Using a DLL function in C# that requires a pointer as argument, am I declaring this properly?

Question

I am developing an application with C# and have to call an external function from a DLL. This function requires a pointer to an integer array as an argument. The DLL documentation states that the integer array must have >= 4kb space allocation. I know C# steers away from pointers but I'm pretty sure I don't have a choice here, no? How do I allocate a pointer to an integer array and guarantee it is >= 4kb in size, in C#?

I have:

public readonly unsafe int*[] dataBuffer = new int*[1000];

But I am not sure if this is correct.

Method signature is

int DataRec(void* buf);

Answer 1

This is a quite simple case, you just need a pointer to an array, not an array of pointers (as you have declared).

This should work:

byte[] buf = new byte[4096]; // allocate managed buffer
fixed (int* p = &buf[0]) // create a fixed pointer to the first element of the buffer (= to the buffer itself)
{ 
   int result = DataRec(p);
   // ...
   // use the data
}