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• Multiple "ObjectChangeTracker" getting created, can it be avoided?

  - by user555937

  Hi, We are working on a POC where we have following architecture (MVVM), WPF(Client) + WCF + Model(DataAccess)+ ADO.Net Entity Framework 4.0 (with SQL Server 2008 R2 as DB) All are different projects. In the DataAccess layer we have created different Entity Models(edmx) based on the functionality. The tables under perticular flow are grouped and created different entity models. We are using self tracking entities to and fro to communicate with the WPF client through wcf service. For Single model everything works fine. But when we created a Multiple models then few issues started coming. Mutliple models have few duplicate tables/entities. Two probels are, 1) When we try to access entities from different models mutiple objects "ObjectChangeTracker" are getting created. E.g. CompanyModel(edmx) - Company(Entity) - ObjectChangeTracker, ObjectState ProductModel(edmx) - Customer(Entity) - ObjectChangeTracker1, ObjectState1 OrderModel(edmx) - Oder(Entity) - ObjectChangeTracker2, ObjectState2 Is there any way to avoid this? 2) There are few tables which shared across the Models, E.g. Company(Entity) is used in All above mdoels. During compile time it does not thow any error. But run time It gives error saying "Schema specified is not valid. Errors: The mapping of CLR type to EDM type is ambiguous because multiple CLR types match the EDM type "Company"".. To resolve this, we renamed the entities with some prefix to make them Unique. Is there any other way we can resolve this without changing the name of the entity in the same assembly? Thanks in advance and appreciate if anyone has approach for these issues. Thanks, Kiran

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• Reserve space for initially hidden widget in QVBoxLayout

  - by Skinniest Man

  I am using a QVBoxLayout to arrange a vertical stack of widgets. I want some of them to be initially hidden and only show up when a check box is checked. Here is an example of the code I'm using. MyWidget::MyWidget(QWidget *parent) : QWidget(parent) { QVBoxLayout *layout = new QVBoxLayout(this); QLabel *labelLogTypes = new QLabel(tr("Log Types")); m_checkBoxCsv = new QCheckBox(tr("&Delimited File (CSV)")); m_labelDelimiter = new QLabel(tr("Delimiter:")); m_lineEditDelimiter = new QLineEdit(","); checkBoxCsv_Toggled(m_checkBoxCsv-isChecked()); connect(m_checkBoxCsv, SIGNAL(toggled(bool)), SLOT(checkBoxCsv_Toggled(bool))); QHBoxLayout *layoutDelimitedChar = new QHBoxLayout(); layoutDelimitedChar-addWidget(m_labelDelimiter); layoutDelimitedChar-addWidget(m_lineEditDelimiter); m_checkBoxXml = new QCheckBox(tr("&XML File")); m_checkBoxText = new QCheckBox(tr("Plain &Text File")); // Now that everything is constructed, put it all together // in the main layout. layout-addWidget(labelLogTypes); layout-addWidget(m_checkBoxCsv); layout-addLayout(layoutDelimitedChar); layout-addWidget(m_checkBoxXml); layout-addWidget(m_checkBoxText); layout-addStretch(); } MyWidget::checkBoxCsv_Toggled(bool checked) { m_labelDelimiter-setVisible(checked); m_lineEditDelimiter-setVisible(checked); } I want m_labelDelimiter and m_lineEditDelimiter both to be initially invisible and I want their visibility to toggle with the state of m_checkBoxCsv. This code acheives the functionality I desire, but it doesn't seem to reserve space for the two initially hidden widgets. When I check the checkbox, they become visible, but everything is kind of scrunched to accomodate them. If I leave them initially visible, everything is laid out just the way I would like it. Is there any way to make the QVBoxLayout reserve space for these widgets even if they're initially invisible?

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• What's the best way to communicate the purpose of a string parameter in a public API?

  - by Dave

  According to the guidance published in New Recommendations for Using Strings in Microsoft .NET 2.0, the data in a string may exhibit one of the following types of behavior: A non-linguistic identifier, where bytes match exactly. A non-linguistic identifier, where case is irrelevant, especially a piece of data stored in most Microsoft Windows system services. Culturally-agnostic data, which still is linguistically relevant. Data that requires local linguistic customs. Given that, I'd like to know the best way to communicate which behavior is expected of a string parameter in a public API. I wasn't able to find an answer in the Framework Design Guidelines. Consider the following methods: f(string this_is_a_linguistic_string) g(string this_is_a_symbolic_identifier_so_use_ordinal_compares) Is variable naming and XML documentation the best I can do? Could I use attributes in some way to mark the requirements of the string? Now consider the following case: h(Dictionary<string, object> dictionary) Note that the dictionary instance is created by the caller. How do I communicate that the callee expects the IEqualityComparer<string> object held by the dictionary to perform, for example, a case-insensitive ordinal comparison?

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• Code Analysis Warning CA1004 with generic method

  - by Vaccano

  I have the following generic method: // Load an object from the disk public static T DeserializeObject<T>(String filename) where T : class { XmlSerializer xmlSerializer = new XmlSerializer(typeof(T)); try { TextReader textReader = new StreamReader(filename); var result = (T)xmlSerializer.Deserialize(textReader); textReader.Close(); return result; } catch (FileNotFoundException) { } return null; } When I compile I get the following warning: CA1004 : Microsoft.Design : Consider a design where 'MiscHelpers.DeserializeObject(string)' doesn't require explicit type parameter 'T' in any call to it. I have considered this and I don't know a way to do what it requests with out limiting the types that can be deserialized. I freely admit that I might be missing an easy way to fix this. But if I am not, then is my only recourse to suppress this warning? I have a clean project with no warnings or messages. I would like to keep it that way. I guess I am asking "why this is a warning?" At best this seems like it should be a message. And even that seems a bit much. Either it can or it can't be fixed. If it can't then you are just stuck with the warning with no recourse but suppressing it. Am I wrong?

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• MS Exam 70-536 - How to throw and handle exception from thread?

  - by Max Gontar

  Hello! In MS Exam 70-536 .Net Foundation, Chapter 7 "Threading" in Lesson 1 Creating Threads there is a text: Be aware that because the WorkWithParameter method takes an object, Thread.Start could be called with any object instead of the string it expects. Being careful in choosing your starting method for a thread to deal with unknown types is crucial to good threading code. Instead of blindly casting the method parameter into our string, it is a better practice to test the type of the object, as shown in the following example: ' VB Dim info As String = o as String If info Is Nothing Then Throw InvalidProgramException("Parameter for thread must be a string") End If // C# string info = o as string; if (info == null) { throw InvalidProgramException("Parameter for thread must be a string"); } So, I've tried this but exception is not handled properly (no console exception entry, program is terminated), what is wrong with my code (below)? class Program { static void Main(string[] args) { Thread thread = new Thread(SomeWork); try { thread.Start(null); thread.Join(); } catch (InvalidProgramException ex) { Console.WriteLine(ex.Message); } finally { Console.ReadKey(); } } private static void SomeWork(Object o) { String value = (String)o; if (value == null) { throw new InvalidProgramException("Parameter for "+ "thread must be a string"); } } } Thanks for your time!

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• MMGR Questions, code use and thread-saftey

  - by chadb

  1) Is MMGR thread safe? 2) I was hoping someone could help me understand some code. I am looking at something where a macro is used, but I don't understand the macro. I know it contains a function call and an if check, however, the function is a void function. How does wrapping "(m_setOwner (FILE,_LINE_,FUNCTION),false)" ever change return types? #define someMacro (m_setOwner(__FILE__,__LINE__,__FUNCTION__),false) ? NULL : new ... void m_setOwner(const char *file, const unsigned int line, const char *func); 3) What is the point of the reservoir? 4) On line 770 ("void *operator new(size_t reportedSize)" there is the line "// ANSI says: allocation requests of 0 bytes will still return a valid value" Who/what is ANSI in this context? Do they mean the standards? 5) This is more of C++ standards, but where does "reportedSize" come from for "void *operator new(size_t reportedSize)"? 6) Is this the code that is actually doing the allocation needed? "au-actualAddress = malloc(au-actualSize);"

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• byte + byte = int... why?

  - by Robert C. Cartaino

  Looking at this C# code... byte x = 1; byte y = 2; byte z = x + y; // ERROR: Cannot implicitly convert type 'int' to 'byte' The result of any math performed on byte (or short) types is implicitly cast back to an integer. The solution is to explicitly cast the result back to a byte, so... byte z = (byte)(x + y); // works What I am wondering is why? Is it architectural? Philosophical? We have: int + int = int long + long = long float + float = float double + double = double So why not: byte + byte = byte short + short = short ? A bit of background: I am performing a long list of calculations on "small numbers" (i.e. < 8) and storing the intermediate results in a large array. Using a byte array (instead of an int array) is faster (because of cache hits). But the extensive byte-casts spread through the code make it that much more unreadable.

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• Using static variables for Strings

  - by Vivart

  below content is taken from Best practice: Writing efficient code but i didn't understand why private static String x = "example"; faster than private static final String x ="example"; Can anybody explain this. Using static variables for Strings When you define static fields (also called class fields) of type String, you can increase application speed by using static variables (not final) instead of constants (final). The opposite is true for primitive data types, such as int. For example, you might create a String object as follows: private static final String x = "example"; For this static constant (denoted by the final keyword), each time that you use the constant, a temporary String instance is created. The compiler eliminates "x" and replaces it with the string "example" in the bytecode, so that the BlackBerry® Java® Virtual Machine performs a hash table lookup each time that you reference "x". In contrast, for a static variable (no final keyword), the String is created once. The BlackBerry JVM performs the hash table lookup only when it initializes "x", so access is faster. private static String x = "example"; You can use public constants (that is, final fields), but you must mark variables as private.

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• Conversion between different template instantiation of the same template

  - by Naveen

  I am trying to write an operator which converts between the differnt types of the same implementation. This is the sample code: template <class T = int> class A { public: A() : m_a(0){} template <class U> operator A<U>() { A<U> u; u.m_a = m_a; return u; } private: int m_a; }; int main(void) { A<int> a; A<double> b = a; return 0; } However, it gives the following error for line u.m_a = m_a;. Error 2 error C2248: 'A::m_a' : cannot access private member declared in class 'A' d:\VC++\Vs8Console\Vs8Console\Vs8Console.cpp 30 Vs8Console I understand the error is because A<U> is a totally different type from A<T>. Is there any simple way of solving this (may be using a friend?) other than providing setter and getter methods? I am using Visual studio 2008 if it matters.

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• ant conditions problem

  - by senzacionale

  I have problem with ant. I woul dlike to use conditions in ant. But i get error of: BUILD FAILED C:\Projekti\Projekt ANT\build.xml:412: Problem: failed to create task or type Cause: The name is undefined. Action: Check the spelling. Action: Check that any custom tasks/types have been declared. Action: Check that any / declarations have taken place. and this is code: <target name="test"> <input message="Write some text: " addproperty="foo" /> <if> <equals arg1="${foo}" arg2="bar" /> <then> <echo message="The value of property foo is 'bar'" /> </then> <elseif> <equals arg1="${foo}" arg2="foo" /> <then> <echo message="The value of property foo is 'foo'" /> </then> </elseif> <else> <echo message="The value of property foo is not 'foo' or 'bar'" /> </else> </if> </target>

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• Reflection and Operator Overloads in C#

  - by TenshiNoK

  Here's the deal. I've got a program that will load a given assembly, parse through all Types and their Members and compile a TreeView (very similar to old MSDN site) and then build HTML pages for each node in the TreeView. It basically takes a given assembly and allows the user to create their own MSDN-like library for it for documentation purposes. Here's the problem I've run into: whenever an operator overload is encounted in a defined class, reflection returns that as a "MethodInfo" with the name set to something like "op_Assign" or "op_Equality". I want to be able to capture these and list them properly, but I can't find anything in the MethodInfo object that is returned to accurately identify that I'm looking at an operator. I definitely don't want to just capture everything that starts with "op_", since that will most certainly (at some point) will pick up a method it's not supposed to. I know that other methods and properties that are "special cases" like this one have the "IsSpecialName" property set, but appearantly that's not the case with operators. I've been scouring the 'net and wracking my brain to two days trying to figure this one out, so any help will be greatly appreciated.

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• How do you pass a generic delegate argument to a method in .NET 2.0

  - by Seth Spearman

  Hello, I have a class with a delegate declaration as follows... Public Class MyClass Public Delegate Function Getter(Of TResult)() As TResult 'the following code works. Public Shared Sub MyMethod(ByVal g As Getter(Of Boolean)) 'do stuff End Sub End Class However, I do not want to explicitly type the Getter delegate in the Method call. Why can I not declare the parameter as follows... ... (ByVal g As Getter(Of TResult)) Is there a way to do it? My end goal was to be able to set a delegate for property setters and getters in the called class. But my reading indicates you can't do that. So I put setter and getter methods in that class and then I want the calling class to set the delegate argument and then invoke. Is there a best practice for doing this. I realize in the above example that I can set set the delegate variable from the calling class...but I am trying to create a singleton with tight encapsulation. For the record, I can't use any of the new delegate types declared in .net35. Answers in C# are welcome. Any thoughts? Seth

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• Selectind DOM elements based on attribute content

  - by sameold

  I have several types of <a> in my document. I'd like to select only the <a> whose title attribute begins with the text "more data ..." like <a title="more data *"> For example given the markup below, I'd like to select the first and second <a>, but skip the third because title doesn't begin with more data, and skip the 4th because <a> doesn't even have a title attribute. <a title="more data some text" href="http://mypage.com/page.html">More</a> <a title="more data other text" href="http://mypage.com/page.html">More</a> <a title="not needed" href="http://mypage.com/page.html">Not needed</a> <a href="http://mypage.com/page.html">Not needed</a> I'm using DOMXPath. How would my query look like? $xpath = new DOMXPath($doc); $q = $xpath->query('//a');

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• Applying a function to a custom type in F#

  - by Frederik Wordenskjold

  On my journey to learning F#, I've run into a problem I cant solve. I have defined a custom type: type BinTree = | Node of int * BinTree * BinTree | Empty I have made a function which takes a tree, traverses it, and adds the elements it visits to a list, and returns it: let rec inOrder tree = seq{ match tree with | Node (data, left, right) -> yield! inOrder left yield data; yield! inOrder right | Empty -> () } |> Seq.to_list; Now I want to create a function, similar to this, which takes a tree and a function, traverses it and applies a function to each node, then returns the tree: mapInOrder : ('a -> 'b) -> 'a BinTree -> 'b BinTree This seems easy, and it probably is! But I'm not sure how to return the tree. I've tried this: let rec mapInOrder f tree = match tree with | Node(data, left, right) -> mapInOrder f left Node(f(data), left, right) mapInOrder f right | Empty -> () but this returns a unit. I havent worked with custom types before, so I'm probably missing something there!

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• Jquery.Validate plugin + realPerson plugin

  - by Dave Watts

  I can't figure out how to make it so the form wont fire unless the realPerson captcha is "valid". I can see that when the user types in the correct/valid letters and clicks submit it adds a class of "valid" to the input. So Ive been trying to figure out how to get the jquery.validate plugin to only fire when the class "valid" is present. <script type="text/javascript"> $(document).ready(function(){ $('#defaultReal').realperson(); $('#contact_form2').validate({ submitHandler: function(form) { var str = $("form").serialize(); $.ajax({ type: "POST", url: "contactpage.php", data: str, success: function(){ $('#contact_form2').html("<div id='message'></div>"); $('#message').html("<h2>Contact Form Submitted!</h2>") .append("<p>We will be in touch soon.</p>") .hide() .fadeIn(1500, function() { $('#message').append("<img id='checkmark' src='images/check.png' />"); }); }}); return false; } }); Thank you in advanced! -Dave

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• Catch a PHP Object Instantiation Error

  - by Rob Wilkerson

  It's really irking me that PHP considers the failure to instantiate an object a Fatal Error (which can't be caught) for the application as a whole. I have set of classes that aren't strictly necessary for my application to function--they're really a convenience. I have a factory object that attempts to instantiate the class variant that's indicated in a config file. This mechanism is being deployed for message storage and will support multiple store types: DatabaseMessageStore FileMessageStore MemcachedMessageStore etc. A MessageStoreFactory class will read the application's preference from a config file, instantiate and return an instance of the appropriate class. It might be easy enough to slap a conditional around the instantiation to ensure that class_exists(), but MemcachedMessageStore extends PHP's Memcached class. As a result, the class_exists() test will succeed--though instantiation will fail--if the memcached bindings for PHP aren't installed. Is there any other way to test whether a class can be instantiated properly? If it can't, all I need to do is tell the user which features won't be available to them, but let them continue one with the application. Thanks.

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• Java: Typecasting to Generics

  - by bguiz

  This method that uses method-level generics, that parses the values from a custom POJO, JXlistOfKeyValuePairs (which is exactly that). The only thing is that both the keys and values in JXlistOfKeyValuePairs are Strings. This method wants to taken in, in addition to the JXlistOfKeyValuePairs instance, a Class<T> that defines which data type to convert the values to (assume that only Boolean, Integer and Float are possible). It then outputs a HashMap with the specified type for the values in its entries. This is the code that I have got, and it is obviously broken. private <T extends Object> Map<String, T> fromListOfKeyValuePairs(JXlistOfKeyValuePairs jxval, Class<T> clasz) { Map<String, T> val = new HashMap<String, T>(); List<Entry> jxents = jxval.getEntry(); T value; String str; for (Entry jxent : jxents) { str = jxent.getValue(); value = null; if (clasz.isAssignableFrom(Boolean.class)) { value = (T)(Boolean.parseBoolean(str)); } else if (clasz.isAssignableFrom(Integer.class)) { value = (T)(Integer.parseInt(str)); } else if (clasz.isAssignableFrom(Float.class)) { value = (T)(Float.parseFloat(str)); } else { logger.warn("Unsupported value type encountered in key-value pairs, continuing anyway: " + clasz.getName()); } val.put(jxent.getKey(), value); } return val; } This is the bit that I want to solve: if (clasz.isAssignableFrom(Boolean.class)) { value = (T)(Boolean.parseBoolean(str)); } else if (clasz.isAssignableFrom(Integer.class)) { value = (T)(Integer.parseInt(str)); } I get: Inconvertible types required: T found: Boolean Also, if possible, I would like to be able to do this with more elegant code, avoiding Class#isAssignableFrom. Any suggestions? Sample method invocation: Map<String, Boolean> foo = fromListOfKeyValuePairs(bar, Boolean.class);

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• typeahead.js remote with subset matching

  - by rebelde

  Instead of returning to the server after each additional letter is typed, I want it to only go to the server once, get all matching words, and filter the downloaded data after that. We are having trouble making this work. We are successfully using "remote" to wait until two letters are typed, but we can't get it to stop going to the server as additional letters are typed. Steps: 1. After two letters are typed, retrieve all matching words that start with those two letters. 2. When a third and additional letters are typed, don't go to the server again, just filter from the previous list that was sent. An example: "mo" is typed in. All 100 words that start with "mo" are returned. (Only 10 are shown.) "mor" - now with a third letter, we don't go back to the server. We just find the 20 words that match from within the previous set of words. Can anybody make this work? In real life (using YUI2), we do this and then go back to the server if somebody types in a space after the word. At that point, we know to retrieve additional words. Thanks!

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• Concrete examples of state sharing between multiple viewmodels (WPF MVVM)

  - by JohnMetta

  I have a WPF/Entity Framework (4.0) project with many objects. I'd like to build the application so that that I can have object selection state shared across viewmodels. For Example: We have Cars, Drivers, Passengers, and Cargo classes. We also have UserControls for CarList, DriverList, etc. and editor windows for CarEditor, DriverEditor, etc. Furthermore, we have viewmodels for all of these (CarListViewModel, DriverListViewModel, CargoEditorViewModel, etc). This all composes a dockable interface where the user can have multiple object lists, editors, and viewers open. What I want is a concrete code example of how to wireup multiple viewmodels so that selecting a car in the CarList will cause that car to go live in the CarEditorView, but also be selected in any other view for which the context is valid (such as a DriverByCarView- or just DriverList if there is a filter predicate). There are a number of suggestions and discussions based on this question. The two methods that seem to dominate are: 3018307: Discusses state sharing by mentioning a messaging subsystem 1159035: Discusses state sharing by using an enclosing viewmodel Is one of these approaches better than the other? Does anyone have a concrete example of either/both of these methods in the form of a write-up or small code project? I'm still learning WPF, so pointers to entry points for reading API fundamentals are appreciated, but looking at code examples is where I usually go. Thanks In case anyone is interested, here are some other similar discussions: 3816961: Discusses returning multiple viewmodels depending on object type (i.e. a collection of arbitrary types adhering to a specific interface) 1928130: Discusses whether it is a good idea to aggregate viewmodels as properties of other viewmodels (e.g. a MainWindow viewmodel composed of panel viewmodels) 1120061: Essentially discusses whether to have use a viewmodel-per-model strategy or a viewmodel-per-view-element strategy. 4244222: Discusses whether or not to nest the viewmodels when using a nested object hierarchy. 4429708: Discusses sharing collections between viewmodels directly, but doesn't go into detail. List item: Discusses managing multiple selections within a single viewmodel.

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• C# - Calling ToString() on a Reference Type

  - by nfplee

  Given two object arrays I need to compare the differences between the two (when converted to a string). I've reduced the code to the following and the problem still exists: public void Compare(object[] array1, object[] array2) { for (var i = 0; i < array1.Length; i++) { var value1 = GetStringValue(array1[i]); var value2 = GetStringValue(array2[i]); } } public string GetStringValue(object value) { return value != null && value.ToString() != string.Empty ? value.ToString() : ""; } The code executes fine no matter what object arrays I throw at it. However if one of the items in the array is a reference type then somehow the reference is updated. This causes issues later. It appears that this happens when calling ToString() against the object reference. I have updated the GetStringValue method to the following (which makes sure the object is either a value type or string) and the problem goes away. public string GetStringValue(object value) { return value != null && (value.GetType().IsValueType || value is string) && value.ToString() != string.Empty ? value.ToString() : ""; } However this is just a temporary hack as I'd like to be able to override the ToString() method on my reference types and compare them as well. I'd appreciate it if someone could explain why this is happening and offer a potential solution. Thanks

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• SSE (SIMD extensions) support in gcc

  - by goldenmean

  Hi, I see a code as below: include "stdio.h" #define VECTOR_SIZE 4 typedef float v4sf __attribute__ ((vector_size(sizeof(float)*VECTOR_SIZE))); // vector of four single floats typedef union f4vector { v4sf v; float f[VECTOR_SIZE]; } f4vector; void print_vector (f4vector *v) { printf("%f,%f,%f,%f\n", v->f[0], v->f[1], v->f[2], v->f[3]); } int main() { union f4vector a, b, c; a.v = (v4sf){1.2, 2.3, 3.4, 4.5}; b.v = (v4sf){5., 6., 7., 8.}; c.v = a.v + b.v; print_vector(&a); print_vector(&b); print_vector(&c); } This code builds fine and works expectedly using gcc (it's inbuild SSE / MMX extensions and vector data types. this code is doing a SIMD vector addition using 4 single floats. I want to understand in detail what does each keyword/function call on this typedef line means and does: typedef float v4sf __attribute__ ((vector_size(sizeof(float)*VECTOR_SIZE))); What is the vector_size() function return; What is the __attribute__ keyword for Here is the float data type being type defined to vfsf type? I understand the rest part. thanks, -AD

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• I'm annoyed with asp .net mvc action links? Is there something better in MVC3?

  - by Jonathon Kresner

  After almost 3 years with mvc I'm scratching my head. Is it just me, or does the way we specify links in asp .net mvc suck? @Html.ActionLink("Log Off", "LogOff", "Account") In the previews for mvc 1 we had the funky generic action links which gave us intellisense and compile checking, which I LOVED. I know they removed them because of performance issues and because you could not actually guarantee that the route would resolve all the time... However the default way of doing it just doesn't make me feel safe enough in a big application. I've also used T4Mvc with MVC2, to be honest, I didn't really like it. It's not part of the Mvc framework and frustrating to develop with especially with source control in big teams and continuous integration builds. I guess I could also import Mvc Futures and keep using the generic types (it's probably what I'll do). I'm just about to start a very big project and was wondering what other people are thinking? Is anyone else annoyed with the options or has a new solution? It seems like ActionLinks are the most basic & frequently used feature. Shouldn't there be a good out of the box solution, we're just about to hit revision 3 of this framework.

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• Quick and easy flood protection?

  - by James P

  I have a site where a user submits a message using AJAX to a file called like.php. In this file the users message is submitted to a database and it then sends a link back to the user. In my Javascript code I disabled the text box the user types into when they submit the AJAX request. The only problem is, a malicious user can just constantly send POST requests to like.php and flood my database. So I would like to implement simple flood protection. I don't really want the hassle of another database table logging users IPs and such... as if they are flooding my site there will be a lot of database read/writes slowing it down. I thought about using sessions, like have a session that contains a timestamp that gets checked every time they send data to like.php, and if the current time is before the timestamp let them add data to the database, otherwise send out an error and block them. If they are allowed to enter something into the database, update their session with a new timestamp. What do you think? Would this be the best way to go about it or are there easier alternatives? Thanks for any help. :)

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• Computation overhead in C# - Using getters/setters vs. modifying arrays directly and casting speeds

  - by Jeffrey Kern

  I was going to write a long-winded post, but I'll boil it down here: I'm trying to emulate the graphical old-school style of the NES via XNA. However, my FPS is SLOW, trying to modify 65K pixels per frame. If I just loop through all 65K pixels and set them to some arbitrary color, I get 64FPS. The code I made to look-up what colors should be placed where, I get 1FPS. I think it is because of my object-orented code. Right now, I have things divided into about six classes, with getters/setters. I'm guessing that I'm at least calling 360K getters per frame, which I think is a lot of overhead. Each class contains either/and-or 1D or 2D arrays containing custom enumerations, int, Color, or Vector2D, bytes. What if I combined all of the classes into just one, and accessed the contents of each array directly? The code would look a mess, and ditch the concepts of object-oriented coding, but the speed might be much faster. I'm also not concerned about access violations, as any attempts to get/set the data in the arrays will done in blocks. E.g., all writing to arrays will take place before any data is accessed from them. As for casting, I stated that I'm using custom enumerations, int, Color, and Vector2D, bytes. Which data types are fastest to use and access in the .net Framework, XNA, XBox, C#? I think that constant casting might be a cause of slowdown here. Also, instead of using math to figure out which indexes data should be placed in, I've used precomputed lookup tables so I don't have to use constant multiplication, addition, subtraction, division per frame. :)

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• Client-Side caching on IIS7 doesn't seem to work

  - by thomasbtv

  I have set content caching on a specific folder by following the local web.config method. I don't think it works, and I would like to fix this. I activate the cache using the IIS / HTTP Headers / Common headers feature. I set them to 1 day of expiration. I opened a page with Google Chrome in private navigation, and then open the Network tab in the console. The first time I load the page, everything loads from the site, obviously. If I refresh the page, I see 2 types of loading in the Network console: the files from Google and Facebook and such have a status of 200, and a size of (from cache). the files from the folder for which I set the caching have a status of 304 and their size is displayed. So, I guess the caching setting doesn't work? Or does the 304 response means that it's loaded from the cache? If they aren't, how can I make it work ? Thanks !

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