Generics in C#

[ayufan]

Hello,

I have been trying to write code with generics. But following syntax is bad,
in my opinion it shouldn't be.

--- CODE ---
public unsafe void Test2(void* data)
{
....
}

public unsafe void Test<T>(T value) where T : struct
{
Test2((void*)&v alue);
}
--- END CODE ---

Compiler says that "Cannot take the address of, get the size of, or declare
a pointer to a managed type ('T')"
but T is value type...
Is there any other solution's?
Sorry about my english...

Thanks.

[Mattias Sjögren]

Re: Generics in C#

[color=blue]
>but T is value type...[/color]

You can't use all value type in unsafe code. And since the compiler
can't be sure you're only using types that are "compatible " with
unsafe code, code like that is not allowed.

[color=blue]
>Is there any other solution's?[/color]

Unfortunately not.



Mattias

--
Mattias Sjögren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.

[Dodo Cibelli]

Re: Generics in C#


I thick this is a solution

GCHandle dataHandle = GCHandle.Alloc( Data, GCHandleType.Pi nned);
public void* pData = (void*) dataHandle.Addr OfPinnedObject( );

as in the following class.

Unfortunatey you can't do this

public S* pData;
pData = ( S*) dataHandle.Addr OfPinnedObject( );

Just the declare gives a compiling error
Does anyone know how to cast a pointer to a generic type?


this works

unsafe public class PinnedClass<S> where S : new()
{
public S Data;
public void* pData;
private GCHandle dataHandle;

public PinnedClass()
{
Data = new S();
dataHandle = GCHandle.Alloc( Data, GCHandleType.Pi nned);
pData = (void*) dataHandle.Addr OfPinnedObject( );
}

public void Pin()
{
UnPin();
dataHandle = GCHandle.Alloc( Data, GCHandleType.Pi nned);
pData = (void*)dataHand le.AddrOfPinned Object();
}

public void UnPin()
{
if (pData != null)
{
dataHandle.Free ();
pData = null;
}
}


}

this is what I'd like but does not compile

unsafe public class PinnedClass<S> where S : new()
{
public S Data;
public S* pData;
private GCHandle dataHandle;

public PinnedClass()
{
Data = new S();
dataHandle = GCHandle.Alloc( Data, GCHandleType.Pi nned);
pData = (S*) dataHandle.Addr OfPinnedObject( );
}

public void Pin()
{
UnPin();
dataHandle = GCHandle.Alloc( Data, GCHandleType.Pi nned);
pData = (S*)dataHandle. AddrOfPinnedObj ect();
}

public void UnPin()
{
if (pData != null)
{
dataHandle.Free ();
pData = null;
}
}


}




"Mattias Sjögren" wrote:
[color=blue]
>[color=green]
> >but T is value type...[/color]
>
> You can't use all value type in unsafe code. And since the compiler
> can't be sure you're only using types that are "compatible " with
> unsafe code, code like that is not allowed.
>
>[color=green]
> >Is there any other solution's?[/color]
>
> Unfortunately not.
>
>
>
> Mattias
>
> --
> Mattias Sjögren [MVP] mattias @ mvps.org
> http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
> Please reply only to the newsgroup.
>[/color]