Does FileStream(SafeFileHandle) have a independent Position (with .NET 6)

[msedi]

Originally since the FileStream was working with Set/GetFilePointer the problem was that the use of a FileStream allocated with

FileStream originalStream;
FileStream newStream = new FileStream(originalStream.SafeFileHandle, FileAccess.Read);

was not threadsafe. Since you changed that FileStream has now its internal FilePointer without accessing the Set/GetFilterPointer it seems to me that this is threadsafe now, but couldn't find any note on this. Can someone please clarify?

[stephentoub]

A FileStream instance should not be used concurrently. If you need concurrent access, you can use the RandomAccess type introduced in .NET 6.

[msedi]

@stephentoub. Thx. I understand that the instance itself is not threadsafe. But originally (before the .NET 6 changes on the filestream) the problem was that even when creating two instances like above where I used originalStream in Thread 1 and newStream in Thread 2 the file pointer was shared. Is this something that shouldn't be done in general, if yes is then the use of the constructor only to hand over a handle created by CreateFile?

[msedi]

@stephentoub: Do you have a hint for me in this case. I'm not sure if I can use it as needed or if it currently simply works but crashes on some unknown condition?