On Mar 23, 3:24 pm, "gernot" <gernot...@gmail.com> wrote:
> Hi,
>
> I want to marshal the following C++ struct to a managed callback
> function:
>
> struct CALLBACK_DATA
> {
> LPBYTE pArray; // byte array
> UINT uArrayLen; // byte count
>
> };
>
> The C++ function expects the following callback type:
>
> typedef BOOL (CALLBACK *CALLBACK_FUNC)(const CALLBACK_DATA *pData,
> LPVOID pvParam);
>
> In C# first I import the C++ function:
>
> [DllImport("unmanaged.dll", EntryPoint = "Func")]
> static extern bool Func(CallbackFunc callback, IntPtr param);
>
> Where CallbackFunc is declared as a delegate:
>
> public delegate bool CallbackFunc(CallbackData data, IntPtr param);
>
> Then I define the callback and do the call:
>
> // the callback function
> public static bool Callback(CallbackData data, IntPtr param)
> {
>
> }
>
> CallbackFunc callback = new CallbackFunc(Callback);
> Func(callback, param);
>
> The question is how do I have to declare CallbackData?
>
> [StructLayout(LayoutKind.Sequential)]
> public class CallbackData
> {
> [MarshalAs(UnmanagedType.ByValArray, SizeConst=100)] // error!
> byte[] array;
> uint arrayLen;
>
> }
>
> I cannot find attibutes that fit for this situation.
> Anyway the array is not const size!
>
> Can anybody help?
>
> Thanks,
> Gernot

On Mar 25, 3:17 pm, meh...@hotmail.com wrote:
> On Mar 23, 3:24 pm, "gernot" <gernot...@gmail.com> wrote:
>
>
>
>
>
> > Hi,
>
> > I want to marshal the following C++ struct to a managed callback
> > function:
>
> > struct CALLBACK_DATA
> > {
> > LPBYTE pArray; // byte array
> > UINT uArrayLen; // byte count
>
> > };
>
> > The C++ function expects the following callback type:
>
> > typedef BOOL (CALLBACK *CALLBACK_FUNC)(const CALLBACK_DATA *pData,
> > LPVOID pvParam);
>
> > In C# first I import the C++ function:
>
> > [DllImport("unmanaged.dll", EntryPoint = "Func")]
> > static extern bool Func(CallbackFunc callback, IntPtr param);
>
> > Where CallbackFunc is declared as a delegate:
>
> > public delegate bool CallbackFunc(CallbackData data, IntPtr param);
>
> > Then I define the callback and do the call:
>
> > // the callback function
> > public static bool Callback(CallbackData data, IntPtr param)
> > {
>
> > }
>
> > CallbackFunc callback = new CallbackFunc(Callback);
> > Func(callback, param);
>
> > The question is how do I have to declare CallbackData?
>
> > [StructLayout(LayoutKind.Sequential)]
> > public class CallbackData
> > {
> > [MarshalAs(UnmanagedType.ByValArray, SizeConst=100)] // error!
> > byte[] array;
> > uint arrayLen;
>
> > }
>
> > I cannot find attibutes that fit for this situation.
> > Anyway the array is not const size!
>
> > Can anybody help?
>
> > Thanks,
> > Gernot
>
> Declare the array parameter as IntPtr,
> [StructLayout(LayoutKind.Sequential)]
> public class CallbackData
> {
> IntPtr array;
> uint arrayLen;
>
> }
>
> Then use Marshal class to handle the array.
>
> Hope this helps
> MH- Hide quoted text -
>
> - Show quoted text -