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Set C Function Pointer to C # Function

I need to set the callback function in the C library to be equal to the C # function, and cannot find a way to do this without using dlopen or kernel32, which apparently applies to / unix windows. Does anyone know a way to do this?

Problem: Pointers to functions are set in the C shared library whose values ​​must be specified by overwriting them. For example.

//C Code
extern void (*ptr_R_ShowMessage) (const char *)

The current C # code creates a delegate to the function that matches this signature, uses the marshal class to get a pointer to that delegate, and then overwrites the C pointer with this value.

//call to libdl or kernel32.dll 
IntPtr showPointer = GetFunctionAddress(hndl,"ptr_R_ShowMessage");
IntPtr newShowPointer = Marshal.GetFunctionPointerForDelegate(matchingDelegate);
Marshal.WriteIntPtr(showPointer, newShowPointer);

The requirement for libdl and kernel32.dll causes all kinds of problems ... and ideally could be avoided.

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void DecCallBack(int nPort, void* pBuf, int nSize, FRAME_INFO *pInfo, int nReserved1, int reserved 2);

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[UnmanagedFunctionPointer(CallingConvention.StdCall)]
delegate void DecCallBack(int nPort, IntPtr pBuf, int nSize, ref FRAME_INFO frameInfo, int nReserved1, int nReserved2);

DecCallBack, .

static DecCallBack _decodeCallBack = null;

, . HandleDecData()

private static void HandleDecData(int nPort, IntPtr pBuf, int nSize, ref FRAME_INFO frameInfo, int nReserved1, int nReserved2) {

   // Here we handle the callback,  this code is being called from an external C library

}

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_decodeCallBack += new DecCallBack(HandleDecData);

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 if( !PlayM4_SetDecCallBack(channel, _decodeCallBack) ) 
  throw new InvalidOperationException("Error setting DecCallBack");

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, , # : http://tutorials.csharp-online.net/CSharp_Delegates_and_Events%E2%80%94Win32_callbacks

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