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  • Linux: How to find all serial devices (ttyS, ttyUSB and others)?

    - by Thomas Tempelmann
    What is the proper way to get a list of all available serial ports/devices on a Linux system? In other words, when I iterate over all devices in /dev/, how do I tell which ones are serial ports in the classic way, i.e. those usually supporting baud rates and RTS/CTS flow control? The solution would be coded in C. I ask because I am using a 3rd party library that does this clearly wrong: It appears to only iterate over /dev/ttyS*. The problem is that there are, for instance, serial ports over USB (provided by USB-RS232 adapters), and those are listed under /dev/ttyUSB*. And reading the Serial-HOWTO at Linux.org, I get the idea that there'll be other name spaces as well, as time comes. So I need to find the official way to detect serial devices. Problem is that there appears none documented, or I can't find it. I imagine one way would be to open all files from /dev/tty* and call a specific ioctl() on them that is only available on serial devices. Would that be a good solution, though?

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  • Lightweight spinlocks built from GCC atomic operations?

    - by Thomas
    I'd like to minimize synchronization and write lock-free code when possible in a project of mine. When absolutely necessary I'd love to substitute light-weight spinlocks built from atomic operations for pthread and win32 mutex locks. My understanding is that these are system calls underneath and could cause a context switch (which may be unnecessary for very quick critical sections where simply spinning a few times would be preferable). The atomic operations I'm referring to are well documented here: http://gcc.gnu.org/onlinedocs/gcc-4.4.1/gcc/Atomic-Builtins.html Here is an example to illustrate what I'm talking about. Imagine a RB-tree with multiple readers and writers possible. RBTree::exists() is read-only and thread safe, RBTree::insert() would require exclusive access by a single writer (and no readers) to be safe. Some code: class IntSetTest { private: unsigned short lock; RBTree<int>* myset; public: // ... void add_number(int n) { // Aquire once locked==false (atomic) while (__sync_bool_compare_and_swap(&lock, 0, 0xffff) == false); // Perform a thread-unsafe operation on the set myset->insert(n); // Unlock (atomic) __sync_bool_compare_and_swap(&lock, 0xffff, 0); } bool check_number(int n) { // Increment once the lock is below 0xffff u16 savedlock = lock; while (savedlock == 0xffff || __sync_bool_compare_and_swap(&lock, savedlock, savedlock+1) == false) savedlock = lock; // Perform read-only operation bool exists = tree->exists(n); // Decrement savedlock = lock; while (__sync_bool_compare_and_swap(&lock, savedlock, savedlock-1) == false) savedlock = lock; return exists; } }; (lets assume it need not be exception-safe) Is this code indeed thread-safe? Are there any pros/cons to this idea? Any advice? Is the use of spinlocks like this a bad idea if the threads are not truly concurrent? Thanks in advance. ;)

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  • Why does Clojure hang after hacing performed my calculations?

    - by Thomas
    Hi all, I'm experimenting with filtering through elements in parallel. For each element, I need to perform a distance calculation to see if it is close enough to a target point. Never mind that data structures already exist for doing this, I'm just doing initial experiments for now. Anyway, I wanted to run some very basic experiments where I generate random vectors and filter them. Here's my implementation that does all of this (defn pfilter [pred coll] (map second (filter first (pmap (fn [item] [(pred item) item]) coll)))) (defn random-n-vector [n] (take n (repeatedly rand))) (defn distance [u v] (Math/sqrt (reduce + (map #(Math/pow (- %1 %2) 2) u v)))) (defn -main [& args] (let [[n-str vectors-str threshold-str] args n (Integer/parseInt n-str) vectors (Integer/parseInt vectors-str) threshold (Double/parseDouble threshold-str) random-vector (partial random-n-vector n) u (random-vector)] (time (println n vectors (count (pfilter (fn [v] (< (distance u v) threshold)) (take vectors (repeatedly random-vector)))))))) The code executes and returns what I expect, that is the parameter n (length of vectors), vectors (the number of vectors) and the number of vectors that are closer than a threshold to the target vector. What I don't understand is why the programs hangs for an additional minute before terminating. Here is the output of a run which demonstrates the error $ time lein run 10 100000 1.0 [null] 10 100000 12283 [null] "Elapsed time: 3300.856 msecs" real 1m6.336s user 0m7.204s sys 0m1.495s Any comments on how to filter in parallel in general are also more than welcome, as I haven't yet confirmed that pfilter actually works.

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  • Cannot connect Linux XAMPP PHP to MS SQL database.

    - by Jim
    I've searched many sites without success. I'm using XAMPP 1.7.3a on Ubuntu 9.1. I have used the methods found at http://www.webcheatsheet.com/PHP/connect_mssql_database.php, they all fail. I am able to "connect" with a linked database through MS Access, however, that is not an acceptable solution as not all users will have Access. The first method (at webcheatsheet) uses mssql_connect, et.al. but I get this error from the mssql_connect() call: Warning: mssql_connect() [function.mssql-connect]: Unable to connect to server: [my server] in [my code] [my server] is the server address, I have used both the host name and the IP address. [my code] is a reference to the file and line number in my .php file. Is there a log file somewhere that would have more information about the failure, both on my machine and the MS SQL server? We do not have a bona-fide DBA, so I will need specific information to pass on if the issue seems to be on the server side. All assistance is appreciated, including RTFM when the location of the M is provided! Thanks

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  • Could an ontology suitably replace an RDBMS for a web app?

    - by Thomas
    I'm considering storing the content of a web app in an RDF or OWL ontology instead of an RDBMS. However, when I research ontologies they seem to always exist in the context of publicly accessible data stores serving as the backbone of the semantic web. I've never heard of them being used as the content engine behind a web app. Is it reasonable to use an ontology instead of an RDBMS for such an application? (Again, this is just for content. User data, commerce and stuff like that will stay in a database as I see no need to reinvent the wheel there.)

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  • Suggestions for debugging print stylesheets?

    - by Jim Puls
    I've recently been working on a print stylesheet for a website, and I realized that I was at a loss for effective ways to tweak it. It's one thing to have a reload cycle for working on the on-screen layout: change code command-tab reload but that whole process gets much more arduous when you're trying to print: change code command-tab reload print squint at print-preview image open PDF in Preview for further inspection Are there tools I'm missing out on here? Does WebKit's inspector have a "pretend this is paged media" checkbox? Is there some magic that Firebug (shudder) can do?

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  • how to redirect terminal contents to a jtextpane?

    - by sonu thomas
    hi.. I was trying to run a java class file using java code.The aim was to direct the executing sequence of the terminal of fedora 10 into a frame with a textpane. My code is: import java.io.DataInputStream; import java.io.IOException; import javax.swing.JDialog; import javax.swing.JFrame; import javax.swing.JOptionPane; import javax.swing.JPanel; import javax.swing.JTextArea; import javax.swing.JTextPane; //import sun.reflect.ReflectionFactory.GetReflectionFactoryAction; public class file { /** * @param args */ /** * @param args * @throws IOException */ public static void main(String[] args) throws IOException{ // TODO Auto-generated method stub JDialog jj = new JDialog(); jj.setTitle("helllo"); String sssub1,sssub2,sssub3; String ss="C:/Users/sonu/Desktop/ourIDE/src/src/nn.java"; JPanel n = new JPanel(); jj.setContentPane(n); JTextPane tpn2=new JTextPane(); jj.getContentPane().add(tpn2); jj.setVisible(true); Runtime runtime; Process process; if(ss.indexOf(" ")==-1) { try { runtime= Runtime.getRuntime(); sssub1="/home/ss/Desktop/src/"; sssub2="nn"; process=runtime.exec("sh jrun.sh "+sssub1+" "+sssub2); DataInputStream data=new DataInputStream(process.getInputStream()); DataInputStream data_data=new DataInputStream(process.getErrorStream()); String s="",t=""; int ch; while((ch=data.read())!=-1){ s=s+(char)ch; } data.close(); while((ch=data_data.read())!=-1){ t=t+(char)ch; } data_data.close(); if(t.equals("")) { s+="\nNormal Termination."; tpn2.setText(s); } else tpn2.setText(t); }catch(Exception e){ System.out.println("Error executing file==>"+e);} } } } The content of **jrun.sh** is cd $1 java $2 When the content of **nn.java** was this: import java.io.*; class nn { public static void main(String[] ar)throws IOException { int i=90; BufferedReader dt = new BufferedReader(new InputStreamReader(System.in)); System.out.println("Enter"); //i=Integer.parseInt(dt.readLine()); line--notable System.out.println("i="+i); } } It worked smoothly But when I remove the comment on line--notable,it gave me Textpane with no content. The problem is : I cant read an input from nn.java Kindly give me a solution... If i am able to: get the terminal pop up with executing the nn.class,and i am able to enter the input,then it will do... Thanks in advance...

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  • Requiring library consumers reference additional assembly when using certain types

    - by Thomas G. Mayfield
    I have library code that uses ICSharpCode.SharpZipLib under the hood to make it easy to use ZIP files as data sources when running integration tests. As it stands, if I reference my library from another project, the other project will compile just fine, but when it accesses the code that uses SharpZipLib, I get an exception for it not finding the zip library: failed: System.IO.FileNotFoundException : Could not load file or assembly 'ICSharpCode.SharpZipLib, Version=0.85.5.452, Culture=neutral, PublicKeyToken=1b03e6acf1164f73' or one of its dependencies. The system cannot find the file specified. If the types in my library derived from a class in SharpZipLib, it'd generate a compile error CS0012. What other ways are there for triggering a CS0012, so that using code that requires SharpZipLib (but doesn't clearly indicate it) would cause consumer code to fail compilation? I've had similar problems in the past when I've used libraries like DeftTech.DuckTyping under the hood. I'd add my library code to a new project, start working, compile, run, and then suddenly hit an edge case that I'd used duck typing to get around and get a runtime error. What I'd most like is to have the same behavior as if I'd derived from a type in the 3rd-party library, so that a reference to my derived type generates a CS0012: The type 'type' is defined in an assembly that is not referenced. You must add a reference to assembly 'assembly'.

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  • Can I check wheter Linq 2 SQL's DataContext is tracking entities?

    - by Thomas Jespersen
    We want to throw an exception, if a user calls DataContext.SubmitChanges() and the DataContext is not tracking anything. That is... it is OK to call SubmitChanges if there are no inserts, updates or deletes. But we want to ensure that the developer didn't forget to attach the entity to the DataContext. Even better... is it possible to get a collection of all entities that the DataContext is tracking (including those that are not changed)? PS: The last question I asked were answered with: "do it this way instead"... please don't :-)

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  • How do I include full PartCover results with TeamCity 5?

    - by Jim Geurts
    Hi, I'm trying to get PartCover reports to generate correctly in TeamCity 5.0. When I click the Code Coverage tab in the build details, the reports are empty. I'm using the sln2008 build agent and my PartCoverage settings are as follows: Include Patterns: [*]* Report XSLT: C:\Program Files\PartCover .NET 2.3\xslt\Report By Assembly.xslt=>ByAssembly.html C:\Program Files\PartCover .NET 2.3\xslt\Report By Class.xslt=>ByClass.html Bonus points if you can describe how to include those reports (or just the important parts) with the email that TeamCity sends for successful/failed builds. I would like to continue using the sln2008 build agent, if possible, and not a different build agent.

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  • Push a ViewController and It Pops Right Back

    - by Jim Bonner
    I have a view controller with a table view and a UISearchBar. When the view controller is first brought up, the table is populated. A click on a table row pushes another view controller, it animates up and then pops right back down and returns me to the table. It does this whether the search bar has been used or not. I do this push pop kind of action in several view controllers with not problem. My guess is that the UISearchBar is somehow getting in the way. Any one have any idea as to what I'm doing wrong?

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  • How do I localize the jQuery DatePicker?

    - by Thomas Eyde
    I really need a localized dropdown calendar. An English calendar doesn't exactly communicate excellence on a Norwegian website ;-) I have experimented with the jQuery DatePicker, their website says it can be localized, however that doesn't seem to work. I am using ASPNET.MVC, and I really want to stick to one javascript library. In this case jQuery. The ajax toolkit calendar would be acceptable, if only it too would display Norwegian names. Update: Awesome! I see I am missing the language files, a not so minor detail :-)

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  • How to bind a table in a dataset to a WPF datagrid in C# and XAML

    - by Jim Thomas
    I have been searching to hours for something very simple: bind a WPF datagrid to a datatable in order to see the columns at design-time. I can’t get any of the examples to work for me. Here is the C# code to populate the datatable InfoWork inside the dataset info: info = new Info(); InfoTableAdapters.InfoWorkTableAdapter adapter = new InfoTableAdapters.InfoWorkTableAdapter(); adapter.Fill(info.InfoWork); The problem is no matter how I declare ‘info’ or ‘infoWork’ Visual Studio/XAML can’t find it. I have tried: <Window.Resources> <ObjectDataProvider x:Key="infoWork" ObjectType="{x:Type local:info}" /> </Window.Resources> I have also tried this example from wpf.codeplex, but XAML doesn’t even like the “local:” keyword! <Window.Resources> <local:info x:Key="infoWork"/> </Window.Resources> There are really two main questions here: 1) How do I declare the table InfoWork in C# so that XAML can see it? I tried declaring it Public in the window class that XAML exists in with no success. 2) How do I declare the windows resource in XAML, specifcally the datatable inside the dataset? Out of curiosity, is there a reason that ItemsSource just doesn't show up as a property that be set in the properties design window?

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  • How long should it take a senior developer to solve FizzBuzz during an interview?

    - by Jim McKeeth
    Assuming: Typical interview stress levels (I am watching) Using familiar IDE and program language (their choice on their PC!) Given adequate explanation and immediate answers to questions Able to compile code and check answers / progress Claims to be a senior level programmer How long should it take an interviewee to answer FizzBuzz correctly? Edit: FizzBuzz: Write a program that prints the numbers from 1 to 100. But for multiples of three print "Fizz" instead of the number and for the multiples of five print "Buzz". For numbers which are multiples of both three and five print "FizzBuzz". Edit: It isn't so much that if they take more then X minutes they are disqualified, but I am curious if I should just cut them loose after they work on it for half hour.

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  • Is the Silverstripe CMS as easy to deploy, maintain, and develop on as it appears?

    - by Thomas Owens
    Although I haven't thought about deploying it on my own site, someone I know sent me a link to a CMS called SilverStripe that I've never heard of before. I read their site, looked at and played around with their demo, and so on. It looks like it's a CMS backed by a custom PHP framework that they call Sapphire. And from what I can gather on their website and using their demo, it potentially might be as good and easy as they say (once you get past any learning curve, which appears to be small, considering it looks a lot like other PHP frameworks and CMSes). Has anyone here ever deployed, maintained, or developed a CMS using SilverStripe? If so, could you shed some light on it, from a developer's point-of-view? I also found this earlier question about SilverStripe here on StackOverflow, but I'm more interested from a development point of view than a user or administrator point of view.

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  • Automatically install and launch a code-signed application from Safari

    - by Thomas Jung
    Is it possible and if so what are the steps necessary to package (or build) a Mac OS X application and code-sign it so that it can be downloaded with Safari and automatically launch? ... possibly after the user responds to some sort of dialog explaining that it is a signed application and the publisher has been verified. An example of the user experience I am trying to create is "installing Google Chrome for the first time on Windows", which is a 3-click, less-than-a-minute process. For the concerned among you: I am not trying to create a drive-by download. I am fine with some sort of intermittent user step approving the download. I just want to make the installation as quick and painless as possible and not require the user drag the app from a mounted DMG into the application folder. This may not 100% jibe with established Mac OS X user interaction guidelines, but it would work better for the not-power users. I only need the high-level steps or pointers to resources ... my google-fu was weak on this one.

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  • In WPF, accessing containers within ListBox

    - by Jim
    I'm creating a DerivedListBox : ListBox and a DerivedHeaderedContentControl : HeaderedContentControl, which will serve as a container for each item in the ListBox. In order to calculate the size available for the expanded content of the DerivedHeaderedContentControls, I am storing each container object in a list within the DerivedListBox. This way I can calculate the height of the headers of each DerivedHeaderedContentControl and subtract that from the total size available to the DerivedListBox. This would be the size available for the expanded content of a DerivedHeaderedContentControl. public class DerivedHeaderedContentControl : HeaderedContentControl { // Do some binding to DerivedListBox to calculate height. } public class DerivedListBox : ListBox { private List<DerivedHeaderedContentControl> containers; protected override DependencyObject GetContainerForItemOverride() { DerivedHeaderedContentControl val = new DerivedHeaderedContentControl(); this.containers.Add(val); return val; } // Do some binding to calculate height available for an expanded // container by iterating over containers. } The problem comes in when the DerivedListBox's ItemsSource is cleared (or an item in the items source is removed). How can I determine when the ItemsSource is cleared so that I can clear the containers list?

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  • Linked List Design

    - by Jim Scott
    The other day in a local .NET group I attend the following question came up: "Is it a valid interview question to ask about Linked Lists when hiring someone for a .NET development position?" Not having a computer sciense degree and being a self taught developer my response was that I did not feel it was appropriate as I in 5 years of developer with .NET had never been exposed to linked lists and did not hear any compeling reason for a use for one. However the person commented that it is a very common interview question so I decided when I left that I would do some reasearch on linked lists and see what I might be missing. I have read a number of posts on stack overflow and various google searches and decided the best way to learn about them was to write my own .NET classes to see how they worked from the inside out. Here is my class structure Single Linked List Constructor public SingleLinkedList(object value) Public Properties public bool IsTail public bool IsHead public object Value public int Index public int Count private fields not exposed to a property private SingleNode firstNode; private SingleNode lastNode; private SingleNode currentNode; Methods public void MoveToFirst() public void MoveToLast() public void Next() public void MoveTo(int index) public void Add(object value) public void InsertAt(int index, object value) public void Remove(object value) public void RemoveAt(int index) Questions I have: What are typical methods you would expect in a linked list? What is typical behaviour when adding new records? For example if I have 4 nodes and I am currently positioned in the second node and perform Add() should it be added after or before the current node? Or should it be added to the end of the list? Some of the designs I have seen explaining things seem to expose outside of the LinkedList class the Node object. In my design you simply add, get, remove values and know nothing about any node object. Should the Head and Tail be placeholder objects that are only used to define the head/tail of the list? I require my Linked List be instantiated with a value which creates the first node of the list which is essentially the head and tail of the list. Would you change that ? What should the rules be when it comes to removing nodes. Should someone be able to remove all nodes? Here is my Double Linked List Constructor public DoubleLinkedList(object value) Properties public bool IsHead public bool IsTail public object Value public int Index public int Count Private fields not exposed via property private DoubleNode currentNode; Methods public void AddFirst(object value) public void AddLast(object value) public void AddBefore(object existingValue, object value) public void AddAfter(object existingValue, object value) public void Add(int index, object value) public void Add(object value) public void Remove(int index) public void Next() public void Previous() public void MoveTo(int index)

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  • Get children count via HQL

    - by Thomas Lötzer
    Hi, I have a one-to-many mapping between a parent entity and child entities. Now I need to find the number of children associated with each parent for a list of parents. I am trying to do this with HQL but I am not sure how I can get the list of parents in there. Also, I don't know how I can return the entity itself and not just its ID. My current HQL query is: select new map(parent.id as parentId, count(*) as childCount) from Parent parent left join parent.children children group by parent.id but this only returns the ID and does not filter on specific parents. EDIT Based on Pascal's answer I have modified the query to select new map(parent as parent, count(elements(parent.children)) as childCount) from Parent parent group by parent That does work, but is prohibitively slow: 30 seconds instead of 400 ms on the same database.

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  • std::map operator[] and automatically created new objects

    - by thomas-gies
    I'm a little bit scared about something like this: std::map<DWORD, DWORD> tmap; tmap[0]+=1; tmap[0]+=1; tmap[0]+=1; Since DWORD's are not automatically initialized, I'm always afraid of tmap[0] being a random number that is incremented. How does the map know hot to initialize a DWORD if the runtime does not know how to do it? Is it guaranteed, that the result is always tmap[0] == 3?

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  • Applying Domain Model on top of Linq2Sql entities

    - by Thomas
    I am trying to practice the model first approach and I am putting together a domain model. My requirement is pretty simple: UserSession can have multiple ShoppingCartItems. I should start off by saying that I am going to apply the domain model interfaces to Linq2Sql generated entities (using partial classes). My requirement translates into three database tables (UserSession, Product, ShoppingCartItem where ProductId and UserSessionId are foreign keys in the ShoppingCartItem table). Linq2Sql generates these entities for me. I know I shouldn't even be dealing with the database at this point but I think it is important to mention. The aggregate root is UserSession as a ShoppingCartItem can not exist without a UserSession but I am unclear on the rest. What about Product? It is defiently an entity but should it be associated to ShoppingCartItem? Here are a few suggestion (they might all be incorrect implementations): public interface IUserSession { public Guid Id { get; set; } public IList<IShoppingCartItem> ShoppingCartItems{ get; set; } } public interface IShoppingCartItem { public Guid UserSessionId { get; set; } public int ProductId { get; set; } } Another one would be: public interface IUserSession { public Guid Id { get; set; } public IList<IShoppingCartItem> ShoppingCartItems{ get; set; } } public interface IShoppingCartItem { public Guid UserSessionId { get; set; } public IProduct Product { get; set; } } A third one is: public interface IUserSession { public Guid Id { get; set; } public IList<IShoppingCartItemColletion> ShoppingCartItems{ get; set; } } public interface IShoppingCartItemColletion { public IUserSession UserSession { get; set; } public IProduct Product { get; set; } } public interface IProduct { public int ProductId { get; set; } } I have a feeling my mind is too tightly coupled with database models and tables which is making this hard to grasp. Anyone care to decouple?

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  • Is it possible to easily convert SqlCommand to T-SQL string ?

    - by Thomas Wanner
    I have a populated SqlCommand object containing the command text and parameters of various database types along with their values. What I need is a T-SQL script that I could simply execute that would have the same effect as calling the ExecuteNonQuery method on the command object. Is there an easy way to do such "script dump" or do I have to manually construct such script from the command object ?

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