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  • C++: static function member shared between threads, can block all?

    - by mhambra
    Hi all, I have a class, which has static function defined to work with C-style extern C { static void callback(foo bar) { } }. // static is defined in header. Three objects (each in separate pthread) are instantiated from this class, each of them has own loop (in class constructor), which can receive the callback. The pointer to function is passed as: x = init_function(h, queue_id, &callback, NULL); while(1) { loop_function(x); } So each thread has the same pointer to &callback. Callback function can block for minutes. Each thread object, excluding the one which got the blocking callback, can call callback again. If the callback function exists only once, then any thread attempting to callback will also block. This would give me an undesired bug, circa is interesting to ask: can anything in C++ become acting this way? Maybe, due to extern { } or some pointer usage?

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  • How to use a function for every C# WinForm instead of pasting .

    - by nXqd
    protected override bool ProcessCmdKey(ref Message msg, Keys keyData) { { if (keyData == Keys.Escape) this.Close(); return base.ProcessCmdKey(ref msg, keyData); } } I discovered this snippet to close windows form by esc. I really want to implement this to every windows form. I try to create a new abstract class which inherit from Form and another windows form will inherit from this one . But it doesn't work this way . abstract class AbsForm: Form { protected override bool ProcessCmdKey(ref Message msg, Keys keyData) { { if (keyData == Keys.Escape) this.Close(); return base.ProcessCmdKey(ref msg, keyData); } } } public partial class HoaDonBanSach : AbsForm { public HoaDonBanSach() { InitializeComponent(); } Thanks for reading this :)

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  • problem in add custom error message in zend_element

    - by user1400
    hello all i created a text element like following code $test = $this->createElement('text', 'test'); $test->setLabel('test:'); $test->addValidator(new Zend_Validate_Int()); $test->addErrorMessages(array('isEmpty'=>'u should enter a number','%value% is not integer')); $shomare->setRequired(true); $this->addElement($test); when i set empty or non integer number to textbox , it show both its own error message , if its empty errormessage="u should enter a number" and when it is not a valid integer it shows '%value% is not integer' thanks

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  • Copy method optimization in compilers

    - by Dženan
    Hi All! I have the following code: void Stack::operator =(Stack &rhs) { //do the actual copying } Stack::Stack(Stack &rhs) //copy-constructor { top=NULL; //initialize this as an empty stack (which it is) *this=rhs; //invoke assignment operator } Stack& Stack::CopyStack() { return *this; //this statement will invoke copy contructor } It is being used like this: unsigned Stack::count() { unsigned c=0; Stack copy=CopyStack(); while (!copy.empty()) { copy.pop(); c++; } return c; } Removing reference symbol from declaration of CopyStack (returning a copy instead of reference) makes no difference in visual studio 2008 (with respect to number of times copying is invoked). I guess it gets optimized away - normally it should first make a copy for the return value, then call assignment operator once more to assign it to variable sc. What is your experience with this sort of optimization in different compilers? Regards, Dženan

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  • C++ String pointers

    - by gnm
    In my previous app I had an object like this: class myType { public: int a; string b; } It had a lot of instances scattered everywhere and passed around to nearly every function. The app was slow. Profiling said that 95% of time is eaten by the string allocator function. I know how to work with the object above, but not how to work with string pointers. class myType { public: int a; string* b; } They told me to use pointers as above. How much faster is it with a string pointer? What is copied when I copy the object? How to the following using the class with the pointer: Access the string value Modify the string value without modifying the one in the object (copy?) General things that change if I use string pointers?

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  • Why does GetExportedValues<T>() no longer work after using the .net 4 final version of MEF?

    - by BigJason
    I have been developing a managed extensibility framework application for the last several months using the community preview. I have been using the GetExportedValues() method and the PartCreationPolicy(CreationPolicy.NonShared) to fake a class factory (since only the silverlight version supports a factory). This was working great until I upgraded the project to use .net 4.0. There is no error, it just doesn't work. So why did this code stop working? The code follows: The factory method: public static IEnumerable<DataActionBase> GetActionsFromDirectory(string PluginsFolder) { IEnumerable<DataActionBase> result = null; var catalog = new DirectoryCatalog(PluginsFolder); var container = new CompositionContainer(catalog: catalog); result = container.GetExportedValues<DataActionBase>(); return result; } Example Export Class: [Export(typeof(DataActionBase))] [PartCreationPolicy(CreationPolicy.NonShared)] public class AnAction : DataActionBase { .... }

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  • Sharing base object with inheritance

    - by max
    I have class Base. I'd like to extend its functionality in a class Derived. I was planning to write: class Derived(Base): def __init__(self, base_arg1, base_arg2, derived_arg1, derived_arg2): super().__init__(base_arg1, base_arg2) # ... def derived_method1(self): # ... Sometimes I already have a Base instance, and I want to create a Derived instance based on it, i.e., a Derived instance that shares the Base object (doesn't re-create it from scratch). I thought I could write a static method to do that: b = Base(arg1, arg2) # very large object, expensive to create or copy d = Derived.from_base(b, derived_arg1, derived_arg2) # reuses existing b object but it seems impossible. Either I'm missing a way to make this work, or (more likely) I'm missing a very big reason why it can't be allowed to work. Can someone explain which one it is? [Of course, if I used composition rather than inheritance, this would all be easy to do. But I was hoping to avoid the delegation of all the Base methods to Derived through __getattr__.]

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  • jquery specific show buttons on hover

    - by bob
    I have an application creating a bunch of divs through a loop. Each div has the class "product" so it looks like <div class="product"> !.....stuff here ....! <div class="show_on_hover">...buttons here... </div> </div> so there are about 12 of these same divs per page. I would like to hover over a specific one and show the specific "show_on_hover" div which is initially set to display:none. $('.product').hover(function() { $(.show_on_hover).show(); }, function () { $(.show_on_hover).hide(); } ); That is what I have so far but it will show ALL of the .show_on_hovers on the page so I am wondering how to get only the specific one you have moused over to show. This effect is seen on youtube when you mouseover any of the comments, and some comment tools pop up. Thanks!

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  • Linking/Combining Type Classes in Haskell

    - by thegravian
    Say I have two type classes defined as follows that are identical in function but different in names: class Monad m where (>>=) :: m a -> (a -> m b) -> m b return :: a -> m a class PhantomMonad p where pbind :: p a -> (a -> p b) -> p b preturn :: a -> p b Is there a way to tie these two classes together so something that is an instance of PhantomMonad will automatically be an instance of Monad, or will instances for each class have to be explicitly written? Any insight would be most appreciated, thanks!

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  • PHP: Accessing an object property with a variable.

    - by Peter
    Let's assume I have an array of object properties I'd like to access: $properties = array('foo', 'bar'); I'd like to loop through the object and access these properties dynamically (specifically, I'm trying to dynamically handle missing JSON elements based on an array of expected elements): foreach ($data as $item) { foreach ($properties as $property) { if (empty($item->{$property})) { // Do something } } } Each $item in $data should have the properties 'foo' and 'bar'. If empty(), I'll handle them. I'm trying to get the loop (in line 3) to access $item-{'foo'} and $item-{'bar'}, but it's not working. Any idea why? Thanks!

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  • User HasOne ActiveToken, HasMany Tokens, how to setup in Rails?

    - by viatropos
    I have two simple models: class User < ActiveRecord::Base has_many :tokens # has_one doesn't work, because Token already stores # foreign id to user... # has_one :active_token, :class_name => "Token" # belongs_to doesn't work because Token belongs to # User already, and they both can't belong to each other # belongs_to :active_token, :class_name => "Token" end class Token < ActiveRecord::Base belongs_to :user end I want to say "User has_one :active_token, :class_name => 'Token'", but I can't because Token already belongs_to User. What I did instead was just manually add similar functionality to the user like so: class User < ActiveRecord::Base has_many :tokens attr_accessor :active_token after_create :save_active_token before_destroy :destroy_active_token # it belongs_to, but you can't have both belongs_to each other... def active_token return nil unless self.active_token_id @active_token ||= Token.find(self.active_token_id) end def active_token=(value) self.active_token_id = value.id @active_token = value end def save_active_token self.active_token.user = self self.active_token.save end def destroy_active_token self.active_token.destroy if self.active_token end end Is there a better way?

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  • Creating a custom categories widget

    - by Scott B
    The code below is an attempt to take the WP_Widget_Categories class and use it as the basis for a custom categories widget based on the default categories widget. I'm getting no output however and the widget is not showing up in the "Available Widgets" listing. What am I doing wrong? <?php /* Plugin Name: My Categories Widget Version: 1.0 */ class MY_Widget_Categories extends WP_Widget { function MY_Widget_Categories() { $widget_ops = array( 'classname' => 'widget_categories', 'description' => __( "A list or dropdown of categories" ) ); $this->WP_Widget('categories', __('Categories'), $widget_ops); } function widget( $args, $instance ) { extract( $args ); $title = apply_filters('widget_title', empty( $instance['title'] ) ? __( 'Categories' ) : $instance['title']); $c = $instance['count'] ? '1' : '0'; $h = $instance['hierarchical'] ? '1' : '0'; $d = $instance['dropdown'] ? '1' : '0'; echo $before_widget; if ( $title ) echo $before_title . $title . $after_title; $cat_args = array('orderby' => 'name', 'show_count' => $c, 'hierarchical' => $h); if ( $d ) { $cat_args['show_option_none'] = __('Select Category'); wp_dropdown_categories(apply_filters('widget_categories_dropdown_args', $cat_args)); ?> <script type='text/javascript'> /* <![CDATA[ */ var dropdown = document.getElementById("cat"); function onCatChange() { if ( dropdown.options[dropdown.selectedIndex].value > 0 ) { location.href = "<?php echo get_option('home'); ?>/?cat="+dropdown.options[dropdown.selectedIndex].value; } } dropdown.onchange = onCatChange; /* ]]> */ </script> <?php } else { ?> <ul> <?php $cat_args['title_li'] = ''; wp_list_categories(apply_filters('widget_categories_args', $cat_args)); ?> </ul> <?php } echo $after_widget; } function update( $new_instance, $old_instance ) { $instance = $old_instance; $instance['title'] = strip_tags($new_instance['title']); $instance['count'] = $new_instance['count'] ? 1 : 0; $instance['hierarchical'] = $new_instance['hierarchical'] ? 1 : 0; $instance['dropdown'] = $new_instance['dropdown'] ? 1 : 0; return $instance; } function form( $instance ) { //Defaults $instance = wp_parse_args( (array) $instance, array( 'title' => '') ); $title = esc_attr( $instance['title'] ); $count = isset($instance['count']) ? (bool) $instance['count'] :false; $hierarchical = isset( $instance['hierarchical'] ) ? (bool) $instance['hierarchical'] : false; $dropdown = isset( $instance['dropdown'] ) ? (bool) $instance['dropdown'] : false; ?> <p><label for="<?php echo $this->get_field_id('title'); ?>"><?php _e( 'Title:' ); ?></label> <input class="widefat" id="<?php echo $this->get_field_id('title'); ?>" name="<?php echo $this->get_field_name('title'); ?>" type="text" value="<?php echo $title; ?>" /></p> <p><input type="checkbox" class="checkbox" id="<?php echo $this->get_field_id('dropdown'); ?>" name="<?php echo $this->get_field_name('dropdown'); ?>"<?php checked( $dropdown ); ?> /> <label for="<?php echo $this->get_field_id('dropdown'); ?>"><?php _e( 'Show as dropdown' ); ?></label><br /> <input type="checkbox" class="checkbox" id="<?php echo $this->get_field_id('count'); ?>" name="<?php echo $this->get_field_name('count'); ?>"<?php checked( $count ); ?> /> <label for="<?php echo $this->get_field_id('count'); ?>"><?php _e( 'Show post counts' ); ?></label><br /> <input type="checkbox" class="checkbox" id="<?php echo $this->get_field_id('hierarchical'); ?>" name="<?php echo $this->get_field_name('hierarchical'); ?>"<?php checked( $hierarchical ); ?> /> <label for="<?php echo $this->get_field_id('hierarchical'); ?>"><?php _e( 'Show hierarchy' ); ?></label></p> <?php } } function my_categories_init() { register_sidebar_widget(__('My Categories Widget'), 'MY_Widget_Categories'); } add_action("plugins_loaded", "my_categories_init"); ?>

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  • Code generation tool, to create C# adapter classes for unit testing?

    - by RyBolt
    I know I wouldn't need this with Typemock, however, with something like MoQ , I need to use the adapter pattern to enable the creation of mocks via interfaces for code I don't control. For example, TcpClient is a .NET class, so I use adapter pattern to enable mocking of this object, b/c I need an interface of that class. I then produce interface ITcpClient, that can then be implemented via a TcpClientAdapter class, which is just plain vanilla adapter pattern implementation. I am looking for a tool to do this automatically (creation of interface and adapter), I would think there is one out there somewhere? (or is everyone just hand coding these)

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  • Should we or should we not check in the classes folder in WEB-INF directory into SVN?

    - by Vatsala
    I use SVN, and am learning how to use it along with eclipse IDE. The first time I add classes to my package, there is no problem, the generated class files get into SVN smoothly. The moment I edit them, I get this message - "WEB-INF/classes" is obstructed. I try the "clean-up" command and the clean up command says "WEB-INF/classes" folder is locked. I use TortoiseSVN as my SVN client. I know why this is happening. It probably because the Eclipse overwrites all the files while generating classes and then causes this - Is it inappropriate to commit the class files into SVN? If not, what should I do to commit these class files smoothly?

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  • NSUserDefaults with in-app Settings bundle

    - by Hema Vasudevan
    I'm in the process of building an app and would prefer to have an in-app specific Settings bundle rather than make it available in the Settings application. I'm using NSUserDefaults class to save and retrieve them but would like to have the same Settings app look and feel. I wanted to use InAppSettingsKit or the llamasettings but don't know how to use the NSUserDefaults class. Those kits tell me how to create a .plist file and use their kits. All I need is use the Settings app look and feel while at the same time use NSUserDefaults class to save and retrieve values. Please help.

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  • INSERT SQL in Java

    - by Pierre
    Hello. I have a Java application and I want to use SQL database. I have a class for my connection : public class SQLConnection{ private static String url = "jdbc:postgresql://localhost:5432/table"; private static String user = "postgres"; private static String passwd = "toto"; private static Connection connect; public static Connection getInstance(){ if(connect == null){ try { connect = DriverManager.getConnection(url, user, passwd); } catch (SQLException e) { JOptionPane.showMessageDialog(null, e.getMessage(), "Connection Error", JOptionPane.ERROR_MESSAGE); } } return connect; } } And now, in another class I succeeded to print my values but when I attempt to insert a value nothing is happening ... Here's my code : try { Statement state = SQLConnection.getInstance().createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY); Statement state2 = SQLConnection.getInstance().createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_UPDATABLE); state2.executeUpdate("INSERT INTO table(field1) VALUES (\"Value\")"); // Here's my problem ResultSet res = state.executeQuery("SELECT * FROM plateau");

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  • How to read the values returned by the Json?

    - by user281180
    I have the following code in my view: <% using (Ajax.BeginForm("JsonCreate", new AjaxOptions { OnComplete = "createCategoryComplete" })) { % Add new category <%=Html.TextBox("CategoryId")% <%=Html.TextBox("Test")% Name: <%= Html.TextBox("Name")% <%= Html.ValidationMessage("Name")% </p> <p> <input type="submit" value="Create" /> </p> </fieldset> </div> <% } % In the controller the code is as follows: [AcceptVerbs(HttpVerbs.Post)] public JsonResult JsonCreate(string Name) { if (ModelState.IsValid) { try { //Return a json object to the javascript return Json(new { CategoryId = 123, Test= "test successful" }); } catch { #region Log errors about the exception //Log error to administrator here #endregion } } //If we got this far, something failed, return an empty json object return Json(new { /* Empty object */ }); } What should be the code in the view for the following function to read the values returned by the Json and update the textboxes for CategoryId and Test? function createCategoryComplete() {....???}

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  • A problem with .NET 2.0 project, using a 3.0 DLL which implements WCF services.

    - by avance70
    I made a client for accessing my WCF services in one project, and all classes that work with services inherit from this class: public abstract class ServiceClient<TServiceClient> : IDisposable where TServiceClient : ICommunicationObject This class is where I do stuff like disposing, logging when the client was called, etc. some common stuff which all service classes would normally do. Everything worked fine, until I got the task to implement this on an old system. I got into a problem when I used this project (DLL) in an other project which cannot reference System.ServiceModel (since it's an old .NET 2.0 software that I still maintain, and upgrading it to 3.0 is out of the question). Here, if I omit where TServiceClient : ICommunicationObject then the project can build, but the ServiceClient cannot use, for example, client.Close() or client.State So, is my only solution to drop the where statement, and rewrite the service classes?

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  • jQueryUI widgets

    - by cf_PhillipSenn
    How do I work with widgets? Here's what I've got so far: <html> <head> <script src="http://www.google.com/jsapi"></script> <script type="text/javascript"> google.load("jquery", "1"); google.load("jqueryui", "1"); </script> </head> <body> <div class="ui-widget"> <div class="ui-widget-header"> header </div> <div class="ui-widget-content"> content </div> </div> </body> </html> I'm trying to make a nice little div with a shaded header.

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  • Objective C - Custom Getter with inheritance

    - by anhdat
    Recently I have worked with Core Data. When I want to set a default value for some fields, I came up with this problem: So I made a simple represent: We have 2 class Parent and Child, in which Child inherit from Parent. // Parent.h @interface Parent : NSObject @property (strong, nonatomic) NSString *lastName; // Child.h @interface Child : Parent In Parent class, I made a custom getter to set a default value when nothing is set: // Parent.h - (NSString *)lastName { if (_lastName) { return _lastName; } else { return @"Parent Default Name"; } } But I cannot make a custom default value for the field "name" which Child inherits from its Parent. // Child.h @implementation Child - (NSString *)lastname { if (super.lastName) { return super.lastName; } else { return @"Child Default Name"; } } Apparently, this method is never called. So my question here is: How can I set a custom getter for the field the Child class inherits from Parent without define an overriding property?

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  • Affine Transforms with Demo App

    - by Dex
    I have a demo app here https://github.com/rdetert/image-transform-test After importing an image, you can pinch, zoom, rotate the image. What I want to do is save out a 640x480 image (landscape mode) that looks identical to the live preview. So if there are 100px bars of empty space on the sides, I need the same empty bars in the final output (scaled appropriately). This is proving to be more difficult than I thought it would be. I can't quite get it to come out right after days of working on it. The magic method that generates the final image is called -(void)generateFinalImage Good luck! ;)

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  • Calling from a parent file in python

    - by Teifion
    I have a file called main.py and a file called classes.py main.py contains the application and what's happening while class.py contains some classes. main.py has the following code main.py import classes def addItem(text): print text myClass = classes.ExampleClass() And then we have classes.py classes.py class ExampleClass (object): def __init__(self): addItem('bob') Surprisingly enough that's not the actual code I am using because I've stripped out anything that'd get in the way of you seeing what I want to do. I want to be able to call a method that's defined in main.py from a class within classes.py. How do I do this? Thanks in advance

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  • How to create a project from existing source in Eclipse and then find it?

    - by Roman
    I have created several .class files. All of them are located in one directory. I used a text editor to write these class files. Now I want to switch to Eclipse. In Eclipse I click File-New-Java Project. Then I select "Create project from existing source". After that I select the directory where all my .class files and click OK. As a result, nothing visible happens. But when I try to do the same, Eclipse tells me that that this project already exist. Where does it exist and how can I access it? By the way, in my "workspace" file nothing new appeared. Is it OK? I though my new Java Project will be there.

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  • Setting custom control properties

    - by Rob
    I though it would be very simple but I can not get it today. I have a user control, with a grid control contained in it. public Unit Width { get { return CustomerGrid.Width; } set { CustomerGrid.Width = value; } } I expose the width property and when I set it in the designer it works at run-time but not design time. What class do I inherit from or method to override to get my controls to function at design time. Note I tried to inherit from WebControl but got the message Make sure that the class defined in this code file matches the 'inherits' attribute, and that it extends the correct base class

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  • how does an object knows about its parent in javascript

    - by alter
    Lets suppose I made a class called Person. var Person = function(fname){this.fname = fname;}; pObj is the object I made from this class. var pObj = new Person('top'); now I add one property to Person class, say lname. Person.prototype.lname = "Thomsom"; now pObj.lname gets me "Thomson". My question is that, when pObj didn't find the property lname in it, how does it know where to look for.

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