, or am I missing something?

Willy.
 
Willy said:
IMO the linker (link.exe) refuses to merge pure .netmodules (C#, VB, C++
/clr:safe or /clr:pure) and .netmodules containing native code (C++
/clr)into a single assembly .
So in the case you wrap native code with managed code, you will always
need the separate mixed code assembly, or am I missing something?
Click to expand...

If it comes from another language, you'll pass a .netmodule to the linker.
If it comes from C++, you're almost always better off passing object files
rather than .netmodule files to the linker.

Remember that object files can have metadata too, so other compilers can
reference them.
 
Brandon,

Thanks for the prompt reply.

I just tried to link a C# netmodule and a mixed mode .netmodule (C++
14.00.40603) and this is what the linker say's...
fatal error LNK1302: unable to link .netmodule containing native code
Click to expand...

So it looks like we should never use mixed mode .netmodules (using C++) to
be passed to the linker, but instead link the .obj files.

Willy.
 
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