Steve Richter wrote:

> Cannot marshal 'parameter #7': Pointers cannot reference marshaled
> structures. Use ByRef instead.

On Mar 5, 5:30 pm, Tamas Demjen <tdem...@yahoo.com> wrote:
> Steve Richter wrote:
> > Cannot marshal 'parameter #7': Pointers cannot reference marshaled
> > structures. Use ByRef instead.
>
> You must have a name collision. You're probably not calling the
> unmanaged Win32 FormatMessage, but another function that happens to have
> the same name.
>
> Your code compiles for me without any errors (VC++2005 SP1). Just try to
> put it into an empty unit, like this:
>
> // FormatMessage.cpp
> #include "stdafx.h"
> #include <windows.h>
>
> using namespace System;
>
> String^ FormatMessage( DWORD rc )
> <snip> // your code unchanged
>
> If that still doesn't work, remove #include "stdafx.h" and disable
> precompiled headers for that unit.
>
> Tom

"Steve Richter" <StephenRichter@gmail.com> wrote in message
news:1173155219.298389.112910@8g2000cwh.googlegroups.com...
> On Mar 5, 5:30 pm, Tamas Demjen <tdem...@yahoo.com> wrote:
>> Steve Richter wrote:
>> > Cannot marshal 'parameter #7': Pointers cannot reference marshaled
>> > structures. Use ByRef instead.
>>
>> You must have a name collision. You're probably not calling the
>> unmanaged Win32 FormatMessage, but another function that happens to have
>> the same name.
>>
>> Your code compiles for me without any errors (VC++2005 SP1). Just try to
>> put it into an empty unit, like this:
>>
>> // FormatMessage.cpp
>> #include "stdafx.h"
>> #include <windows.h>
>>
>> using namespace System;
>>
>> String^ FormatMessage( DWORD rc )
>> <snip> // your code unchanged
>>
>> If that still doesn't work, remove #include "stdafx.h" and disable
>> precompiled headers for that unit.
>>
>> Tom
>
> thanks for the help. The solution ended up being a change in the
> project from "pure MSIL CLR support" to what I guess is a more
> flexible "clr support".
>
> now I am reading in the archives that I cant call my C++ code from C#
> unless the c++ is pure MSIL? The FormatMessage API bombed on the last

> argument, a VARARG or whatever it is called. How do I know what
> unmanaged code can be included in a "pure MSIL" project and what cant?

>
> -Steve
>
>

>In the case of FormatMessage, it's not that MSIL can't make the call, it's
>that the compiler hasn't enough information to construct the P/Invoke
>signature. However, you could do that yourself, just as doing P/Invoke from
>C# (http://www.pinvoke.net/default.aspx/kernel32/FormatMessage.html)