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  • c++ use of winmain()

    - by Jack
    Hi, I just started learning programming for windows in c++. I had this crazy image, that win32 programming is based on calling windows functions and sending parameters to and from them. Like, when you want to create window, you call some win32 function that handles windows GUI and say "Hi, please, create me new window, 100 x 100 px, with two buttons", and that GUI function says "Hi, no problem, when something happends, like user clicks one button, I will change this variable xy located in this location". So, I thought that it will be very similiar to console programming. But the very first instruction surprised me. I always thought that every program executes main() function first. So, when I launch app, windows stores some parameters on top of stack and run that application. So I assumed that initializing main() is just a c++ way to tell the compiler where the first instruction should be. But in win32 programming, there is function called winmain() which starts first. So I am little confused. I thought it´s rule that compiler must have main() to start with, that main just defines where ti start, like some start point identifier. So, please, why is there winmain() function instead of main()? When I thought that C++ programming is as logical as assembler, it confuses me once again.

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  • Delphi TRttiType.GetMethods return zero TRttiMethod instances

    - by conciliator
    I've recently been able to fetch a TRttiType for an interface using TRttiContext.FindType using Robert Loves "GetType"-workaround ("registering" the interface by an explicit call to ctx.GetType, e.g. RType := ctx.GetType(TypeInfo(IMyPrettyLittleInterface));). One logical next step would be to iterate the methods of said interface. Consider program rtti_sb_1; {$APPTYPE CONSOLE} uses SysUtils, Rtti, mynamespace in 'mynamespace.pas'; var ctx: TRttiContext; RType: TRttiType; Method: TRttiMethod; begin ctx := TRttiContext.Create; RType := ctx.GetType(TypeInfo(IMyPrettyLittleInterface)); if RType <> nil then begin for Method in RType.GetMethods do WriteLn(Method.Name); end; ReadLn; end. This time, my mynamespace.pas looks like this: IMyPrettyLittleInterface = interface ['{6F89487E-5BB7-42FC-A760-38DA2329E0C5}'] procedure SomeProcedure; end; Unfortunately, RType.GetMethods returns a zero-length TArray-instance. Are there anyone able to reproduce my troubles? (Note that in my example I've explicitly fetched the TRttiType using TRttiContext.GetType, not the workaround; the introduction is included to warn readers that there might be some unresolved issues regarding rtti and interfaces.) Thanks!

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  • Distinct or group by on some columns but not others

    - by Nazadus
    I have a view that I'm trying to filter with something similar to DISTINCT on some columns but not others. I have a view like this: Name LastName Zip Street1 HouseholdID (may not be unique because it may have multiple addresses -- think of it in the logical sense as grouping persons but not physical locations; If you lookup HouseholdID 4130, you may get two rows.. or more, because the person may have mutiple mailing locations) City State I need to pull all those columns but filter on LastName,Zip, and Street1. Here's the fun part: The filter is arbitrary -- meaning I don't care which one of the duplicates goes away. This is for a mail out type thing and the other information is not used for any other reason than than to look up a specific person if needed (I have no idea why). So.. given one of the records, you can easily figure out the removed ones. As it stands now, my Sql-Fu fails me and I'm filtering in C# which is incredibly slow and is pretty much a foreach that starts with an empty list and adds the row in if the combined last name, zip, and street aren't are not in the list. I feel like I'm missing a simple / basic part of SQL that I should be understanding.

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  • How Would a Newborn Baby Learn Web Programming?

    - by Mugatu
    Hello all, I chose that title because I equate my knowledge of web programming and web development with that of a newborn. Here's the shortest version of my story and what I'm looking to do: A friend and I have been coming up with website ideas for a couple years, mostly just jotting them down whenever we come up with a good, useful idea when browsing the web. For the past 6 months we've hired a couple different programmers to make a couple of the sites for us, but have been disappointed with how it's gone. Been too slow and too many miscommunications for our liking. So like the saying goes if you want something done right do it yourself, we're going to do it ourselves. I know nothing about programming, I've never written a line of code in my life. I consider myself very good with math and about as logical as you can get, but I have zero real-life programming knowledge. The sites we want to make are all pretty 'Web 2.0'ish', meaning user-generated content, commenting on posts, pages that change on the fly, etc. So here are some of my questions for anyone who's been there before: Is there a language you'd recommend learning first? Something that is a good indicator how most other languages work? What web programming languages do you recommend learning first based on popularity both now and the future. I don't want to learn a language that's going to be outdated by the time I'm an expert at it. Any specific books you'd recommend? Any general advice you'd give to someone literally starting at square zero for coding who plans on being in it for the long haul? Thanks in advance for the help

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  • problem in working with thread

    - by Xaver
    Ihave the tree view in which i have file system of logical disk. When user select some files and folders and press button programm evaluate the size of selected files and folders. this function may takes a long time. i decide do thread which will run this function. This function works with array of TreeNode. but then i want to now was it node expaned or not compiler say: "attempt to access control "treeview1" not from the thread, in which it was created." Why it appeared? Next code is show how i create array of Nodes which i send to new thread: void frmMain::FillSelected(TreeNode^ a, array<TreeNode^>^ *Paths) { if (a->Parent == nullptr) { for(int j = 0;j < a->Nodes->Count;j++) { if ((a->Nodes[j]->ImageIndex == 1)&&(a->Nodes[j]->Checked==true)) { (*Paths)->Resize((*Paths), (*Paths)->Length + 1); (*Paths)[(*Paths)->Length-1] = a->Nodes[j]; } } } for(int i = 0;i < a->Nodes->Count;i++) { if (a->Parent == nullptr) { FillSelected(a->Nodes[i], Paths); } else { if(a->Nodes[i]->Checked == true) { (*Paths)->Resize((*Paths), (*Paths)->Length + 1); (*Paths)[(*Paths)->Length-1] = a->Nodes[i]; } if ((a->Nodes[i]->Nodes->Count > 0)&&(a->Nodes[i]->Nodes[0]->FullPath != (a->Nodes[i]->FullPath + "\\"))) { FillSelected(a->Nodes[i], Paths); } } } return; }

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  • Very strange Application.ThreadException behaviour.

    - by Brann
    I'm using the Application.ThreadException event to handle and log unexpected exceptions in my winforms application. Now, somewhere in my application, I've got the following code (or rather something equivalent, but this dummy code is enough to reproduce my issue) : try { throw new NullReferenceException("test"); } catch (Exception ex) { throw new Exception("test2", ex); } I'm clearly expecting my Application_ThreadException handler to be passed the "test2" exception, but this is not always the case. Typically, if another thread marshals my code to the UI, my handler receives the "test" exception, exactly as if I hadn't caught "test" at all. Here is a short sample reproducing this behavior. I have omitted the designer's code. static class Program { [STAThread] static void Main() { Application.ThreadException += new System.Threading.ThreadExceptionEventHandler(Application_ThreadException); Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Application.Run(new Form1()); } static void Application_ThreadException(object sender, System.Threading.ThreadExceptionEventArgs e) { Console.WriteLine(e.Exception.Message); } } public partial class Form1 : Form { public Form1() { InitializeComponent(); button1.Click+=new EventHandler(button1_Click); System.Threading.Thread t = new System.Threading.Thread(new System.Threading.ThreadStart(ThrowEx)); t.Start(); } private void button1_Click(object sender, EventArgs e) { try { throw new NullReferenceException("test"); } catch (Exception ex) { throw new Exception("test2", ex); } } void ThrowEx() { this.BeginInvoke(new EventHandler(button1_Click)); } } The output of this program on my computer is : test ... here I click button1 test2 I've reproduced this on .net 2.0,3.5 and 4.0. Does someone have a logical explanation ?

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  • Parse a CSV file using python (to make a decision tree later)

    - by Margaret
    First off, full disclosure: This is going towards a uni assignment, so I don't want to receive code. :). I'm more looking for approaches; I'm very new to python, having read a book but not yet written any code. The entire task is to import the contents of a CSV file, create a decision tree from the contents of the CSV file (using the ID3 algorithm), and then parse a second CSV file to run against the tree. There's a big (understandable) preference to have it capable of dealing with different CSV files (I asked if we were allowed to hard code the column names, mostly to eliminate it as a possibility, and the answer was no). The CSV files are in a fairly standard format; the header row is marked with a # then the column names are displayed, and every row after that is a simple series of values. Example: # Column1, Column2, Column3, Column4 Value01, Value02, Value03, Value04 Value11, Value12, Value13, Value14 At the moment, I'm trying to work out the first part: parsing the CSV. To make the decisions for the decision tree, a dictionary structure seems like it's going to be the most logical; so I was thinking of doing something along these lines: Read in each line, character by character If the character is not a comma or a space Append character to temporary string If the character is a comma Append the temporary string to a list Empty string Once a line has been read Create a dictionary using the header row as the key (somehow!) Append that dictionary to a list However, if I do things that way, I'm not sure how to make a mapping between the keys and the values. I'm also wondering whether there is some way to perform an action on every dictionary in a list, since I'll need to be doing things to the effect of "Everyone return their values for columns Column1 and Column4, so I can count up who has what!" - I assume that there is some mechanism, but I don't think I know how to do it. Is a dictionary the best way to do it? Would I be better off doing things using some other data structure? If so, what?

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  • MyContainer derived from FrameworkElement with binding support.

    - by alex2k8
    To understand how the binding works, I implemented MyContainer derived from FrameworkElement. This container allowes to set Children and adds them into the logical tree. But the binding by ElementName does not work. What can I do with MyContainer to make it work, leaving the parent as FrameworkElement? C#: public class MyContainer : FrameworkElement { public MyContainer() { Children = new List<FrameworkElement>(); } public List<FrameworkElement> Children { get; set; } protected override IEnumerator LogicalChildren { get { return Children.GetEnumerator(); } } } XAML: <Window x:Class="WpfLogicalTree.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:WpfLogicalTree" Title="Window1" Height="300" Width="300"> <StackPanel> <local:MyContainer> <local:MyContainer.Children> <TextBlock Text="Foo" x:Name="_source" /> <TextBlock Text="{Binding Path=Text, ElementName=_source}" x:Name="_target"/> </local:MyContainer.Children> </local:MyContainer> <Button Click="Button_Click">Test</Button> </StackPanel> </Window> Window1.cs private void Button_Click(object sender, RoutedEventArgs e) { MessageBox.Show(_target.Text); }

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  • What makes an effective UI for displaying versioning of structured hierarchical data

    - by Fadrian Sudaman
    Traditional version control system are displaying versioning information by grouping Projects-Folders-Files with Tree view on the left and details view on the right, then you will click on each item to look at revision history for that configuration history. Assuming that I have all the historical versioning information available for a project from Object-oriented model perspective (e.g. classes - methods - parameters and etc), what do you think will be the most effective way to present such information in UI so that you can easily navigate and access the snapshot view of the project and also the historical versioning information? Put yourself in the position that you are using a tool like this everyday in your job like you are currently using SVN, SS, Perforce or any VCS system, what will contribute to the usability, productivity and effectiveness of the tool. I personally find the classical way for display folders and files like above are very restrictive and less effective for displaying deep nested logical models. Assuming that this is a greenfield project and not restricted by specific technology, how do you think I should best approach this? I am looking for idea and input here to add values to my research project. Feel free to make any suggestions that you think is valuable. Thanks again for anyone that shares their thoughts.

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  • Retriving data from ListView control

    - by Josh
    I have a ListView control set up in details mode with 5 columns. It is populated by code using the following subroutine: For j = 0 To 14 cmd = New OleDbCommand("SELECT TeacherName, ClassSubject, BookingDate, BookingPeriod FROM " & SchemaTable.Rows(i)!TABLE_NAME.ToString() & " WHERE (((BookingDate)=" & Chr(34) & Date.Today.AddDays(j) & Chr(34) & ") AND ((UserName)=" & Chr(34) & user & Chr(34) & "));", cn) dr = cmd.ExecuteReader Dim itm As ListViewItem Dim itms(4) As String While dr.Read() itms(0) = dr(0) itms(1) = SchemaTable.Rows(i)!TABLE_NAME.ToString() itms(2) = dr(1) itms(3) = dr(2) itms(4) = dr(3) itm = New ListViewItem(itms) Manage.ManageList.Items.Add(itm) End While Next Note that this is not the full routine, just the bit that populated the grid. Now I need to retrieve data from the ListView control in order to delete a booking in my database. I used the following code to retrieve the content of each column: ManageList.SelectedItems(0).Text But it only seems to work on index 0. If I do: ManageList.SelectedItems(3).Text I get this error: InvalidArgument=Value of '3' is not valid for 'index'. Parameter name: index I'm pretty much stumped, it seems logical to me that index 1 will point to the 2nd column, index 2 to the 3rd etc, as it's 0 based? Any help would be appreciated, thanks.

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  • What is your personal approach/take on commenting?

    - by Trae
    Duplicate What are your hard rules about commenting? A Developer I work with had some things to say about commenting that were interesting to me (see below). What is your personal approach/take on commenting? "I don't add comments to code unless its a simple heading or there's a platform-bug or a necessary work-around that isn't obvious. Code can change and comments may become misleading. Code should be self-documenting in its use of descriptive names and its logical organization - and its solutions should be the cleanest/simplest way to perform a given task. If a programmer can't tell what a program does by only reading the code, then he's not ready to alter it. Commenting tends to be a crutch for writing something complex or non-obvious - my goal is to always write clean and simple code." "I think there a few camps when it comes to commenting, the enterprisey-type who think they're writing an API and some grand code-library that will be used for generations to come, the craftsman-like programmer that thinks code says what it does clearer than a comment could, and novices that write verbose/unclear code so as to need to leave notes to themselves as to why they did something."

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  • How can someone with no experience learn how to program?

    - by Mugatu
    A friend and I have been coming up with website ideas for a couple years, mostly just jotting them down whenever we come up with a good, useful idea when browsing the web. For the past 6 months we've hired a couple different programmers to make a couple of the sites for us, but have been disappointed with how it's gone. Been too slow and too many miscommunications for our liking. So like the saying goes if you want something done right do it yourself, we're going to do it ourselves. I know nothing about programming, I've never written a line of code in my life. I consider myself very good with math and about as logical as you can get, but I have zero real-life programming knowledge. The sites we want to make are all pretty 'Web 2.0'ish', meaning user-generated content, commenting on posts, pages that change on the fly, etc. So here are some of my questions for anyone who's been there before: Is there a language you'd recommend learning first? Something that is a good indicator how most other languages work? What web programming languages do you recommend learning first based on popularity both now and the future. I don't want to learn a language that's going to be outdated by the time I'm an expert at it. Any specific books you'd recommend? Any general advice you'd give to someone literally starting at square zero for coding who plans on being in it for the long haul?

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  • How can I refactor this to work without breaking the pattern horribly?

    - by SnOrfus
    I've got a base class object that is used for filtering. It's a template method object that looks something like this. public class Filter { public void Process(User u, GeoRegion r, int countNeeded) { List<account> selected = this.Select(u, r, countNeeded); // 1 List<account> filtered = this.Filter(selected, u, r, countNeeded); // 2 if (filtered.Count > 0) { /* do businessy stuff */ } // 3 if (filtered.Count < countNeeded) this.SendToSuccessor(u, r, countNeeded - filtered) // 4 } } Select(...), Filter(...) are protected abstract methods and implemented by the derived classes. Select(...) finds objects in the based on x criteria, Filter(...) filters those selected further. If the remaining filtered collection has more than 1 object in it, we do some business stuff with it (unimportant to the problem here). SendToSuccessor(...) is called if there weren't enough objects found after filtering (it's a composite where the next class in succession will also be derived from Filter but have different filtering criteria) All has been ok, but now I'm building another set of filters, which I was going to subclass from this. The filters I'm building however would require different params and I don't want to just implement those methods and not use the params or just add to the param list the ones I need and have them not used in the existing filters. They still perform the same logical process though. I also don't want to complicated the consumer code for this (which looks like this) Filter f = new Filter1(); Filter f2 = new Filter2(); Filter f3 = new Filter3(); f.Sucessor = f2; f2.Sucessor = f3; /* and so on adding filters as successors to previous ones */ foreach (User u in users) { foreach (GeoRegion r in regions) { f.Process(u, r, ##); } } How should I go about it?

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  • WYSIWYG with Qt - font size woes

    - by Rob
    I am creating a custom Qt widget that mimics an A4 printed page and am having problems getting fonts to render at the correct size. My widget uses QPainter::setViewport and QPainter::setWindow to mimic the A4 page, using units of 10ths of a millimetre which enables me to draw easily. However, attempting to create a font at a specific point size doesn't seem to work and using QFont:setPixelSize isn't accurate. Here is some code: View::View(QWidget *parent) : QWidget(parent), printer(new QPrinter) { printer->setPaperSize(QPrinter::A4); printer->setFullPage(true); } void View::paintEvent(QPaintEvent*) { QPainter painter(this); painter.setWindow(0, 0, 2100, 2970); painter.setViewport(0, 0, printer->width(), printer->height()); // Draw a rect at x = 1cm, y = 1cm, 6cm wide and 1 inch high painter.drawRect(100, 100, 600, 254); // Create a 72pt (1 inch) high font QFont font("Arial"); font.setPixelSize(254); painter.setFont(font); // Draw in the same box // The font is too large painter.drawText(QRect(100, 100, 600, 254), tr("Wg\u0102")); // Ack - the actual font size reported by the metrics is 283 pixels! const QFontMetrics fontMetrics = painter.fontMetrics(); qDebug() << "Font height = " << fontMetrics.height(); } So I'm asking for a 254 high font (1 inch, 72 pts) and it's too big and sure enough when I query for the font height via QFontMetrics it is 283 high. Does anyone else know how to use font sizes in points when using custom mapping modes like this? It must be possible. Note that I cannot see how to convert between logical/device points either (i.e. the Win32 DPtoLP/LPtoDP equivalents.)

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  • What does it mean for an OS to "execute within user processes"? Do any modern OS's use that approach

    - by Chris Cooper
    I have recently become interested in operating system, and a friend of mine lent me a book called Operating Systems: Internals and Design Principles (I have the third edition), published in 1998. It's been a very interesting book so far, but I have come to the part dealing with process control, and it's using UNIX System V as one of its examples of an operating system that executes within user processes. This concept has struck me as a little strange. First of all, does this mean that OS instructions and data are stored in each user of the processes? Probably not, because that would be an absurdly redundant scheme. But if not, then what does it mean to "execute within" a user process? Do any modern operating systems use this approach? It seems much more logical to have the operating system execute as its own process, or even independently of all processes, if you're short on memory. All the inter-accessiblilty of process data required for this layout seems to greatly complicate things. (But maybe that's just because I don't quite get the concept ;D) Here is what the book says: "Execution within User Processes: An alternative that is common with operation systems on smaller machines is to execute virtually all operating system software in the context of a user process. ... "

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  • Error in bisection method code in Matlab

    - by Amanda Collins
    I need to write a proper implementation of the bisection method, which means I must address all possible user input errors. Here is my code: function [x_sol, f_at_x_sol, N_iterations] = bisection(f, xn, xp, eps_f, eps_x) % solving f(x)=0 with bisection method % f is the function handle to the desired function, % xn and xp are borders of search, % f(xn)<0 and f(xp)>0 required, % eps_f defines how close f(x) should be to zero, % eps_x defines uncertainty of solution x if(f(xp) < 0) error('xp must be positive') end; if(f(xn)>0) error('xn must be negative') end; if (xn >= xp) error ('xn must be less than xp') end; xg=(xp+xn)/2; %initial guess fg=f(xg); % initial function evaluation N_iterations=1; while ( (abs(fg) > eps_f) & (abs(xg-xp) > eps_x) ) if (fg>0) xp=xg; else xn=xg; end xg=(xp+xn)/2; %update guess fg=f(xg); %update function evaluation N_iterations=N_iterations+1; end x_sol=xg; %solution is ready f_at_x_sol=fg; if (f_at_x_sol > eps_f) error('No convergence') end and here is the error message I receive when I try to test this in Matlab: >> bisection(x.^2, 2, -1, 1e-8, 1e-10) Attempted to access f(-1); index must be a positive integer or logical. Error in bisection (line 9) if(f(xp)<0) I was attempting to see if my error codes worked, but it doesn't look like they do. I get the same error when I try to test it on a function that should work.

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  • Better code for accessing fields in a matlab structure array?

    - by John
    I have a matlab structure array Modles1 of size (1x180) that has fields a, b, c, ..., z. I want to understand how many distinct values there are in each of the fields. i.e. max(grp2idx([foo(:).a])) The above works if the field a is a double. {foo(:).a} needs to be used in the case where the field a is a string/char. Here's my current code for doing this. I hate having to use the eval, and what is essentially a switch statement. Is there a better way? names = fieldnames(Models1); for ix = 1 : numel(names) className = eval(['class(Models1(1).',names{ix},')']); if strcmp('double', className) || strcmp('logical',className) eval([' values = [Models1(:).',names{ix},'];']); elseif strcmp('char', className) eval([' values = {Models1(:).',names{ix},'};']); else disp(['Unrecognized class: ', className]); end % this line requires the statistics toolbox. [g, gn, gl] = grp2idx(values); fprintf('%30s : %4d\n',names{ix},max(g)); end

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  • What would you write in a Constitution (law book) for a programmers' country? [closed]

    - by Developer Art
    After we have got our great place to talk about professional matters and sozialize online - on SO, I believe the next logical step would be to found our own country! I invite you all to participate and bring together your available resources. We will buy an island, better even a group of islands so that we could establish states like .NET territories, Java land, Linux republic etc. We will build a society of programmers (girls - we need you too). To the organizational side, we're going to need some sort of a Constitution or a law book. I suggest we write it together. I make it a wiki as it should be a cooperative effort. I'll open the work. Section 1. Programmers' rights. Every citizen has a right to an Internet connection 24/7. Every citizen can freely choose the field of interest Section 2. Programmers' obligations. Every citizen must embrace the changing nature of the profession and constanly educate himself Section 3. Law enforcement. Code duplication when can be avoided is punished by limiting the bandwith speed to 64Kbit for a period of one week. Using ugly hacks instead of refactoring code is punished by cutting the Internet connection for a period of one month. Usage of technologies older than 5/10 years is punished by restricting the web access to the sites last updated 5/10 years ago for a period of one month. Please feel free to modify and extend the list. We'll need to have it ready before we proceed formally with the country foundation. A purchase fund will be established shortly. Everyone is invited to participate.

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  • Python: Does one of these examples waste more memory?

    - by orokusaki
    In a Django view function which uses manual transaction committing, I have: context = RequestContext(request, data) transaction.commit() return render_to_response('basic.html', data, context) # Returns a Django ``HttpResponse`` object which is similar to a dictionary. I think it is a better idea to do this: context = RequestContext(request, data) response = render_to_response('basic.html', data, context) transaction.commit() return response If the page isn't rendered correctly in the second version, the transaction is rolled back. This seems like the logical way of doing it albeit there won't likely be many exceptions at that point in the function when the application is in production. But... I fear that this might cost more and this will be replete through a number of functions since the application is heavy with custom transaction handling, so now is the time to figure out. If the HttpResponse instance is in memory already (at the point of render_to_response()), then what does another reference cost? When the function ends, doesn't the reference (response variable) go away so that when Django is done converting the HttpResponse into a string for output Python can immediately garbage collect it? Is there any reason I would want to use the first version (other than "It's 1 less line of code.")?

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  • Issue with GCD and too many threads

    - by dariaa
    I have an image loader class which provided with NSURL loads and image from the web and executes completion block. Code is actually quite simple - (void)downloadImageWithURL:(NSString *)URLString completion:(BELoadImageCompletionBlock)completion { dispatch_async(_queue, ^{ // dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{ UIImage *image = nil; NSURL *URL = [NSURL URLWithString:URLString]; if (URL) { image = [UIImage imageWithData:[NSData dataWithContentsOfURL:URL]]; } dispatch_async(dispatch_get_main_queue(), ^{ completion(image, URLString); }); }); } When I replace dispatch_async(_queue, ^{ with commented out dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{ Images are loading much faster, wich is quite logical (before that images would be loaded one at a time, now a bunch of them are loading simultaneously). My issue is that I have perhaps 50 images and I call downloadImageWithURL:completion: method for all of them and when I use global queue instead of _queue my app eventually crashes and I see there are 85+ threads. Can the problem be that my calling dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0) 50 times in a row makes GCD create too many threads? I thought that gcd handles all the treading and makes sure the number of threads is not huge, but if it's not the case is there any way I can influence number of threads?

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  • Silverlight vs Flex

    - by 1kevgriff
    My company develops several types of applications. A lot of our business comes from doing multimedia-type apps, typically done in Flash. However, now that side of the house is starting to migrate towards doing Flex development. Most of our other development is done using .NET. I'm trying to make a push towards doing Silverlight development instead, since it would take better advantage of the .NET developers on staff. I prefer the Silverlight platform over the Flex platform for the simple fact that Silverlight is all .NET code. We have more .NET developers on staff than Flash/Flex developers, and most of our Flash/Flex developers are graphic artists (not real programmers). Only reason they push towards Flex right now is because it seems like the logical step from Flash. I've done development using both, and I honestly believe Silverlight is easier to work with. But I'm trying to convince people who are only Flash developers. So here's my question: If I'm going to go into a meeting to praise Silverlight, why would a company want to go with Silverlight instead of Flex? Other than the obvious "not everyone has Silverlight", what are the pros and cons for each?

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  • How do i return a template class from a template function?

    - by LoudNPossiblyRight
    It looks logical but for some reason when i uncomment the last cout line, this code does not compile. How do i return a template class? What do i have to do to this code to make it work? #include<iostream> using namespace std; template <int x> class someclass{ public: int size; int intarr[x]; someclass():size(x){} }; template<int x, int y> int somefunc(someclass<x> A, someclass<y> B){ return ( A.size > B.size ? A.size : B.size); } template<int x, int y, int z> someclass<x> anotherfunc(someclass<y> A, someclass<z> B){ return ( A.size > B.size ? A : B); } int main(){ someclass<5> A; someclass<10> B; cout << "SIZE = " << somefunc(A,B) << endl; //cout << "SIZE = " << (anotherfunc(A,B)).size << endl; //THIS DOES NOT COMPILE return 0; }

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  • How difficult is it for an old-school programmer to pick up an FPGA kit and make something useful wi

    - by JUST MY correct OPINION
    I'm an old, old, old coder. (How old? I've used paper tape in anger.) I've programmed in a lot of languages and under a lot of paradigms (spaghetti, structured, object-oriented, functional and a smattering of logical). I'm getting bored. FPGAs look interesting to me. I have the crazy notion of resurrecting some of the ancient hardware I worked on in the days using FPGAs. I know this can be done because I've seen PDP-10 and PDP-11 implementations in FPGAs. I'd like to do the same for a few machines that are perhaps not as popular as those two, however. While I am an old, old coder, what I am not is an electronics or computer systems engineer. I'll be learning from scratch if I go down this path. My question, therefore, is two-fold: How difficult will it be for this old dinosaur to pick up and learn FPGAs to the point that interesting (not necessarily practical -- more from a hobbyist perspective) projects can be made? What should I start with learning-wise to go down this path? I know where to get FPGA kits, but I haven't found anything like "FPGAs for Complete Dinosaurs" yet anywhere out there.

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  • Conditional insert as a single database transaction in HSQLDB 1.8?

    - by Kevin Pauli
    I'm using a particular database table like a "Set" data structure, i.e., you can attempt to insert the same row several times, but it will only contain one instance. The primary key is a natural key. For example, I want the following series of operations to work fine, and result in only one row for Oklahoma: insert into states_visited (state_name) values ('Oklahoma'); insert into states_visited (state_name) values ('Texas'); insert into states_visited (state_name) values ('Oklahoma'); I am of course getting an error due to the duplicate primary key on subsequent inserts of the same value. Is there a way to make the insert conditional, so that these errors are not thrown? I.e. only do the the insert if the natural key does not already exist? I know I could do a where clause and a subquery to test for the row's existence first, but it seems that would be expensive. That's 2 physical operations for one logical "conditional insert" operation. Anything like this in SQL? FYI I am using HSQLDB 1.8

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  • c# STILL returning wrong number of cores

    - by Justin
    Ok, so I posted in In C# GetEnvironmentVariable("NUMBER_OF_PROCESSORS") returns the wrong number asking about how to get the correct number of cores in C#. Some helpful people directed me to a couple of questions where similar questions were asked but I have already tried those solutions. My question was then closed as being the same as another question, which is true, it is, but the solution given there didn't work. So I'm opening another one hoping that someone may be able to help realising that the other solutions DID NOT work. That question was How to find the Number of CPU Cores via .NET/C#? which used WMI to try to get the correct number of cores. Well, here's the output from the code given there: Number Of Cores: 32 Number Of Logical Processors: 32 Number Of Physical Processors: 4 As per my last question, the machine is a 64 core AMD Opteron 6276 (4x16 cores) running Windows Server 2008 R2 HPC edition. Regardless of what I do Windows always seems to return 32 cores even though 64 are available. I have confirmed the machine is only using 32 and if I hardcode 64 cores, then the machine uses all of them. I'm wondering if there might be an issue with the way the AMD CPUs are detected. FYI, in case you haven't read the last question, if I type echo %NUMBER_OF_PROCESSORS" at the command line, it returns 64. It just won't do it in a programming environment. Thanks, Justin UPDATE: Outputting PROCESSOR_ARCHITECTURE returns AMD64 from the command line, but x86 from the program. The program is 32-bit running on 64-bit hardware. I was asked to compile it to 64-bit but it still shows 32 cores.

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