Bug 23724 - BeginReceive receives null bytes.
Summary: BeginReceive receives null bytes.
Status: NEW
Alias: None
Product: Class Libraries
Classification: Mono
Component: System (show other bugs)
Version: 3.8.0
Hardware: Macintosh Mac OS
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2014-10-09 16:23 UTC by Alberto Simoes
Modified: 2014-12-28 20:33 UTC (History)
2 users (show)

See Also:
Is this bug a regression?: ---
Last known good build:


Description Alberto Simoes 2014-10-09 16:23:13 UTC

I have a server like this:

    public void Run() {
        while (true) {
            if (curThreads < maxThreads) {
                AsyncCallback callback = new AsyncCallback (ProcessRequest);
                client.BeginReceive (callback, this);

and the callback is

    public static void ProcessRequest(IAsyncResult result) {
        LogSink lg = result.AsyncState as LogSink;

        IPEndPoint endPoint = new IPEndPoint (IPAddress.Any, 0);
        byte[] message = lg.client.EndReceive (result, ref endPoint);

        String str = Encoding.ASCII.GetString (message, 0, message.Length);


Now, if I limit everything to 1 thread, it works perfectly well... the string I am sending is received correctly. If I use a limit of 10 threads (10 async receives) , then I receive a byte array of null values. The size of the buffer is the correct (the size of the string I am sending), but all characters are null.

Curiously, this is the behavior with MONO in Mac OS X. 
This code works correctly for Windows machines with Visual Studio.

Thank you for any insight.
Comment 1 mangine 2014-12-28 20:33:37 UTC
Simple application with EndReceive doesn't work on Windows:

        private void ReadCallback(IAsyncResult result)
            IPEndPoint server = new IPEndPoint(IPAddress.Any, 0);

            //newData receives null bytes only
            byte[] newData = client.EndReceive(result, ref server);

            int _readBytes = newData.Length;



        public void Read()
            if (!isOpen) return;
            client.BeginReceive(ReadCallback, null);

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