Returning long pointer value from unmanaged DLL entry point

Question

I have one entry point in my unmanaged DLL and this is the code from its C code

void *__cdecl entryp(int a1, int a2, __int64 a3, signed int a4, int a5)
{
  void *v6; 
  /..../
  /..../

  return v6;
}

and i use dllimport on my C# project with this

[DllImport("unmanaged.dll", EntryPoint = "entryp",CallingConvention = CallingConvention.Cdecl)]
public static extern unsafe long* entryp(byte[] bData, uint length, ushort width, ushort heigth, uint nMaxCode, short anaLevel);

but the problem is the method just does not return anything whats going wrong with my code? Thanks for reading my question

Answer 1

The code in the DLL must be exported, so I'd expect the declaration to be:

void* __declspec(dllexport) entryp(int a1, int a2, __int64 a3, signed int a4, int a5)
{
  //...
}