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  • WPF 3D - converting from Point2D to Point3D and back again

    - by DanM
    I'm new to WPF 3D, so I may just be missing something obvious, but how would I go about converting from a 2D coordinate to a 3D coordinate and back again? I'd like the 2D coordinate to be the location measured from the upper-left corner of Viewport3D and the 3D coordinate to be the location relative to the origin (0, 0, 0) of the 3D world. The conversion functions should have these signatures: public Point3D Point2DAndWorldZToPoint3D(Point2D point2D, double worldZ) // usually I want to know where a 2D point will be on the ground plane // so worldZ will usually be zero (but not always) public Point2D Point3DToPoint2D(Point3D point3D) I found this related question, but it only addresses conversion from 3D to 2D (not the reverse), and I'm not sure if the answers are up-to-date. Note, I'm currently using .NET 3.5, but if there are improvements in .NET 4.0 that would help me, please let me know.

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  • TFS Changeset history using QueryHistory after branch rename

    - by bryantb
    I'm using the VersionControlServer.QueryHistory method to retrieve a list of files that have changed during a timespan that ranges from 5/1/2009 to 10/1/2009. My results unexpectedly only included items that had changed after 9/1/2009. I then realized that the path that I was using, $/Project/Reports/Main, didn't exist until 9/1/2009. Before 9/1/2009, there had been another node named $/Project/Main/Reports, which was renamed to $/Project/Reports/Main. When I query from Source Control Explorer I can see the entire history (5/1/2009 - 10/1/2009) that I expect to see. However, I can't get the same results via the API. I've tried to specify the branch that no longer exists because it was renamed, but not surprisingly I get zero results. Any ideas?

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  • com.jcraft.jsch.JSchException: UnknownHostKey

    - by Alex
    I don't know how SSH works and I think that's a simple question. How do I fix that exception: com.jcraft.jsch.JSchException: UnknownHostKey: mywebsite.com. RSA key fingerprint is 22:fb:ee:fe:18:cd:aa:9a:9c:78:89:9f:b4:78:75:b4 I know I should verify that key or something, but there is like zero documentation for Jsch. Here is my code it's really straightforward: import com.jcraft.jsch.JSch; import com.jcraft.jsch.Session; public class ssh{ public static void main(String[] arg){ try{ JSch jsch = new JSch(); //create SSH connection String host = "mywebsite.com"; String user = "username"; String password = "123456"; Session session = jsch.getSession(user, host, 22); session.setPassword(password); session.connect(); } catch(Exception e){ System.out.println(e); } } }

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  • Specified key is not a valid size for this algorithm...

    - by phenevo
    Hi, I have with this code: RijndaelManaged rijndaelCipher = new RijndaelManaged(); // Set key and IV rijndaelCipher.Key = Convert.FromBase64String("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz012345678912"); rijndaelCipher.IV = Convert.FromBase64String("1234567890123456789012345678901234567890123456789012345678901234"); I get throws : Specified key is not a valid size for this algorithm. Specified initialization vector (IV) does not match the block size for this algorithm. What's wrong with this strings ? Can I count at some examples strings from You ?

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  • Add onblur event to ASP.Net MVC's Html.TextBox

    - by justSteve
    What's the correct syntax for an HTML helper (in MVC2) to define an onblur handler where the textbox is generated with code like: <%=Html.TextBox( "ChooseOptions.AddCount" + order.ID, (order.Count > 0) ? AddCount.ToString() : "", new { @class = "{number: true} small-input" } ) thx

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  • Is there a good way to convert between BitmapSource and Bitmap?

    - by JohannesH
    As far as I can tell the only way to convert from BitmapSource to Bitmap is through unsafe code... Like this (from Lesters WPF blog): myBitmapSource.CopyPixels(bits, stride, 0); unsafe { fixed (byte* pBits = bits) { IntPtr ptr = new IntPtr(pBits); System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap( width, height, stride, System.Drawing.Imaging.PixelFormat.Format32bppPArgb,ptr); return bitmap; } } To do the reverse: System.Windows.Media.Imaging.BitmapSource bitmapSource = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap( bitmap.GetHbitmap(), IntPtr.Zero, Int32Rect.Empty, System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions()); Is there an easier way in the framework? And what is the reason it isn't in there (if it's not)? I would think it's fairly usable. The reason I need it is because I use AForge to do certain image operations in an WPF app. WPF wants to show BitmapSource/ImageSource but AForge works on Bitmaps.

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  • msdeploy IIS 6 to 7 migration issue

    - by rboorgapally
    I am trying to view the dependencies of my website on IIS 6.0 running on windows server 2003. When I type the following command, msdeploy -verb:getDependencies -source:metakey=lm/w3svc/1 I got the following error: C:\Program Files\IIS\Microsoft Web Deploy>msdeploy -verb:getDependencies -source :metakey=lm/w3svc/1 Error: Object of type 'metaKey' and path 'lm/w3svc/1' cannot be created Error: The metabase key '/lm/w3svc/1' could not be found. Error: Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED)) Error count: 1 Can any one explain these to me?

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  • DataBinding: 'System.String' does not contain a property with the name 'dbMake'.

    - by marcmiki
    Hi , i am a newbie at ASP.net and after using sqldatasource with a listview to insert and show results from an SQL server db i want to try using the LINQ datasource since it seems to be more flexible in codebehind. My problem is this: i droped a listview control to the page and i created the Linq datasource in codebehind with vb. the issue that i am having when i ..Select d.columms name i get the error system.string does not contain a property with the name "columname".. if i ommit the column name then its works fine.. the funny part is the d.count works fine but after that i get the error.. please see my code below: vb code Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim rowsCount As Integer Dim showSearchForm As String showSearchForm = Request.QueryString("tab") If showSearchForm = "1" Then Dim db As New ASPNETDBDataContext() Dim q = From b In db.PassengerVehiclesTables Select b.dbMake rowsCount = q.Count MsgBox(rowsCount) lvMakes.DataSource = q lvMakes.DataBind() PnlPassengerVehiclesSearch.Visible = True ElseIf showSearchForm = "2" Then aspx code <asp:Panel ID="PnlPassengerVehiclesSearch" Visible="false" runat="server"> Search Passenger Vehicles Form.....<br /> <table style="width: 100%; border-style: solid; border-width: 1px"> <tr> <td> <asp:ListView ID="lvMakes" runat="server"> <LayoutTemplate> <asp:PlaceHolder runat="server" ID="itemPlaceholder" /> </LayoutTemplate> <ItemTemplate> <%#Eval("dbMake")%><br /> </ItemTemplate> </asp:ListView> </td> b.dbMake needs to work so that i can use Distinct ,, ia m using asp.net version:3.5 and IIS version 7.0 .. not sure what i am missing ,, but i did try alot of approaches,,1- checked the web.config file and it seems to have two assemblies and two namespaces for LINQ..2- used different databinding syntaxs,,and i searched a lot for the solution.. the last one i read the person ommited the name of the column,, i thought that wasnt the best solution.. also my dbMake column is comming up in the "intellisence" .. thank you in advance for your help..

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  • mouse_event WinAPI call not working when cursor is over Flash

    - by friederbluemle
    Hi, I am writing a small program which can simulate mouse clicks at specified positions. Using the Win32 API call mouse_event like so: [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)] public static extern void mouse_event(uint dwFlags, uint dx, uint dy, uint dwData, UIntPtr dwExtraInfo); [Flags] public enum MouseEventFlags : uint { LEFTDOWN = 0x00000002, LEFTUP = 0x00000004, MIDDLEDOWN = 0x00000020, MIDDLEUP = 0x00000040, MOVE = 0x00000001, ABSOLUTE = 0x00008000, RIGHTDOWN = 0x00000008, RIGHTUP = 0x00000010 } mouse_event((uint)(MouseEventFlags.LEFTDOWN | MouseEventFlags.LEFTUP), x, y, 0, UIntPtr.Zero); Works perfectly fine, except when the mouse cursor is over a Flash application. Flash seems to ignore the simulated mouse click. What could be the reason for this? And how do I fix it? Thank you!

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  • ASP.NET GridView second header row to span main header row

    - by Dana Robinson
    I have an ASP.NET GridView which has columns that look like this: | Foo | Bar | Total1 | Total2 | Total3 | Is it possible to create a header on two rows that looks like this? | | Totals | | Foo | Bar | 1 | 2 | 3 | The data in each row will remain unchanged as this is just to pretty up the header and decrease the horizontal space that the grid takes up. The entire GridView is sortable in case that matters. I don't intend for the added "Totals" spanning column to have any sort functionality. Edit: Based on one of the articles given below, I created a class which inherits from GridView and adds the second header row in. namespace CustomControls { public class TwoHeadedGridView : GridView { protected Table InnerTable { get { if (this.HasControls()) { return (Table)this.Controls[0]; } return null; } } protected override void OnDataBound(EventArgs e) { base.OnDataBound(e); this.CreateSecondHeader(); } private void CreateSecondHeader() { GridViewRow row = new GridViewRow(0, -1, DataControlRowType.Header, DataControlRowState.Normal); TableCell left = new TableHeaderCell(); left.ColumnSpan = 3; row.Cells.Add(left); TableCell totals = new TableHeaderCell(); totals.ColumnSpan = this.Columns.Count - 3; totals.Text = "Totals"; row.Cells.Add(totals); this.InnerTable.Rows.AddAt(0, row); } } } In case you are new to ASP.NET like I am, I should also point out that you need to: 1) Register your class by adding a line like this to your web form: <%@ Register TagPrefix="foo" NameSpace="CustomControls" Assembly="__code"%> 2) Change asp:GridView in your previous markup to foo:TwoHeadedGridView. Don't forget the closing tag. Another edit: You can also do this without creating a custom class. Simply add an event handler for the DataBound event of your grid like this: protected void gvOrganisms_DataBound(object sender, EventArgs e) { GridView grid = sender as GridView; if (grid != null) { GridViewRow row = new GridViewRow(0, -1, DataControlRowType.Header, DataControlRowState.Normal); TableCell left = new TableHeaderCell(); left.ColumnSpan = 3; row.Cells.Add(left); TableCell totals = new TableHeaderCell(); totals.ColumnSpan = grid.Columns.Count - 3; totals.Text = "Totals"; row.Cells.Add(totals); Table t = grid.Controls[0] as Table; if (t != null) { t.Rows.AddAt(0, row); } } } The advantage of the custom control is that you can see the extra header row on the design view of your web form. The event handler method is a bit simpler, though.

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  • Is there a way of recover from an Exception in Directory.EnumerateFiles ?

    - by Magnus Johansson
    In .NET 4, there's this Directory.EnumerateFiles() method with recursion that seems handy. However, if an Exception occurs within a recursion, how can I continue/recover from that and continuing enumerate the rest of the files? try { var files = from file in Directory.EnumerateFiles(@"c:\", "*.*", SearchOption.AllDirectories) select new { File = file }; Console.WriteLine(files.Count().ToString()); } catch (UnauthorizedAccessException uEx) { Console.WriteLine(uEx.Message); } catch (PathTooLongException ptlEx) { Console.WriteLine(ptlEx.Message); }

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  • Word Spell Check pops up hidden and "freezes" my App

    - by Refracted Paladin
    I am using Word's Spell Check in my in house WinForm app. My clients are all XP machines with Office 2007 and randomly the spell check suggestion box pops up behind the App and makes everything "appear" frozen as you cannot get at it. Suggestions? What do other people do to work around this or stop it altogether? Thanks Below is my code, for reference, though I am doubtful that this has anything to do with my code but I'll take anything. public class SpellCheckers { public string CheckSpelling(string text) { Word.Application app = new Word.Application(); object nullobj = Missing.Value; object template = Missing.Value; object newTemplate = Missing.Value; object documentType = Missing.Value; object visible = false; object optional = Missing.Value; object savechanges = false; app.ShowMe(); Word._Document doc = app.Documents.Add(ref template, ref newTemplate, ref documentType, ref visible); doc.Words.First.InsertBefore(text); Word.ProofreadingErrors errors = doc.SpellingErrors; var ecount = errors.Count; doc.CheckSpelling(ref optional, ref optional, ref optional, ref optional, ref optional, ref optional, ref optional, ref optional, ref optional, ref optional, ref optional, ref optional); object first = 0; object last = doc.Characters.Count - 1; var results = doc.Range(ref first, ref last).Text; doc.Close(ref savechanges, ref nullobj, ref nullobj); app.Quit(ref savechanges, ref nullobj, ref nullobj); Marshal.ReleaseComObject(doc); Marshal.ReleaseComObject(app); Marshal.ReleaseComObject(errors); return results; } } And I call it from my WinForm app like so -- public static void SpellCheckControl(Control control) { if (IsWord2007Available()) { if (control.HasChildren) { foreach (Control ctrl in control.Controls) { SpellCheckControl(ctrl); } } if (IsValidSpellCheckControl(control)) { if (control.Text != String.Empty) { control.BackColor = Color.FromArgb(180, 215, 195); control.Text = Spelling.CheckSpelling(control.Text); control.Text = control.Text.Replace("\r", "\r\n"); control.ResetBackColor(); } } } }

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  • .Net Intermittent System.Web.Services.Protocols.SoapHeaderException

    - by ScottE
    We have a .net 3.5 web app that consumes third party web services. The proxy was created by adding a web reference to their wsdl. This proxy is not compiled. Our error logging is picking up frequent but intermittent exceptions: An exception of type 'System.Web.Services.Protocols.SoapHeaderException' occurred and was caught If I follow the url to the page that generated the exception, I can't recreate it. Edit: Here is most of the exception - where it bubbled up from Message : Internal Error Type : System.Web.Services.Protocols.SoapHeaderException, System.Web.Services, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a Source : System.Web.Services Help link : Actor : Code : http://schemas.xmlsoap.org/soap/envelope/:Client Detail : Lang : Node : Role : SubCode : Data : System.Collections.ListDictionaryInternal TargetSite : System.Object[] ReadResponse(System.Web.Services.Protocols.SoapClientMessage, System.Net.WebResponse, System.IO.Stream, Boolean) Stack Trace : at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall) at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters) at Vendor.getSearch(getSearchRequest getSearchRequest) in c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\be43c34e\b09edc7e\App_WebReferences.pww-cf-q.0.cs:line 73 Edit 2: Inner exceptions: I sometimes get the following inner exceptions logged: Message : Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. Type : System.IO.IOException, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089 Source : System Help link : Data : System.Collections.ListDictionaryInternal TargetSite : Int32 Read(Byte[], Int32, Int32) Stack Trace : at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size) at System.Net.FixedSizeReader.ReadPacket(Byte[] buffer, Int32 offset, Int32 count) at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest) at System.Net.Security.SslState.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest) at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest) at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest) at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult) at System.Net.TlsStream.CallProcessAuthentication(Object state) at System.Threading.ExecutionContext.runTryCode(Object userData) at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData) at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Net.TlsStream.ProcessAuthentication(LazyAsyncResult result) at System.Net.TlsStream.Write(Byte[] buffer, Int32 offset, Int32 size) at System.Net.PooledStream.Write(Byte[] buffer, Int32 offset, Int32 size) at System.Net.ConnectStream.WriteHeaders(Boolean async) And/Or: Message : An existing connection was forcibly closed by the remote host Type : System.Net.Sockets.SocketException, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089 Source : System Help link : ErrorCode : 10054 SocketErrorCode : ConnectionReset NativeErrorCode : 10054 Data : System.Collections.ListDictionaryInternal TargetSite : Int32 Receive(Byte[], Int32, Int32, System.Net.Sockets.SocketFlags) Stack Trace : at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags) at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size) Update We're still working on it. Originally there was a route issue, which was resolved. We're still getting the inner exception with socket errors. We had MS support involved today, and they looked at some traces and network captures. The web service host does round-robin DNS, and they may be responding on a different IP address for the syn syn/ack from one ip, and the next from a different ip. This is not good. This is likely quite specific to our situation, but perhaps it applies to others as well. Microsoft Network Monitor and an application trace got us the information we needed.

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  • Matlab 3d volume visualization and 3d overlay

    - by inf.ig.sh
    Hi, so the question ist pretty much the title. I have a 3d volume loaded as raw data [256, 256, 256] = size(A). It contains only values of zero's and ones, where the 1's represent the structure and 0's the "air". I want to visualize the structure in matlab and then run an algorithm on it and put an overlay on it, let's say in the color red. So to be more precise: How do i visualize the 3d volume. 0's transparent, 1's semitransparent? Plot a line in the 3 d vis as an overlay? I already read the mathworks tutorials and they didn't help. I tried using the set command, but it fails completly saying for every property i try "invalid root property". I hope someone can help.

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  • Interpreting w3wp.exe thread-infos, does mscorwks.dll!StrongNameErrorInfo+0x7688 has a negative impa

    - by Robert
    I am trying to interpret the meaning of "mscorwks.dll!StrongNameErrorInfo+0x7688". I guess it means, that the assembly loaded by the mscorworks.dll has no StrongName? If yes, does this have any negative impact for a web application? Is it safe to assume that the thread count of 107 means, that web application has needed a maximum of 107 concurrent threads to handle incoming requests?

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  • Nullable One To One Relationships with Integer Keys in LINQ-to-SQL

    - by Craig Walker
    I have two objects (Foo and Bar) that have a one-to-zero-or-one relationship between them. So, Foo has a nullable foreign key reference to Bar.ID and a (nullbusted) unique index to enforce the "1" side. Bar.ID is an int, and so Foo.BarID is a nullable int. The problem occurs in the LINQ-to-SQL DBML mapping of .NET types to SQL datatypes. Since int is not a nullable type in .NET, it gets wrapped in a Nullable<int>. However, this is not the same type as int, and so Visual Studio gives me this error message when I try to create the OneToOne Association between them: Cannot create an association "Bar_Foo". Properties do not have matching types: "ID", "BarID". Is there a way around this?

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  • WPF DataGrid programmatic multiple row selection

    - by MicMit
    Is there anything simpler than sample below ? I do have observable collection ( "list" in the code ) bound to DataGrid lstLinks for (int i = 0; i < list.Count ; i++) { object rowItem = lstLinks.Items[i] ; DataGridRow visualItem = (DataGridRow)lstLinks.ItemContainerGenerator.ContainerFromItem(rowItem); if (list[i].Changed) visualItem.IsSelected = false; else visualItem.IsSelected = false; }

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  • Using PHP substr() and strip_tags() while retaining formatting and without breaking HTML

    - by Peter
    I have various HTML strings to cut to 100 characters (of the stripped content, not the original) without stripping tags and without breaking HTML. Original HTML string (288 characters): $content = "<div>With a <span class='spanClass'>span over here</span> and a <div class='divClass'>nested div over <div class='nestedDivClass'>there</div> </div> and a lot of other nested <strong><em>texts</em> and tags in the air <span>everywhere</span>, it's a HTML taggy kind of day.</strong></div>"; Standard trim: Trim to 100 characters and HTML breaks, stripped content comes to ~40 characters: $content = substr($content, 0, 100)."..."; /* output: <div>With a <span class='spanClass'>span over here</span> and a <div class='divClass'>nested div ove... */ Stripped HTML: Outputs correct character count but obviously looses formatting: $content = substr(strip_tags($content)), 0, 100)."..."; /* output: With a span over here and a nested div over there and a lot of other nested texts and tags in the ai... */ Partial solution: using HTML Tidy or purifier to close off tags outputs clean HTML but 100 characters of HTML not displayed content. $content = substr($content, 0, 100)."..."; $tidy = new tidy; $tidy->parseString($content); $tidy->cleanRepair(); /* output: <div>With a <span class='spanClass'>span over here</span> and a <div class='divClass'>nested div ove</div></div>... */ Challenge: To output clean HTML and n characters (excluding character count of HTML elements): $content = cutHTML($content, 100); /* output: <div>With a <span class='spanClass'>span over here</span> and a <div class='divClass'>nested div over <div class='nestedDivClass'>there</div> </div> and a lot of other nested <strong><em>texts</em> and tags in the ai</strong></div>..."; Similar Questions How to clip HTML fragments without breaking up tags Cutting HTML strings without breaking HTML tags

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  • Why allow concatenation of string literals?

    - by Caspin
    I recently got bit by a subtle bug. char ** int2str = { "zero", // 0 "one", // 1 "two" // 2 "three",// 3 nullptr }; assert( values[1] == "one"_s ); // passes assert( values[2] == "two"_s ); // fails If you have godlike code review powers you'll notice I forgot the , after "two". After the considerable effort to find that bug I've got to ask why would anyone ever want this behavior? I can see how this might be useful for macro magic, but then why is this a "feature" in a modern language like python? Have you ever used string literal concatenation in production code?

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  • Java ReentrantReadWriteLocks - how to safely acquire write lock?

    - by Andrzej Doyle
    I am using in my code at the moment a ReentrantReadWriteLock to synchronize access over a tree-like structure. This structure is large, and read by many threads at once with occasional modifications to small parts of it - so it seems to fit the read-write idiom well. I understand that with this particular class, one cannot elevate a read lock to a write lock, so as per the Javadocs one must release the read lock before obtaining the write lock. I've used this pattern successfully in non-reentrant contexts before. What I'm finding however is that I cannot reliably acquire the write lock without blocking forever. Since the read lock is reentrant and I am actually using it as such, the simple code lock.getReadLock().unlock(); lock.getWriteLock().lock() can block if I have acquired the readlock reentrantly. Each call to unlock just reduces the hold count, and the lock is only actually released when the hold count hits zero. EDIT to clarify this, as I don't think I explained it too well initially - I am aware that there is no built-in lock escalation in this class, and that I have to simply release the read lock and obtain the write lock. My problem is/was that regardless of what other threads are doing, calling getReadLock().unlock() may not actually release this thread's hold on the lock if it acquired it reentrantly, in which case the call to getWriteLock().lock() will block forever as this thread still has a hold on the read lock and thus blocks itself. For example, this code snippet will never reach the println statement, even when run singlethreaded with no other threads accessing the lock: final ReadWriteLock lock = new ReentrantReadWriteLock(); lock.getReadLock().lock(); // In real code we would go call other methods that end up calling back and // thus locking again lock.getReadLock().lock(); // Now we do some stuff and realise we need to write so try to escalate the // lock as per the Javadocs and the above description lock.getReadLock().unlock(); // Does not actually release the lock lock.getWriteLock().lock(); // Blocks as some thread (this one!) holds read lock System.out.println("Will never get here"); So I ask, is there a nice idiom to handle this situation? Specifically, when a thread that holds a read lock (possibly reentrantly) discovers that it needs to do some writing, and thus wants to "suspend" its own read lock in order to pick up the write lock (blocking as required on other threads to release their holds on the read lock), and then "pick up" its hold on the read lock in the same state afterwards? Since this ReadWriteLock implementation was specifically designed to be reentrant, surely there is some sensible way to elevate a read lock to a write lock when the locks may be acquired reentrantly? This is the critical part that means the naive approach does not work.

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  • IPv6 multicast addresses: Is the Group ID field effectively 112 bits or 32 bits?

    - by Jeremy Friesner
    Hi all, I'm trying to understand the rules for choosing an IPv6 multicast address Group ID, and the RFC seems somewhat inconsistent. For example, in RFC 2373 section 2.7 this diagram is shown: | 8 | 4 | 4 | 112 bits | +------ -+----+----+---------------------------------------------+ |11111111|flgs|scop| group ID | +--------+----+----+---------------------------------------------+ ... but then in section 2.7.2 it shows this: | 8 | 4 | 4 | 80 bits | 32 bits | +------ -+----+----+---------------------------+-----------------+ |11111111|flgs|scop| reserved must be zero | group ID | +--------+----+----+---------------------------+-----------------+ So my question is, are the upper 80 bits of the Group ID field usable or not? If they are usable, is it only under certain circumstances (e.g. when using non-Ethernet networking technology?) What problems should I expect to experience if I set these bits when multicasting over an Ethernet LAN?

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  • socat usage for FIFO speed vs socket speed on localhost

    - by Fishy
    Hello, As per a suggestion on stackoverflow, to compare IPC on a single machine using a) sockets (TCP) on localhost to localhost b) using FIFOs (between Java and C) To answer (a), I used netcat to gauge transfer speed (91 MBytes/sec)[1] (b) Q: How can I test FIFO write speed using socat? My approach(where /tmp/gus is created using mkfifo on RHEL): dd if=/dev/zero of=/tmp/gus bs=1G count=1 but i get: 1073741824 bytes (1.1 GB) copied, 1.1326 seconds, 948 MB/s Does this mean writing to a FIFO ~10 times faster? Or is my experiment completely wrong ? Thank you Sporsi [1] From machine A to B across 1Gbps link, this number dropped to ~80 MBytes/sec - I expected localhost to be much higher ...

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