Question

I’m having a real strange issue while working with streams in mono.
I open a stream like this:

_stream = new FileStream(filename, FileMode.Open, FileAccess.ReadWrite, FileShare.Read);

Where _stream of course is a FileStream. I added a dispose method for this class like that:

public override void Dispose()
{
    Dispose(true);
    GC.SuppressFinalize(this);
}

private void Dispose(bool disposing)
{
    if(!_disposed)
    {
        if(disposing)
        {
            _stream.Flush(true);
            _stream.Dispose();
            _items.Clear();
        }
        _disposed = true;
    }
}

Now i have this simple test:

[Test]
public void SimpleTest()
{
    SyncFileWriter s = new SyncFileWriter("file");
    s.Save("a", "b");
    s.Dispose();

    SyncFileWriter s2 = new SyncFileWriter("file");
    s2.Dispose();
}

But if fails with a IOException: Sharing violation. [edit]It looks like there was an error with monodevelop. Restarted it and now it fails everytime[/edit]

How to avoid this and close the stream properly?

Answer 1

It looks like it was my fault. The SyncFileWriter is derived from a abstract class that checkes whether the file exist, or not. If not, it will initialize this file with some default things and that’s why I did the following

File.Create(filename);

As you see, I create a file, but File.Create opens a stream and does not close it after leaving it’s scope, whatever.
Now I do this:

Filestream f = File.Create(filename);
...
f.Dispose();

and everything is fine.

I think here lies also the problem for the first nondeterministic behavoir, because it does this only, when a parameter is null, and it is only null, when you create a new file.

Anyway, Thanks for your help!