[英]Passing C# function pointers into C++/CLI interop dll
我正在嘗試將一個函數指針從C#傳遞到C ++ / CLI並得到一個Windows編譯器錯誤,指出該語言不支持ManagedTakeCallback
函數(C#) - 我在C ++ / CLI互操作中定義了ManagedTakeCallback
。 我的代碼看起來像
C#應用程序:
namespace ManagedConsoleApplication
{
class Callback
{
public delegate double DelegateAdd(double value1, double value2);
public static double CallbackAdd(double value1, double value2)
{
return value1 + value2;
}
public static DelegateAdd delegateCallback = new DelegateAdd(Callback.CallbackAdd); //declare as static to prevent GC
}
class Program
{
// [DllImport("InteropDLL.dll", CallingConvention = CallingConvention.StdCall)]
// public static extern void ManagedCallback(IntPtr pCallback);
static void Main(string[] args)
{
InteropDLL io = new InteropDLL();
Console.WriteLine("The Add return = {0}", io.ManagedAdd(3, 2));
Console.WriteLine("Pass CallBack to Unmanaged code");
Callback cb = new Callback();
IntPtr intptr_delegate = Marshal.GetFunctionPointerForDelegate(Callback.delegateCallback); //convert delegate to function pointer which can be used by unmanaged code
Console.WriteLine("The callback return is {0}", io.ManagedTakeCallback(intptr_delegate));
Console.WriteLine("Please hit Enter to exit");
String value = Console.In.ReadLine();
//Console.WriteLine("End of program ", value);
}
}
}
和,
C ++ / CLI interop dll h和cpp文件:
//HEADER
namespace Interop
{
typedef double (__stdcall *PCallback)(double value1, double value2);
public ref class InteropDLL
{
public:
double ManagedAdd(double value1, double value2);
public:
double ManagedTakeCallback(PCallback pCallback);
};
}
//CPP
double Interop::InteropDLL::ManagedAdd(double value1, double value2)
{
return NativeAdd(value1, value2);
}
double Interop::InteropDLL::ManagedTakeCallback(PCallback pCallback)
{
return NativeTakeCallback();
}
然后,C ++ / CLI互操作層調用C DLL。 我可以調用ManagedAdd
互操作函數; 但是,如果添加了ManagedTakeCallback
,則會出現Windows編譯器錯誤。 我懷疑C#應用程序沒有通過ManagedTakeCallback
函數正確編組函數指針,或者C ++ / CLI端的簽名不正確? 我非常感謝任何見解。
以下是現場評論:
“但是C#不支持C ++函數指針,所以我們不能在這里調用C ++函數指針.C#只有Delegate對象,我們必須通過Marshal.GetDelegateForFunctionPointer將函數指針轉換為Delegate。它在System.Runtime.InteropServices中聲明如下:
public static Delegate GetDelegateForFunctionPointer ( IntPtr ptr, Type t)
如需完整答案,請查看鏈接: http : //www.codeproject.com/Articles/27298/Dynamic-Invoke-C-DLL-function-in-C
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