Interface to C++ (unmanaged) DLL and std::string or std::wstring

[Howie Meier]

Hallo NG,

i can call functions from a native C++-dll wich uses "const char *" as
stringtype via P/Invoke without problems. Is there an easy way to call
functions that uses std::string or std:wstring in the function call ?

Has someone a tiny example how to access such a DLL with an
IJW-Interface ?


Thanx in advance,

Howie

 

[Willy Denoyette [MVP]]

| Hallo NG,
|
| i can call functions from a native C++-dll wich uses "const char *" as
| stringtype via P/Invoke without problems. Is there an easy way to call
| functions that uses std::string or std:wstring in the function call ?
|

You can't pass such kind of objects using PInvoke. PInvoke only deals with C
style functions and argument types.
| Has someone a tiny example how to access such a DLL with an
| IJW-Interface ?
|

IJW is a MC/C++ term and has nothing to do with C#, the only way to interop
with C/C++ is through PInvoke.

Willy.

 

[Howie Meier]

On Fri, 3 Nov 2006 10:16:54 +0100, "Willy Denoyette [MVP]"

Thanks Willy

| Has someone a tiny example how to access such a DLL with an
| IJW-Interface ?
|

IJW is a MC/C++ term and has nothing to do with C#, the only way to interop
with C/C++ is through PInvoke.

You are wrong. It means "It Just Works" and is the way to make a C++
DLL with managed and unmanaged Code together. The C# will only need to
access the C++ managed level.

Howie

 

[Willy Denoyette [MVP]]

| On Fri, 3 Nov 2006 10:16:54 +0100, "Willy Denoyette [MVP]"
|
| Thanks Willy
|
| >| Has someone a tiny example how to access such a DLL with an
| >| IJW-Interface ?
| >|
| >
| >IJW is a MC/C++ term and has nothing to do with C#, the only way to
interop
| >with C/C++ is through PInvoke.
| >
| You are wrong. It means "It Just Works" and is the way to make a C++
| DLL with managed and unmanaged Code together. The C# will only need to
| access the C++ managed level.


Sorry, but I'm right, C# doesn't have a notion of IJW, it's an "interop
layer" provided by the MC++ compiler to mixed mode C++ (/clr compiler flag)
it's not applicable to C# nor is it part of the CLR. Sure you can access
managed C++ from C#, both use the same object model, but you can't use C# to
access unmanaged C++ in a IJW fashion like MC++ is doing. Note also that the
term IJW is no longer used for C++/CLI, now it's called "C++ interop".

Willy.

 

[Howie Meier]

Sorry, but I'm right, C# doesn't have a notion of IJW, it's an "interop
layer" provided by the MC++ compiler to mixed mode C++ (/clr compiler flag)
it's not applicable to C# nor is it part of the CLR. Sure you can access
managed C++ from C#, both use the same object model, but you can't use C# to
access unmanaged C++ in a IJW fashion like MC++ is doing. Note also that the
term IJW is no longer used for C++/CLI, now it's called "C++ interop".

Excuse me Willy, you are right, i have read MFC not MC.

Thanks.

Howie