hello,
I have to load an unmanaged dll written in Delphi to my C# 2.0 application.
The unmanaged function has one parameter; pointer to an interface and return this pointer.
I am not sure how to declare the delegate and to use it.
My code below;
//here unsure about the signature
internal delegate MyDel (out IntPtr IModule);
IntPtr
hModule = LoadLibrary("mydll.dll"); //if the handle is valid try to call members if (hModule != IntPtr.Zero){
//get the function pointer IntPtr fptr = GetProcAddress(hModule, "GetInterface"); if (fptr != IntPtr.Zero){
MyDel mgi = (MyDel)Marshal.GetDelegateForFunctionPointer(fptr, typeof(MyDel)); //here unsure IntPtr ptrModuleInterface;mgi(
out ptrModuleInterface);}
else Marshal.GetHRForLastWin32Error();FreeLibrary(hModule;
}
else Marshal.GetHRForLastWin32Error();Could you please help me to figure this out
Thanks,
Ada
Interop problem (.NET 2.0 )
Adah
safecall is just a calling convention that means any [out,retval] parameters become function results. I cant see that being a problem. I am out of ideas.. can you provide a crash dump (use AdPlus, Debugging tools for windows, http://www.microsoft.com/whdc)
Solero
Your delegate signature should match whatever the GetInterface signature is.
public delegate void GetInterfaceDelegate(out IntPtr someptr);
Todd-TSIC
thats because the myModuleDelg() delegate is returning an IntPtr. You need to marshal the IntPtr to the IInterface.
If the Interface implements IUnknown you can use Marshal.GetObjectForIUnknown.
eg IInterface _interface = (IInterface)Marshal.GetObjectForIUnknown(myModuleDelg());
else use the Marshal.PtrToStructure method.
eg. IInterface _interface = (IInterface)Marshal.PtrToStructure(myModuleDelg(),typeof(IInterface));
thrakazog
Hi,
Thanks Nikhil, now I understand better how the Marshalling of IntPtr works ,but I still get the same error.
Maybe the problem resides on the Delphi dll side. The unmanged function is marked "safe call":
function GetInterface: IInterface2; safe call;.
IInterface2 is derived from IInterface.
Any ideas
Thanks,
Ada
ammukarthik
Hi,
Thank you Nikhil, but my problem is a bit more complex, please see below:
I have two cases:
When the unmanaged function looks like:
1. function GetInterface (out IInterface); works fine
2. function GetInterface: IInterface; - got an error
here is the code:
//my delegate:
public delegate IntPtr GetInterfaceDelegate();
//get the handle to the module
IntPtr handle = LoadLibrary("MyDLL.dll"); //get the function pointer IntPtr fptr = GetProcAddress(hCardio, "GetInterface"); //gets the delegate for fptr GetInterfaceDelegate myModuleDelg = (GetInterfaceDelegate)Marshal.GetDelegateForFunctionPointer(fptr, typeof(GetInterfaceDelegate)); IInterface iInterface; iInterface = myModuleDelg();I have got this error;
"Message: Attempted to read or write protected memory. This is often an indication that other memory is corrupt"
Thanks,
Ada