Instead of all groups you crossposted to, you had better posted
post this to (Compaq)Intel Fortran Developer Forum at

http://intel.forums.liveworld.com/forum.jsp?forum=76

OK, since I grumbled about the crosspost (few irrelevant
groups snipped), let me try to answer:

[quoted text, click to view]
| My C# program need a string returned from a Fortran Dll.
| The Fortran Dll is like this:
|
| SUBROUTINE REDO(s)

That compiles?
Shouldn't that be !DEC$ ATTRIBUTES C, DLLEXPORT::REDO instead?

| !DEC$ ATTRIBUTES DLLEXPORT::REDO, C

| CHARACTER*(*) s
| !DEC$ ATTRIBUTES REFERENCE :: s
| s = 'Let them talk, now!'C
| END

I'm not familiar with C#, but with the change above, the code will
be equivalent (interchangeable with) to:

extern "C" void __cdecl redo(char* s)
{
strcpy(s, "Let them talk, now!");
}

--
Jugoslav
___________
www.geocities.com/jdujic

Dear all:
My C# program need a string returned from a Fortran Dll.
The Fortran Dll is like this:

SUBROUTINE REDO(s)
!DEC$ ATTRIBUTES DLLEXPORT::REDO, C
CHARACTER*(*) s
!DEC$ ATTRIBUTES REFERENCE :: s
s = 'Let them talk, now!'C
END

And I use C# PInvoke to call it, the client code like this:

public class BackString
{
[DllImport(@"BackString.dll",
EntryPoint="REDO")]
public static extern void REDO(string output);
}

string output = "";
BackString.REDO(output);

When I call this, I got an NullReferenceException, can anybody here explain
why? and how could I return the string?

I also tried to return the value as "Return" but have the same problem. The
..NET Framework's PInvoke example to use C's return string works fine, but I
just can't make the Fortran work.

Thank everybody and hope I could get some reply.

Regards
Alex

Hi,

[quoted text, click to view]

StringBuilder should be used for string out arguments. How about the
following in C# ?

public static extern void REDO(StringBuilder output);

.....

StringBuilder sb = new StringBuilder(1024);
REDO(sb);
Console.WriteLine(sb);


...
Regards,
Vadim

What about

string output = new String( new char[ 256 ]);

Hope this helps.

Regards,
Xin

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