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• A new SQL, a new Analysis Services, a new Workshop! #ssas #sql2012

  - by Marco Russo (SQLBI)

  One week ago Microsoft SQL Server 2012 finally debuted with a virtual launch event and you can find many intro sessions there (20 minutes each). There is a lot of new content available if you want to learn more about SQL 2012 and in this blog post I’d like to provide a few link to sessions, documents, bits and courses that are available now or very soon. First of all, the release of Analysis Services 2012 has finally released PowerPivot 2012 (many of us called it PowerPivot v2 before this official name) and also the new Data Mining Add-in for Microsoft Office 2010, now available also for Excel 64bit! And, of course, don’t miss the Microsoft SQL Server 2012 Feature Pack, there are a lot of upgrades for both DBAs and developers. I just discovered there is a new LocalDB version of SQL Express that can run in user mode without any setup. Is this the end of SQL CE? But now, back to Analysis Services: if you want some tutorial on Tabular, the Microsoft Virtual Academy has a whole track dedicated to Analysis Services 2012 but you will probably be interested also in the one about Reporting Services 2012. If you think that virtual is good but it’s not enough, there are plenty of conferences in the coming months – these are just those where I and Alberto will deliver some SSAS Tabular presentations: SQLBits X, London, March 29-31, 2012: if you are in London or want a good reason to go, this is the most important SQL Server event in Europe this year, no doubts about it. And not only because of the high number of attendees, but also because there is an impressive number of speakers (excluding me, of course) coming from all over the world. This is an event second only to PASS Summit in Seattle so there are no good reasons to not attend it. Microsoft SQL Server & Business Intelligence Conference 2012, Milan, March 28-29, 2012: this is an Italian conference so the language might be a barrier, but many of us also speak English and the food is good! Just a few seats still available. TechEd North America, Orlando, June 11-14, 2012: you know, this is a big event and it contains everything – if you want to spend a whole day learning the SSAS Tabular model with me and Alberto, don’t miss our pre-conference day “Using BISM Tabular in Microsoft SQL Server Analysis Services 2012” (be careful, it is on June 10, a nice study-Sunday!). TechEd Europe, Amsterdam, June 26-29, 2012: the European version of TechEd provides almost the same content and you don’t have to go overseas. We also run the same pre-conference day “Using BISM Tabular in Microsoft SQL Server Analysis Services 2012” (in this case, it is on June 25, that’s a regular Monday). I and Alberto will also speak at some user group meeting around Europe during… well, we’re going to travel a lot in the next months. In fact, if you want to get a complete training on SSAS Tabular, you should spend two days with us in one of our SSAS Tabular Workshop! We prepared a 2-day seminar, a very intense one, that start from the simple tabular modeling and cover architecture, DAX, query, advanced modeling, security, deployment, optimization, monitoring, relationships with PowerPivot and Multidimensional… Really, there are a lot of stuffs here! We announced the first dates in Europe and also an online edition optimized for America’s time zone: Apr 16-17, 2012 – Amsterdam, Netherlands Apr 26-27, 2012 – Copenhagen, Denmark May 7-8, 2012 – Online for America’s time zone May 14-15, 2012 – Brussels, Belgium May 21-22, 2012 – Oslo, Norway May 24-25, 2012 – Stockholm, Sweden May 28-29, 2012 – London, United Kingdom May 31-Jun 1, 2012 – Milan, Italy (Italian language) Also Chris Webb will join us in this workshop and in every date you can find who is the speaker on the web site. The course is based on our upcoming book, almost 600 pages (!) about SSAS Tabular, an incredible effort that will be available very soon in a preview (rough cuts from O’Reilly) and will be on the shelf in May. I will provide a link to order it as soon as we have one! And if you think that this is not enough… you’re right! Do you know what is the only thing you can do to optimize your Tabular model? Optimize your DAX code. Learning DAX is easy, mastering DAX requires some knowledge… and our DAX Advanced Workshop will provide exactly the required content. Public classes will be available later this year, by now we just deliver it on demand.

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• Opening URL in New Tab doesn't work in existing, programmatically-opened New Window (Firefox)

  - by seth

  I am building a web app, for myself, to control some servers on my home network, and discovered what I think is very odd behavior in Firefox. If you open a pop-up, via javascript, in Firefox, is it then impossible to open a new tab, via javascript in that pop-up? If not impossible, how do you do it? Given a clean, default Firefox 3.6.3 installation... If I open a page in Firefox and then call var my_window = window.open('http://www.google.com','_blank','top=10'); A brand new "pop-up" window opens. However, if instead I call var my_window = window.open('http://www.google.com'); A get a new tab. HOWEVER... If I call the first version var my_window = window.open('http://www.google.com','_blank','top=10'); And then in the new "pop-up" that opens, I call var my_window = window.open('http://www.google.com'); It opens a new tab in the original window, not a new tab in the pop-up. This seems very odd, and not intuitive at all. Why would the call in the pop-up open a tab in the "parent" window?

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• Bad_alloc exception when using new for a struct c++

  - by bsg

  Hi, I am writing a query processor which allocates large amounts of memory and tries to find matching documents. Whenever I find a match, I create a structure to hold two variables describing the document and add it to a priority queue. Since there is no way of knowing how many times I will do this, I tried creating my structs dynamically using new. When I pop a struct off the priority queue, the queue (STL priority queue implementation) is supposed to call the object's destructor. My struct code has no destructor, so I assume a default destructor is called in that case. However, the very first time that I try to create a DOC struct, I get the following error: Unhandled exception at 0x7c812afb in QueryProcessor.exe: Microsoft C++ exception: std::bad_alloc at memory location 0x0012f5dc.. I don't understand what's happening - have I used up so much memory that the heap is full? It doesn't seem likely. And it's not as if I've even used that pointer before. So: first of all, what am I doing that's causing the error, and secondly, will the following code work more than once? Do I need to have a separate pointer for each struct created, or can I re-use the same temporary pointer and assume that the queue will keep a pointer to each struct? Here is my code: struct DOC{ int docid; double rank; public: DOC() { docid = 0; rank = 0.0; } DOC(int num, double ranking) { docid = num; rank = ranking; } bool operator>( const DOC & d ) const { return rank > d.rank; } bool operator<( const DOC & d ) const { return rank < d.rank; } }; //a lot of processing goes on here; when a matching document is found, I do this: rank = calculateRanking(table, num); //if the heap is not full, create a DOC struct with the docid and rank and add it to the heap if(q.size() < 20) { doc = new DOC(num, rank); q.push(*doc); doc = NULL; } //if the heap is full, but the new rank is greater than the //smallest element in the min heap, remove the current smallest element //and add the new one to the heap else if(rank > q.top().rank) { q.pop(); cout << "pushing doc on to queue" << endl; doc = new DOC(num, rank); q.push(*doc); } Thank you very much, bsg.

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• Authenticating clients in the new WCF Http stack

  - by cibrax

  About this time last year, I wrote a couple of posts about how to use the “Interceptors” from the REST starker kit for implementing several authentication mechanisms like “SAML”, “Basic Authentication” or “OAuth” in the WCF Web programming model. The things have changed a lot since then, and Glenn finally put on our hands a new version of the Web programming model that deserves some attention and I believe will help us a lot to build more Http oriented services in the .NET stack. What you can get today from wcf.codeplex.com is a preview with some cool features like Http Processors (which I already discussed here), a new and improved version of the HttpClient library, Dependency injection and better TDD support among others. However, the framework still does not support an standard way of doing client authentication on the services (This is something planned for the upcoming releases I believe). For that reason, moving the existing authentication interceptors to this new programming model was one of the things I did in the last few days. In order to make authentication simple and easy to extend,  I first came up with a model based on what I called “Authentication Interceptors”. An authentication interceptor maps to an existing Http authentication mechanism and implements the following interface, public interface IAuthenticationInterceptor{ string Scheme { get; } bool DoAuthentication(HttpRequestMessage request, HttpResponseMessage response, out IPrincipal principal);} An authentication interceptors basically needs to returns the http authentication schema that implements in the property “Scheme”, and implements the authentication mechanism in the method “DoAuthentication”. As you can see, this last method “DoAuthentication” only relies on the HttpRequestMessage and HttpResponseMessage classes, making the testing of this interceptor very simple (There is no need to do some black magic with the WCF context or messages). After this, I implemented a couple of interceptors for supporting basic authentication and brokered authentication with SAML (using WIF) in my services. The following code illustrates how the basic authentication interceptors looks like. public class BasicAuthenticationInterceptor : IAuthenticationInterceptor{ Func<UsernameAndPassword, bool> userValidation; string realm;  public BasicAuthenticationInterceptor(Func<UsernameAndPassword, bool> userValidation, string realm) { if (userValidation == null) throw new ArgumentNullException("userValidation");  if (string.IsNullOrEmpty(realm)) throw new ArgumentNullException("realm");  this.userValidation = userValidation; this.realm = realm; }  public string Scheme { get { return "Basic"; } }  public bool DoAuthentication(HttpRequestMessage request, HttpResponseMessage response, out IPrincipal principal) { string[] credentials = ExtractCredentials(request); if (credentials.Length == 0 || !AuthenticateUser(credentials[0], credentials[1])) { response.StatusCode = HttpStatusCode.Unauthorized; response.Content = new StringContent("Access denied"); response.Headers.WwwAuthenticate.Add(new AuthenticationHeaderValue("Basic", "realm=" + this.realm));  principal = null;  return false; } else { principal = new GenericPrincipal(new GenericIdentity(credentials[0]), new string[] {});  return true; } }  private string[] ExtractCredentials(HttpRequestMessage request) { if (request.Headers.Authorization != null && request.Headers.Authorization.Scheme.StartsWith("Basic")) { string encodedUserPass = request.Headers.Authorization.Parameter.Trim();  Encoding encoding = Encoding.GetEncoding("iso-8859-1"); string userPass = encoding.GetString(Convert.FromBase64String(encodedUserPass)); int separator = userPass.IndexOf(':');  string[] credentials = new string[2]; credentials[0] = userPass.Substring(0, separator); credentials[1] = userPass.Substring(separator + 1);  return credentials; }  return new string[] { }; }  private bool AuthenticateUser(string username, string password) { var usernameAndPassword = new UsernameAndPassword { Username = username, Password = password };  if (this.userValidation(usernameAndPassword)) { return true; }  return false; }} This interceptor receives in the constructor a callback in the form of a Func delegate for authenticating the user and the “realm”, which is required as part of the implementation. The rest is a general implementation of the basic authentication mechanism using standard http request and response messages. I also implemented another interceptor for authenticating a SAML token with WIF. public class SamlAuthenticationInterceptor : IAuthenticationInterceptor{ SecurityTokenHandlerCollection handlers = null;  public SamlAuthenticationInterceptor(SecurityTokenHandlerCollection handlers) { if (handlers == null) throw new ArgumentNullException("handlers");  this.handlers = handlers; }  public string Scheme { get { return "saml"; } }  public bool DoAuthentication(HttpRequestMessage request, HttpResponseMessage response, out IPrincipal principal) { SecurityToken token = ExtractCredentials(request);  if (token != null) { ClaimsIdentityCollection claims = handlers.ValidateToken(token);  principal = new ClaimsPrincipal(claims);  return true; } else { response.StatusCode = HttpStatusCode.Unauthorized; response.Content = new StringContent("Access denied");  principal = null;  return false; } }  private SecurityToken ExtractCredentials(HttpRequestMessage request) { if (request.Headers.Authorization != null && request.Headers.Authorization.Scheme == "saml") { XmlTextReader xmlReader = new XmlTextReader(new StringReader(request.Headers.Authorization.Parameter));  var col = SecurityTokenHandlerCollection.CreateDefaultSecurityTokenHandlerCollection(); SecurityToken token = col.ReadToken(xmlReader);  return token; }  return null; }}This implementation receives a “SecurityTokenHandlerCollection” instance as part of the constructor. This class is part of WIF, and basically represents a collection of token managers to know how to handle specific xml authentication tokens (SAML is one of them). I also created a set of extension methods for injecting these interceptors as part of a service route when the service is initialized. var basicAuthentication = new BasicAuthenticationInterceptor((u) => true, "ContactManager");var samlAuthentication = new SamlAuthenticationInterceptor(serviceConfiguration.SecurityTokenHandlers); // use MEF for providing instancesvar catalog = new AssemblyCatalog(typeof(Global).Assembly);var container = new CompositionContainer(catalog);var configuration = new ContactManagerConfiguration(container); RouteTable.Routes.AddServiceRoute<ContactResource>("contact", configuration, basicAuthentication, samlAuthentication);RouteTable.Routes.AddServiceRoute<ContactsResource>("contacts", configuration, basicAuthentication, samlAuthentication); In the code above, I am injecting the basic authentication and saml authentication interceptors in the “contact” and “contacts” resource implementations that come as samples in the code preview. I will use another post to discuss more in detail how the brokered authentication with SAML model works with this new WCF Http bits. The code is available to download in this location.

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• How to explain my 5 burnt-out years off to a new employer?

  - by user17332

  Five years ago, I lost my ability to concentrate long-term, and therefore ability to code with professional efficiency. I know why it happened, I understood how it happened, and on top of being able to re-create my calm and thus relaxed focus, I overcame the original (rooted in childhood) reason why my mind tilted on the overall situation back then; My understanding isn't rooted in words that a psychologist told me, I actually grokked them first-hand. I'm pretty much confident to be able to churn out productivity, possibly even more so than pre-burnout. I also never lost my interest in code nor did I stray from trying to get my abilities back; I kept my knowledge up to date (I could always relatively painlessly learn things coding-related, just not apply them) and thus can say that I'm a better developer than before, even if my average LOC-count over those years is abysmally low. On the other hand, now I have a biography that includes more time on the dole than in a job. What would convince you, as an employer, to give my application a chance? I don't believe I should just keep the whole topic out of it.

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• What strategy to use when starting in a new project with no documentation?

  - by Amir Rezaei

  Which is the best why to go when there are no documentation? For example how do you learn business rules? I have done the following steps: Since we are using a ORM tool I have printed a copy of database schema where I can see relations between objects. I have made a list of short names/table names that I will get explained. The project is client/server enterprise application using MVVM pattern.

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• What strategy to use when starting in a new project with no documentations?

  - by Amir Rezaei

  Which is the best why to go when there are no documentations? For example how do you learn business rules? I have done the following steps: Since we are using a ORM tool I have printed a copy of database schema where I can se relations between objects. I have made a list of short names/table names that I will get explained. The project is client/server enterprise application using MVVM pattern.

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• Need help understanding "TypeError: default __new__ takes no parameters" error in python

  - by Gordon Fontenot

  For some reason I am having trouble getting my head around __init__ and __new__. I have a bunch of code that runs fine from the terminal, but when I load it as a plugin for Google Quick Search Box, I get the error TypeError: default __new__ takes no parameters. I have been reading about the error, and it's kind of making my brain spin. As it stands I have 3 classes, with no sub-classes, each class has it's own defs. I never use def __init__ or def __new__, but I have gotten the distinct feeling that these are the functions (or the lack thereof) that would be giving me the error. I have no idea how to summarize the code down to a snippet that would be helpful here, since I'm a bit over my head, but the entire script can be found at github. Not expecting anyone to bugfix my code for me, I am just at my wit's end on this. A simple (plain english, not the quote from the python docs which I have read 20 times and still don't really understand) explination of why this error would pop up, or why I should be, or not be, using the __init__ and/or __new__ functions would be seriously appreciated. Thanks for any help you can give in advance.

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• error C3662: override specifier 'new' only allowed on member functions of managed classes

  - by William

  Okay, so I'm trying to override a function in a parent class, and getting some errors. here's a test case #include <iostream> using namespace std; class A{ public: int aba; void printAba(); }; class B: public A{ public: void printAba() new; }; void A::printAba(){ cout << "aba1" << endl; } void B::printAba() new{ cout << "aba2" << endl; } int main(){ A a = B(); a.printAba(); return 0; } And here's the errors I'm getting: Error 1 error C3662: 'B::printAba' : override specifier 'new' only allowed on member functions of managed classes c:\users\test\test\test.cpp 12 test Error 2 error C2723: 'B::printAba' : 'new' storage-class specifier illegal on function definition c:\users\test\test\test.cpp 19 test How the heck do I do this?

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• The new operator in C# isn't overriding base class member

  - by Dominic Zukiewicz

  I am confused as to why the new operator isn't working as I expected it to. Note: All classes below are defined in the same namespace, and in the same file. This class allows you to prefix any content written to the console with some provided text. public class ConsoleWriter { private string prefix; public ConsoleWriter(string prefix) { this.prefix = prefix; } public void Write(string text) { Console.WriteLine(String.Concat(prefix,text)); } } Here is a base class: public class BaseClass { protected static ConsoleWriter consoleWriter = new ConsoleWriter(""); public static void Write(string text) { consoleWriter.Write(text); } } Here is an implemented class: public class NewClass : BaseClass { protected new static ConsoleWriter consoleWriter = new ConsoleWriter("> "); } Now here's the code to execute this: class Program { static void Main(string[] args) { BaseClass.Write("Hello World!"); NewClass.Write("Hello World!"); Console.Read(); } } So I would expect the output to be Hello World! > Hello World! But the output is Hello World Hello World I do not understand why this is happening. Here is my thought process as to what is happening: The CLR calls the BaseClass.Write() method The CLR initialises the BaseClass.consoleWriter member. The method is called and executed with the BaseClass.consoleWriter variable Then The CLR calls the NewClass.Write() The CLR initialises the NewClass.consoleWriter object. The CLR sees that the implementation lies in BaseClass, but the method is inherited through The CLR executes the method locally (in NewClass) using the NewClass.consoleWriter variable I thought this is how the inheritance structure works? Please can someone help me understand why this is not working?

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• Set a callback function to a new window in javascript

  - by SztupY

  Is there an easy way to set a "callback" function to a new window that is opened in javascript? I'd like to run a function of the parent from the new window, but I want the parent to be able to set the name of this particular function (so it shouldn't be hardcoded in the new windows page). For example in the parent I have: function DoSomething { alert('Something'); } ... <input type="button" onClick="OpenNewWindow(linktonewwindow,DoSomething);" /> And in the child window I want to: <input type="button" onClick="RunCallbackFunction();" /> The question is how to create this OpenNewWindow and RunCallbackFunction functions. I though about sending the function's name as a query parameter to the new window (where the server side script generates the appropriate function calls in the generated child's HTML), which works, but I was thinking whether there is another, or better way to accomplish this, maybe something that doesn't even require server side tinkering. Pure javascript, server side solutions and jQuery (or other frameworks) are all welcomed.

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• Problems with classes (super new)

  - by user260036

  Hi, I've problems to figure it out what's happening in the following exercise, I'm learning Smalltalk, so I'm newbie. Class Anew ^super new initialize. Ainitialize a:=0. Class Bnew: aParameter |instance| instance := super new. instance b: instance a + aParameter. ^instance Binitialize b:=0. The problem says what happen when the following code is executed: B new:10. But I can't not figure it out why instance variable does not belong to A class. Thanks

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• The C++ 'new' keyword and C

  - by Florian

  In a C header file of a library I'm using one of the variables is named 'new'. Unfortunately, I'm using this library in a C++ project and the occurence of 'new' as a variable names freaks out the compiler. I'm already using extern "C" { #include<... }, but that doesn't seem to help in this respect. Do I have to aks the library developer to change the name of that variable even though from his perspective, as a C developer, the code is absolutely fine, as 'new' is not a C keyword?

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• The Latest Dish

  - by Oracle Staff

  Black Eyed Peas to Headline at Appreciation Event If you're coming to OpenWorld to fill up on the latest in IT solutions, be sure to save room for dessert. At the Oracle OpenWorld Appreciation Event, you'll be savoring the music of the world's hottest funk pop band, Black Eyed Peas, plus superstar rock legends Don Henley, of the Eagles, and Steve Miller. Save the date now: When: Wednesday, September 22, 8 p.m-12 a.m. Where: Treasure Island, San Francisco OpenWorld's annual thank-you event will be our most spectacular yet. Treasure Island, in the center of scenic San Francisco Bay, will once again serve as a rockin' oasis for Oracle customers and partners as they groove to the beat and enjoy delicious food, drinks, and festivities. Get all the details here.

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• "Add to Source Control" option when making a new C# project in VS 2010

  - by Haxed

  When I go to make a new C# Windows application in VS 2010, there is an option at the bottom right area with a check box saying add to source. I want to know what happens, if I check it and create the new C# file.

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• JavaScript: using constructor without operator 'new'

  - by GetFree

  Please help me to understand why the following code works: <script> var re = RegExp('\\ba\\b') ; alert(re.test('a')) ; alert(re.test('ab')) ; </script> In the first line there is no new operator. As far as I know, a contructor in JavaScript is a function that initialize objects created by the operator new and they are not meant to return anything.

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• c++ how to ? function_x ( new object1 )

  - by ismail marmoush

  Hi i want to do the next instead of MyClass object; function_x (object); i want to function_x ( new object ); so what will be the structure of the MyClass to be able to do that .. if i just compiled it , it gives me a compile time error answer function_x (MyClass() ) New Edit thanks for the quick answers.. i did ask the wrong Question i should have asked how temporary variables created in C++ and the answer

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• Why do I need to call new?

  - by cam

  It seems like I could program something without ever using the word 'new', and I would never have to worry about deleting anything either. From what I understand, it's because I would run out of stack memory. Is this correct? I guess my main question is, when should I call 'new'?

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• Behaviour difference Dim oDialog1 as Dialog1 = New Dialog1 VS Dim oDialog1 as Dialog1 = Dialog1

  - by user472722

  VB.Net 2005 I have a now closed Dialog1. To get information from the Dialog1 from within a module I need to use Dim oDialog1 as Dialog1 = New Dialog1. VB.Net 2008 I have a still open Dialog1. To get information from the Dialog1 from within a module I need to use Dim oDialog1 as Dialog1 = Dialog1. VB.Net 2005 does not compile using Dim oDialog1 as Dialog1 = Dialog1 and insists on NEW What is going on and why do I need the different initialisation syntax?

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• What is new for developers in SQL Server 2008 R2

  - by Eduardo Molteni

  Today was released SQL Server 2008 R2. Was trying to find what is new (from the developer perspective), but the MS sites has all the PR blah, blah, blah. There is something new to be aware?

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• Problem adding Contact with new API

  - by Mike

  Hello, I am trying to add a new contact to my contact list using the new ContactContract API via my application. I have the following method based on the Contact Manager example on android dev. private static void addContactCore(Context context, String accountType, String accountName, String name, String phoneNumber, int phoneType) throws RemoteException, OperationApplicationException { ArrayList<ContentProviderOperation> ops = new ArrayList<ContentProviderOperation>(); //Add contact type ops.add(ContentProviderOperation.newInsert(ContactsContract.RawContacts.CONTENT_URI) .withValue(ContactsContract.RawContacts.ACCOUNT_TYPE, accountType) .withValue(ContactsContract.RawContacts.ACCOUNT_NAME, accountName) .build()); //Add contact name ops.add(ContentProviderOperation.newInsert(ContactsContract.Data.CONTENT_URI) .withValueBackReference(ContactsContract.Data.RAW_CONTACT_ID, 0) .withValue(ContactsContract.Data.MIMETYPE, ContactsContract.CommonDataKinds.StructuredName.CONTENT_ITEM_TYPE) .withValue(ContactsContract.CommonDataKinds.StructuredName.DISPLAY_NAME, (!name.toLowerCase().equals("unavailable") && !name.equals("")) ? name : phoneNumber) .build()); //Add phone number ops.add(ContentProviderOperation.newInsert(ContactsContract.Data.CONTENT_URI) .withValueBackReference(ContactsContract.Data.RAW_CONTACT_ID, 0) .withValue(ContactsContract.Data.MIMETYPE, ContactsContract.CommonDataKinds.Phone.CONTENT_ITEM_TYPE) .withValue(ContactsContract.CommonDataKinds.Phone.NUMBER, phoneNumber) .withValue(ContactsContract.CommonDataKinds.Phone.TYPE, phoneType) .build()); //Add contact context.getContentResolver().applyBatch(ContactsContract.AUTHORITY, ops); } In one example I have the flowing values for the parameters. accountType:com.google accountName:(my google account email) name:Mike phoneNumber:5555555555 phoneType:3 The call to the function returns normally without any exception being thrown however the contact is no where to be found in the contact manager on my phone. There is also no contact with that information on my phone already. Does anyone have any insight into what I might be doing wrong?

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• linux new/delete, malloc/free large memory blocks

  - by brian_mk

  Hi folks, We have a linux system (kubuntu 7.10) that runs a number of CORBA Server processes. The server software uses glibc libraries for memory allocation. The linux PC has 4G physical memory. Swap is disabled for speed reasons. Upon receiving a request to process data, one of the server processes allocates a large data buffer (using the standard C++ operator 'new'). The buffer size varies depening upon a number of parameters but is typically around 1.2G Bytes. It can be up to about 1.9G Bytes. When the request has completed, the buffer is released using 'delete'. This works fine for several consecutive requests that allocate buffers of the same size or if the request allocates a smaller size than the previous. The memory appears to be free'd ok - otherwise buffer allocation attempts would eventually fail after just a couple of requests. In any case, we can see the buffer memory being allocated and freed for each request using tools such as KSysGuard etc. The problem arises when a request requires a buffer larger than the previous. In this case, operator 'new' throws an exception. It's as if the memory that has been free'd from the first allocation cannot be re-allocated even though there is sufficient free physical memory available. If I kill and restart the server process after the first operation, then the second request for a larger buffer size succeeds. i.e. killing the process appears to fully release the freed memory back to the system. Can anyone offer an explanation as to what might be going on here? Could it be some kind of fragmentation or mapping table size issue? I am thinking of replacing new/delete with malloc/free and use mallopt to tune the way the memory is being released to the system. BTW - I'm not sure if it's relevant to our problem, but the server uses Pthreads that get created and destroyed on each processing request. Cheers, Brian.

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• Should a new language compiler target the JVM?

  - by Pindatjuh

  I'm developing a new language. My initial target was to compile to native x86 for the Windows platform, but now I am in doubt. I've seen some new languages target the JVM (most notable Scala and Clojure). Ofcourse it's not possible to port every language easily to the JVM; to do so, it may lead to small changes to the language and it's design. So that's the reason behind this doubt, and thus this question: Is targetting the JVM a good idea, when creating a compiler for a new language? Or should I stick with x86? I have experience in generating JVM bytecode. Are there any workarounds to JVM's GC? The language has deterministic implicit memory management. How to produce JIT-compatible bytecode, such that it will get the highest speedup? Is it similar to compiling for IA-32, such as the 4-1-1 muops pattern on Pentium? I can imagine some advantages (please correct me if I'm wrong): JVM bytecode is easier than x86. Like x86 communicates with Windows, JVM communicates with the Java Foundation Classes. To provide I/O, Threading, GUI, etc. Implementing "lightweight"-threads.I've seen a very clever implementation of this at http://www.malhar.net/sriram/kilim/. Most advantages of the Java Runtime (portability, etc.) The disadvantages, as I imagined, are: Less freedom? On x86 it'll be more easy to create low-level constructs, while JVM has a higher level (more abstract) processor. Most disadvantages of the Java Runtime (no native dynamic typing, etc.)

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• safe placement new & explicit destructor call

  - by uray

  this is an example of my codes: ` template <typename T> struct MyStruct { T object; } template <typename T> class MyClass { MyStruct<T>* structPool; size_t structCount; MyClass(size_t count) { this->structCount = count; this->structPool = new MyStruct<T>[count]; for( size_t i=0 ; i<count ; i++ ) { //placement new to call constructor new (&this->structPool[i].object) T(); } } ~MyClass() { for( size_t i=0 ; i<this->structCount ; i++ ) { //explicit destructor call this->structPool[i].object.~T(); } delete[] this->structPool; } } ` my question is, is this a safe way to do? do I make some hidden mistake at some condition? will it work for every type of object (POD and non-POD) ?

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• C++ new memory allocation fragmentation

  - by tamulj

  I was trying to look at the behavior of the new allocator and why it doesn't place data contiguously. My code: struct ci { char c; int i; } template <typename T> void memTest() { T * pLast = new T(); for(int i = 0; i < 20; ++i) { T * pNew = new T(); cout << (pNew - pLast) << " "; pLast = pNew; } } So I ran this with char, int, ci. Most allocations were a fixed length from the last, sometimes there were odd jumps from one available block to another. sizeof(char) : 1 Average Jump: 64 bytes sizeof(int): 4 Average Jump: 16 sizeof(ci): 8 (int has to be placed on a 4 byte align) Average Jump: 9 Can anyone explain why the allocator is fragmenting memory like this? Also why is the jump for char so much larger then ints and a structure that contains both an int and char.

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