How can I pass a pointer to an array using p/invoke in C#?

Question

Example C API signature:

void Func(unsigned char* bytes);

In C, when I want to pass a pointer to an array, I can do:

unsigned ch         


        

Answer 1

You can use unsafe code:

unsafe 
{
     fixed(byte* pByte = byteArray)
     IntPtr intPtr = new IntPtr((void *) pByte);
     Func(intPtr);
}

If you need to use safe code, you can use a few tricks:

IntPtr intPtr = Marshal.AllocHGlobal(Marshal.SizeOf(byteArray));
Marshal.Copy(byteArray, 0, intPtr, Marshal.SizeOf(byteArray));

Func(intPtr);

Marshal.FreeHGlobal(intPtr);

However, the safe code is going to be slow IMHO.