How can I pin an array of byte?

Question

I want to pin an array of bytes which is 10 megabytes long so that managed and unmanaged code can work on it.

My scenario is that I have an unmanaged driver which reads some data from the device and writes it to the big array and the managed application just reads that data.

Something like this:

byte[] dataArray = new byte[10*1024*1024]; 

I want to pin dataArray so that GC does not move it.

What happens actually when I just run the application, I get a DataAbortApplication, and after reading on the internet I found out that I should pin the dataArray to avoid this error.

How/what should I do?

Answer 1

There are 2 ways to do this. The first is to use the fixed statement:

unsafe void UsingFixed() {     var dataArray = new byte[10*1024*1024];     fixed (byte* array = dataArray)     {         // array is pinned until the end of the 'fixed' block     } } 

However, it sounds like you want the array pinned for a longer period of time. You can use GCHandles to accomplish this:

void UsingGCHandles() {     var dataArray = new byte[10*1024*1024];     var handle = GCHandle.Alloc(dataArray, GCHandleType.Pinned);      // retrieve a raw pointer to pass to the native code:     IntPtr ptr = handle.ToIntPtr();      // later, possibly in some other method:     handle.Free(); }