Re: Why is a "char *" method parameter being projected as a "sbyte *"?

[Ben Voigt [C++ MVP]]

Chip Gore wrote:

On Apr 10, 4:54 pm, "Peter Duniho" <[e-mail]>
wrote:

>On Thu, 10 Apr 2008 14:41:19 -0700, Chip Gore
<[e-mail]:

>>[...]
And when I try and call this from "C-Sharp-Land", I'm being told
that my s1 and s2 are of type "sbyte *", and I'm not sure how to
get a C# "string" to be able to be passed in to my DEMO::DoStuff()
method.

Short, useless answer: in C#, the "char" type is Unicode, 2 bytes per
character. A C++ "char" is in fact the same as a C# "sbyte" (signed
byte).

What you really want to know is how to get .NET strings to play nice
with C++ strings ("char" arrays). Depending on what your C++ code
is doing, you either need to just use .NET strings (i.e. instances
of "String") in your managed C++ code, or you need to marshal
between the .NET String class and your C++ strings. Here's an MSDN
page that might be a good starting
point:http://msdn2.microsoft.com/en-us/library/bb384865.aspx

In this newsgroup, Ben, Willy, and maybe one or two others, might
have an answer to your question. But this is a perfect example of
the sort of question that is completely on-topic in the
microsoft.public.dotnet.framework.interop newsgroup. In that forum,
they are doing this sort of thing on a regular basis and you'll get
the best, most complete answers posting in that newsgroup.

Pete

Thanks for the feedback, I'll re-post the request in the interop
newsgroup

Actually, because you are using the C++/CLI compiler,
microsoft.public.dotnet.languages.vc is the most appropriate place to
discuss this.

To be useful from C# and other .NET languages, the member functions of your
ref class should accept parameters of type System::String^. The C++/CLI
compiler provides some pretty simple methods for getting the data as native
C++ characters if you need to, for example the PtrToStringChars function.