将字节数组从c ++传递到ac＃汇编有哪些不同的方法？

Question

I would like to know the different approaches that can be used to pass a byte array from c++ to c# and their performance characteristics. I would ideally like to pass a pointer to a byte array in an unmanaged heap to the C# assembly and avoid any copy operation.

Answer 1

Assuming that you're calling a C# method from unmanaged C++ using something like Reverse P/Invoke , you can just pass the pointer. The C# code should accept the pointer as IntPtr or UIntPtr , which it can then treat as an unmanaged array.

There are a number of ways to access the data behind that pointer once you pass it to the C# code. You can use Unsafe Code and Pointers , which is probably the highest performance if you're partying on individual bytes.

If you want to treat it as a stream of bytes, you could use UnmanagedMemoryStream .

Or, you can use the Marshal.Copy and Marshal.Read (many variants) methods to read different data types at different areas within that buffer.

None of the above require any copying of data other than the pointer itself between the C++ and C# code.

There are undoubtedly other ways to access the memory from C# that I haven't listed above. The gist of it is that passing an array of bytes either way is pretty painless.

Answer 2

I think you can have pointers on C++ side and ref on the C# side. Refer the link provided in the comment.