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• Different programming languages possibilities

  - by b-gen-jack-o-neill

  Hello. This should be very simple question. There are many programming languages out there, compiled into machine code or managed code. I first started with ASM back in high school. Assembler is very nice, since you know what exactly CPU does. Next, (as you can see from my other questions here) I decided to learn C and C++. I choosed C becouse from what I read it is the language with output most close to assembler-written programs. But, what I want to know is, can any other Windows programming language out there call win32 API? To be exact, like C has its special header and functions for win32 api interactions, is this assumed to be some important part of programming language? Or are there any languages that have no support for calling win32 API, or just use console to IO and some functions for basic file IO? Becouse, for Windows programming with graphic output, it is essential to have acess to win32 API. I know this question might seem silly, but still please, help me, I ask for study porposes. Thanks.

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• Hundreds of custom UserControls create thousands of USER Objects

  - by Andy Blackman

  I'm creating a dashboard application that shows hundreds of "items" on a FlowLayoutPanel. Each "item" is a UserControl that is made up of 12 or labels. My app queries a database and then creates an "item" instance for each record, populating ethe labels and textboxes with data before adding it to the FlowLayoutPanel. After adding about 560 items to the panel, I noticed that the USER Objects count in my Task Manager had gone up to about 7300, which was much much larger than any other app on my machine. I did a quick spot of mental arithmetic (OK, I might have used calc.exe) and figured that 560 * 13 (12 labels plus the UserControl itself) is 7280. So that suddenly gave away where all the objects were coming from... Knowing that there is a 10,000 USER object limit before windows throws in the towel, I'm trying to figure better ways of drawing these items onto the FlowLayoutPanel. My ideas so far are as follows: 1) User-draw the "item", using graphics.DrawText and DrawImage in place of many of the labels. I'm hoping that this will mean 1 item = 1 USER Object, not 13. 2) Have 1 instance of the "item", then for each record, populate the instance and use the Control.DrawToBitmap() method to grab an image and then use that in the FlowLayoutPanel (or similar) So... Does anyone have any other suggestions ??? P.S. It's a zoomable interface, so I have already ruled out "Paging" as there is a requirement to see all items at once :( Thanks everyone.

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• Designing a chain of states

  - by devoured elysium

  I want to model a kind of FSM(Finite State Machine). I have a sequence of states (let's say, from StateA to StateZ). This sequence is called a Chain and is implemented internally as a List. I will add states by the order I want them to run. My purpose is to be able to make a sequence of actions in my computer (for example, mouse clicks). (I know this has been done a zillion times). So a state is defined as a: boolean Precondition() <- Checks to see if for this state, some condition is true. For example, if I want to click in the Record button of a program, in this method I would check if the program's process is running or not. If it is, go to the next state in the chain list, otherwise, go to what was defined as the fail state (generally is the first state of them all). IState GetNextState() <- Returns the next state to evaluate. If Precondition() was sucessful, it should yield the next state in the chain otherwise it should yield the fail state. Run() Simply checks the Precondition() and sets the internal data so GetNextState() works as expected. So, a naive approach to this would be something like this: Chain chain = new Chain(); //chain.AddState(new State(Precondition, FailState, NextState) <- Method structure chain.AddState(new State(new WinampIsOpenCondition(), null, new <problem here, I want to referr to a state that still wasn't defined!>); The big problem is that I want to make a reference to a State that at this point still wasn't defined. I could circumvent the problem by using strings when refrering to states and using an internal hashtable, but isn't there a clearer alternative? I could just pass only the pre-condition and failure states in the constructor, having the chain just before execution put in each state the correct next state in a public property but that seems kind of awkward.

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• Memory allocation for a matrix in C

  - by Snogzvwtr

  Why is the following code resulting in Segmentation fault? (I'm trying to create two matrices of the same size, one with static and the other with dynamic allocation) #include <stdio.h> #include <stdlib.h> //Segmentation fault! int main(){ #define X 5000 #define Y 6000 int i; int a[X][Y]; int** b = (int**) malloc(sizeof(int*) * X); for(i=0; i<X; i++){ b[i] = malloc (sizeof(int) * Y); } } Weirdly enough, if I comment out one of the matrix definitions, the code runs fine. Like this: #include <stdio.h> #include <stdlib.h> //No Segmentation fault! int main(){ #define X 5000 #define Y 6000 int i; //int a[X][Y]; int** b = (int**) malloc(sizeof(int*) * X); for(i=0; i<X; i++){ b[i] = malloc (sizeof(int) * Y); } } or #include <stdio.h> #include <stdlib.h> //No Segmentation fault! int main(){ #define X 5000 #define Y 6000 int i; int a[X][Y]; //int** b = (int**) malloc(sizeof(int*) * X); //for(i=0; i<X; i++){ // b[i] = malloc (sizeof(int) * Y); //} } I'm running gcc on Linux on a 32-bit machine.

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• VS ASP.NET 500 Server Error

  - by rlb.usa

  Hey guys, I'm having a super weird problem with my VS 2008 solution. We had this hand-coded ASP.NET compiled web app on our old IIS6/Win2003 server, working great, moved it to our new IIS7/Win2008 server, still working great, but when I try to compile the application and publish it again to our new Win2008 server, I get server 500 errors. It's ASP.NET 2.0 with AJAX extensions and AJAX control toolkit. I'm not too great with server issues, or even sure if it is a server issue but here are some more symptoms... ? I know the website works (it only differs by some minor code fixes) and can use it's code on a development machine, there are no errors, and it publishes fine. Publishing (using the DLL files), and even not publishing and trying to use the code-behind files on our new server, both no success. The old website does work on the new server just fine. If I put a simple hello world html page in the website's virtual directory, with the old code, it works fine, but with the new code, that html page gets the 500 error. And in fact, oddly, I can add all the files to the website, only when I add the web.config, do I get the 500 error. The web.config has not changed. Tried stopping and restarting IIS What's the problem, here? Any ideas, what else can I do to troubleshoot the problem?

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• CXF code first service, WSDL generation; soap:address changes?

  - by jcalvert

  I have a simple Java interface/implementation I am exposing via CXF. I have a jaxws element in my Spring configuration file like this: <jaxws:endpoint id="managementServiceJaxws" implementor="#managementService" address="/jaxws/ManagementService" > </jaxws:endpoint> It generates the WSDL from my annotated interface and exposes the service. Then when I hit http://myhostname/cxf/jaxws/ManagementService?wsdl I get a lovely WSDL. At the bottom in the wsdl:service element, I'll see <soap:address location="http://myhostname/cxf/jaxws/ManagementService"/> However, some time a day or so later, with no application restart, hitting that same url produces: This causes a number of problems, but what I really want is to fix it. Right now, there's a particular client to the webservice that sets the endpoint to localhost; because it runs on the same machine. Is it possible the wsdl is getting regenerated and cached and then exposing the 'localhost' version? In part I don't know the exact mechanism by which one goes from a ?wsdl request in CXF to the response. It seems almost certain that it's retrieving some cached version, given that it's supposed to be determining the address by asking the servletcontainer (Jetty). For reference I know a stopgap solution is using the hostname on the client and making sure an alias in place so that it goes over the loopback. EDIT: For reference, I confirmed that if I bring my application up and first hit it over localhost, then querying for the wsdl via the hostname shows the address as localhost. Conversely, first hitting it over the hostname causes localhost requests to show the hostname. So obviously something is getting cached here.

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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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• Subversion freaking out on me!

  - by Malfist

  I have two copies of a site, one is the production copy, and the other is the development copy. I recently added everything in the production to a subversion repository hosted on our linux backup server. I created a tag of the current version and I was done. I then copied the development copy overtop of the production copy (on my local machine where I have everything checked out). There are only 10-20 files changed, however, when I use tortoise SVN to do a commit, it says every file has changed. The diff file generated shows subversion removing everything, and replacing it with the new version (which is the exact same). What is going on? How do I fix it? An example diff: Index: C:/Users/jhollon/Documents/Visual Studio 2008/Projects/saloon/trunk/components/index.html =================================================================== --- C:/Users/jhollon/Documents/Visual Studio 2008/Projects/saloon/trunk/components/index.html (revision 5) +++ C:/Users/jhollon/Documents/Visual Studio 2008/Projects/saloon/trunk/components/index.html (working copy) @@ -1,4 +1,4 @@ -<html> -<body bgcolor="#FFFFFF"> -</body> +<html> +<body bgcolor="#FFFFFF"> +</body> </html> \ No newline at end of file

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• Sharepoint fails to load a C++ dll on windows 2008

  - by Nathan

  I have a sharepoint DLL that does some licensing things and as part of the code it uses an external C++ DLL to get the serial number of the hardisk. When i run this application on windows server 2003 it works fine, but on 2008 the whole site (loaded on load) crashes and resets continually. This is not 2008 R2 and is the same in 64 or 32 bits. If i put a debugger.break before the dll execution then I see the code get to the point of the break then never come back into the dll again. I do get some debug assertion warnings from within the function, again only in 2008, but im not sure this is related. I created a console app that runs the c# dll, which in turn loads the c++ dll, and this works perfectly on 2008 (although does show the assertion errors, but I have suppressed these now). The assertion errors are not in my code but within ICtypes.c and not something I can debug. If i put a breakpoint in the DLL it is never hit and the compiler says : "step in: Stepping over non user code" if i try to debug into the DLL using VS. I have tried wrapping the code used to call the DLL in: SPSecurity.RunWithElevatedPrivileges(delegate() but this also does not help. I have the sourcecode for this DLL so that is not a problem. If i delete the DLL from the directory I get an error about a missing DLL, if i replace it back to no error or warning just a complete failure. If i replace this code with a hardcoded string the whole application works fine. Any advice would be much appreciated, I can't understand why it works as a console app yet not when run by sharepoint, this is with the same user account, on the same machine... This is the code used to call the DLL: [DllImport("idDll.dll", EntryPoint = "GetMachineId", SetLastError = true)] extern static string GetComponentId([MarshalAs(UnmanagedType.LPStr)]String s); public static string GetComponentId() { Debugger.Break(); if (_machine == string.Empty) { string temp = ""; id= ComponentId.GetComponentId(temp); } return id; }

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• Unexpected output using subprocess in Python

  - by Vic

  I am trying to run a shell command from within my Python (version 2.6.5) code, but it is generating different output than the same command run within the shell (bash): bash: ~> ifconfig eth0 | sed -rn 's/inet addr:(([0-9]{1,3}\.){3}[0-9]{1,3}).*/\1/p' | sed 's/^[ \t]*//;s/[ \t]*$//' 192.168.1.10 Python: >>> def get_ip(): ... cmd_string = "ifconfig eth0 | sed -rn \'s/inet addr:(([0-9]{1,3}\.){3}[0-9]{1,3}).*/\1/p' | sed 's/^[ \t]*//;s/[ \t]*$//\'" ... process = subprocess.Popen(cmd_string, shell=True, stdout=subprocess.PIPE) ... out, err = process.communicate() ... return out ... >>> get_ip() '\x01\n' My guess is that I need to escape the quotes somehow when running in python, but I am not sure how to go about this. NOTE: I cannot install additional modules or update python on the machine that this code needs to be run on. It needs to work as-is with Python 2.6.5 and the standard library.

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• Why is PLINQ slower than LINQ for this code?

  - by Rob Packwood

  First off, I am running this on a dual core 2.66Ghz processor machine. I am not sure if I have the .AsParallel() call in the correct spot. I tried it directly on the range variable too and that was still slower. I don't understand why... Here are my results: Process non-parallel 1000 took 146 milliseconds Process parallel 1000 took 156 milliseconds Process non-parallel 5000 took 5187 milliseconds Process parallel 5000 took 5300 milliseconds using System; using System.Collections.Generic; using System.Diagnostics; using System.Linq; namespace DemoConsoleApp { internal class Program { private static void Main() { ReportOnTimedProcess( () => GetIntegerCombinations(), "non-parallel 1000"); ReportOnTimedProcess( () => GetIntegerCombinations(runAsParallel: true), "parallel 1000"); ReportOnTimedProcess( () => GetIntegerCombinations(5000), "non-parallel 5000"); ReportOnTimedProcess( () => GetIntegerCombinations(5000, true), "parallel 5000"); Console.Read(); } private static List<Tuple<int, int>> GetIntegerCombinations( int iterationCount = 1000, bool runAsParallel = false) { IEnumerable<int> range = Enumerable.Range(1, iterationCount); IEnumerable<Tuple<int, int>> integerCombinations = from x in range from y in range select new Tuple<int, int>(x, y); return runAsParallel ? integerCombinations.AsParallel().ToList() : integerCombinations.ToList(); } private static void ReportOnTimedProcess( Action process, string processName) { var stopwatch = new Stopwatch(); stopwatch.Start(); process(); stopwatch.Stop(); Console.WriteLine("Process {0} took {1} milliseconds", processName, stopwatch.ElapsedMilliseconds); } } }

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• Where are the network boundaries in the Java Connector Architecture (JCA)?

  - by Laird Nelson

  I am writing a JCA resource adapter. I'm also, as I go, trying to fully understand the connection management portion of the JCA specification. As a thought experiment, pretend that the only client of this adapter will be a Swing Java Application Client located on a different machine. Also assume that the resource adapter will communicate with its "enterprise information system" (EIS) over the network as well. As I understand the JCA specification, the .rar file is deployed to the application server. The application server creates the .rar file's implementation of the ManagedConnectionFactory interface. It then asks it to produce a connection factory, which is the opaque object that is deployed to JNDI for the user to use to obtain a connection to the resource. (In the case of JDBC, the connection factory is a javax.sql.DataSource.) It is a requirement that the connection factory retain a reference to the application-server-supplied ConnectionManager, which, in turn, is required to be Serializable. This makes sense--in order for the connection factory to be stored in JNDI, it must be serializable, and in order for it to keep a reference to the ConnectionManager, the ConnectionManager must also be serializable. So fine, this little object graph gets installed in the application client's JNDI tree. This is where I start to get queasy. Is the ConnectionManager--the piece supplied by the application server that is supposed to handle connection management, sharing, pooling, etc.--wholly present on the client at this point? One of its jobs is to create ManagedConnection instances, and a ManagedConnection is not required to be Serializable, and the user connection handles it vends are also not required to be Serializable. That suggests to me that the whole connection pooling machinery is shipped wholesale to the application client and stuffed into its JNDI tree. Does this all mean that JCA interactions from the client side bypass the server-side componentry of the application server? Where are the network boundaries in the JCA API?

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• Java Swing rendering bug on Windows 7 look-and-feel?

  - by John B.

  The knob on vertical JSlider's on my Windows 7 machine (with native look-and-feel) is really, really tiny in both directions. Not just skinny but short as well. Can anyone confirm this? Should I report it? If so, where? Thanks! Here is the code for the sample program (in the screen shot): import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JSlider; import javax.swing.SwingConstants; import javax.swing.UIManager; public class SliderTest { public static void main( String[] args ) { // Set the look and feel to that of the system try { UIManager.setLookAndFeel( UIManager.getSystemLookAndFeelClassName() ); } catch ( Exception e ) { System.err.println( e ); } // Launch the GUI from the event dispatch thread javax.swing.SwingUtilities.invokeLater( new Runnable() { public void run () { JFrame window = new JFrame(); window.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE ); JPanel contentPane = new JPanel(); contentPane.add( new JSlider(SwingConstants.HORIZONTAL) ); contentPane.add( new JSlider(SwingConstants.VERTICAL) ); window.setContentPane( contentPane ); window.pack(); window.setLocationRelativeTo( null ); // Center window window.setVisible( true ); } }); } }

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• RMagick transparent_color deprecated? What's the alternative?

  - by user315975

  I'm developing an app that does a fair amount of generating transparent pngs on the fly. These are used as overlays, to show areas of interest in a graphic, so they have to have transparent backgrounds. I am developing in Ruby on Rails, deploying on Heroku. What works fine in development is not working in production. I get this error when I call a drawing routine using RMagick: NotImplementedError (the `transparent_color=' method is not supported by ImageMagick 6.2.4): /usr/local/lib/ruby/gems/1.8/gems/rmagick-1.15.17/lib/RMagick.rb:1691:in `transparent_color=' I'm using RMagick version 2.12.1 on the development machine, but I'm not exactly certain how to discover the version of ImageMagick that it's running, so I'm not sure if this is a case of my local code being behind or ahead. I'm hoping behind, because perhaps then there'll be a replacement for this call. Does anyone know what the fix is here? What's required to generate a transparent background, if not the call I'm using? I can't find this in the documentation: in fact, it was on a third-party site that I found mention of this capability.

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• How do I distribute my slightly customized Linux in VirtualBox?

  - by goodrone

  Suppose I've got some Arch Linux installation which I'd like to distribute among students with (sometimes very) basic Linux knowledge to make them able to compile C programs in an environment very similar to that in the university. (Things like Cygwin or MinGW seem to be inappropriate here.) I also choose VirtualBox as a holder for the virtual system. The question is: how do I distribute it? I mean: installing VirtualBox on the target machine (if not still installed) uncompressing and copying my image file (.VDI) registering the image (so that VirtualBox could see it when launched) configuring the guest system in VirtualBox (network, memory, etc.) optionally installing PuTTY to simplify interfacing with the guest Linux Should I create an installer? Which one? Or just write some .BAT-scripts? (Target host system is Windows, mostly XP and Vista.) I definately don't want to have a webpage with screen shot explaining where to click and what to press, because it's boring. Additionaly, what will be the best (the most user-friendly) way to configure network when the guest Linux system is run for the first time?

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• Perl 500 internal server error. Something wrong with my code.

  - by Nitish

  I get a 500 internal server error when I try to run the code below in a web server which supports perl: #! /usr/bin/perl use LWP; my $ua = LWP::UserAgent->new; $ua->agent("TestApp/0.1 "); $ua->env_proxy(); my $req = HTTP::Request->new(POST => 'http://www.google.com/loc/json'); $req->content_type('application/jsonrequest'); $req->content('{ "cell_towers": [{"location_area_code": "55000", "mobile_network_code": "95", "cell_id": "20491", "mobile_country_code": "404"}], "version": "1.1.0", "request_address": "true"}'); my $res = $ua->request($req); if ($res->is_success) { print $res->content,"\n"; } else { print $res->status_line, "\n"; return undef; } But there is no error when I run the code below: #! /usr/bin/perl use CGI::Carp qw(fatalsToBrowser); print "Content-type: text/html\n\n"; print "<HTML>\n"; print "<HEAD><TITLE>Hello World!</TITLE></HEAD>\n"; print "<BODY>\n"; print "<H2>Hello World!</H2> <br /> \n"; foreach $key (sort keys(%ENV)) { print "$key = $ENV{$key}<p>" ; } print "</BODY>\n"; print "</HTML>\n"; So I think there is some problem with my code. When I run the first perl script in my local machine with the -wc command, it says that the syntax is OK. Help me please.

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• My PHP code is commented out

  - by Mr A

  Before everything happened, I was running this wordpress install for developing themes using xampp. But I decided to upgrade the memory of this machine from 2GB to 6GB since I need extra room for applications. I back-up my code in a separate partition by copying them. Since I have a 32bit OS at the time, I format the computer and installed a 64bit version. All is well and fine the OS side. When I setup my web dev environment something goes wrong. When I imported my htdocs back, first by just fully copying them to a new fresh install of xampp and notice that all of the codes that put are not working. My CI code is displaying my PHP code in the browser. My theme in wordpress is also commenting out my PHP code when I view the source. The themes included in my fresh wordpress install works so there's something I am missing here. From the looks of it, the php is being executed properly since anything that I install works. Just that the ones that came from a previous xampp is not.

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• Set service dependencies after install

  - by Dennis

  I have an application that runs as a Windows service. It stores various things settings in a database that are looked up when the service starts. I built the service to support various types of databases (SQL Server, Oracle, MySQL, etc). Often times end users choose to configure the software to use SQL Server (they can simply modify a config file with the connection string and restart the service). The problem is that when their machine boots up, often times SQL Server is started after my service so my service errors out on start up because it can't connect to the database. I know that I can specify dependencies for my service to help guide the Windows service manager to start the appropriate services before mine. However, I don't know what services to depend upon at install time (when my service is registered) since the user can change databases later on. So my question is: is there a way for the user to manually indicate the service dependencies based on the database that they are using? If not, what is the proper design approach that I should be taking? I've thought about trying to do something like wait 30 seconds after my service starts up before connecting to the database but this seems really flaky for various reasons. I've also considered trying to "lazily" connect to the database; the problem is that I need a connection immediately upon start up since the database contains various pieces of vital info that my service needs when it first starts. Any ideas?

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• Using "from __future__ import division" in my program, but it isn't loaded with my program

  - by Sara Fauzia

  I wrote the following program in Python 2 to do Newton's method computations for my math problem set, and while it works perfectly, for reasons unbeknownst to me, when I initially load it in ipython with %run -i NewtonsMethodMultivariate.py, the Python 3 division is not imported. I know this because after I load my Python program, entering x**(3/4) gives "1". After manually importing the new division, then x**(3/4) remains x**(3/4), as expected. Why is this? # coding: utf-8 from __future__ import division from sympy import symbols, Matrix, zeros x, y = symbols('x y') X = Matrix([[x],[y]]) tol = 1e-3 def roots(h,a): def F(s): return h.subs({x: s[0,0], y: s[1,0]}) def D(s): return h.jacobian(X).subs({x: s[0,0], y: s[1,0]}) if F(a) == zeros(2)[:,0]: return a else: while (F(a)).norm() > tol: a = a - ((D(a))**(-1))*F(a) print a.evalf(10) I would use Python 3 to avoid this issue, but my Linux distribution only ships SymPy for Python 2. Thanks to the help anyone can provide. Also, in case anyone was wondering, I haven't yet generalized this script for nxn Jacobians, and only had to deal with 2x2 in my problem set. Additionally, I'm slicing the 2x2 zero matrix instead of using the command zeros(2,1) because SymPy 0.7.1, installed on my machine, complains that "zeros() takes exactly one argument", though the wiki suggests otherwise. Maybe this command is only for the git version.

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• Run code before class instanciation in ActionScript 3

  - by soow.fr

  I need to run code in a class declaration before its instanciation. This would be especially useful to automatically register classes in a factory. See: // Main.as public class Main extends Sprite { public function Main() : void { var o : Object = Factory.make(42); } } // Factory.as public class Factory { private static var _factory : Array = new Array(); public static function registerClass(id : uint, c : Class) : void { _factory[id] = function () : Object { return new c(); }; } public static function make(id : uint) : Object { return _factory[id](); } } // Foo.as public class Foo { // Run this code before instanciating Foo! Factory.registerClass(42, Foo); } AFAIK, the JIT machine for the ActionScript language won't let me do that since no reference to Foo is made in the Main method. The Foo class being generated, I can't (and don't want to) register the classes in Main: I'd like to register all the exported classes in a specific package (or library). Ideally, this would be done through package introspection, which doesn't exist in ActionScript 3. Do you know any fix (or other solution) to my design issue?

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• Can knowing C actually hurt the code you write in higher level languages?

  - by Jurily

  The question seems settled, beaten to death even. Smart people have said smart things on the subject. To be a really good programmer, you need to know C. Or do you? I was enlightened twice this week. The first one made me realize that my assumptions don't go further than my knowledge behind them, and given the complexity of software running on my machine, that's almost non-existent. But what really drove it home was this Slashdot comment: The end result is that I notice the many naive ways in which traditional C "bare metal" programmers assume that higher level languages are implemented. They make bad "optimization" decisions in projects they influence, because they have no idea how a compiler works or how different a good runtime system may be from the naive macro-assembler model they understand. Then it hit me: C is just one more abstraction, like all others. Even the CPU itself is only an abstraction! I've just never seen it break, because I don't have the tools to measure it. I'm confused. Has my mind been mutilated beyond recovery, like Dijkstra said about BASIC? Am I living in a constant state of premature optimization? Is there hope for me, now that I realized I know nothing about anything? Is there anything to know, even? And why is it so fascinating, that everything I've written in the last five years might have been fundamentally wrong? To sum it up: is there any value in knowing more than the API docs tell me? EDIT: Made CW. Of course this also means now you must post examples of the interpreter/runtime optimizing better than we do :)

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• What library can I use to do simple, lightweight message passing?

  - by Mike

  I will be starting a project which requires communication between distributed nodes(the project is in C++). I need a lightweight message passing library to pass very simple messages(basically just strings of text) between nodes. The library must have the following characteristics: No external setup required. I need to be able to get everything up-and-running in my code - I don't want to require the user to install any packages or edit any configuration files(other than a list of IP addresses and ports to connect to). The underlying protocol which the library uses must be TCP(or if it is UDP, the library must guarantee the eventual receipt of the message). The library must be able to send and receive arbitrarily large strings(think up to 3GB+). The library needn't support any security mechanisms, fault tolerance, or encryption - I just need it to be fast, simple, and easy to use. I've considered MPI, but concluded it would require too much setup on the user's machine for my project. What library would you recommend for such a project? I would roll my own, but due to time constraints, I don't think that will be feasible.

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• Stored procedure for generic MERGE

  - by GilliVilla

  I have a set of 10 tables in a database (DB1). And there are 10 tables in another database (DB2) with exact same schema on the same SQL Server 2008 R2 database server machine. The 10 tables in DB1 are frequently updated with data. I intend to write a stored procedure that would run once every day for synchronizing the 10 tables in DB1 with DB2. The stored procedure would make use of the MERGE statement. Now, my aim is to make this as generic and parametrized as possible. That is, accommodate for more tables down the line... and accommodate different source and target DB names. Definitely no hard coding is intended. This is my algorithm so far: Have the database names as parameters Have the first query within the stored procedure... result in giving the names of the 10 tables from a lookup table (this can be 10, 20 or whatever) Have a generic MERGE statement that does the sync for each of the above set of tables (based on primary key?) This is where I need more inputs on. What is the best way to achieve this stored procedure? SQL syntax would be helpful.

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• File upload fails when user is authenticated. Using IIS7 Integrated mode.

  - by Nikkelmann

  These are the user identities my website tells me that it uses: Logged on: NT AUTHORITY\NETWORK SERVICE (Can not write any files at all) and Not logged on: WSW32\IUSR_77 (Can write files to any folder) I have a ASP.NET 4.0 website on a shared hosting IIS7 web server running in Integrated mode with 32-bit applications support enabled and MSSQL 2008. Using classic mode is not an option since I need to secure some static files and I use Routing. In my web.config file I have set the following: <system.webServer> <modules runAllManagedModulesForAllRequests="true" /> </system.webServer> My hosting company says that Impersonation is enabled by default on machine level, so this is not something I can change. I asked their support and they referred me to this article: http://www.codinghub.net/2010/08/differences-between-integrated-mode-and.html Citing this part: Different windows identity in Forms authentication When Forms Authentication is used by an application and anonymous access is allowed, the Integrated mode identity differs from the Classic mode identity in the following ways: * ServerVariables["LOGON_USER"] is filled. * Request.LogognUserIdentity uses the credentials of the [NT AUTHORITY\NETWORK SERVICE] account instead of the [NT AUTHORITY\INTERNET USER] account. This behavior occurs because authentication is performed in a single stage in Integrated mode. Conversely, in Classic mode, authentication occurs first with IIS 7.0 using anonymous access, and then with ASP.NET using Forms authentication. Thus, the result of the authentication is always a single user-- the Forms authentication user. AUTH_USER/LOGON_USER returns this same user because the Forms authentication user credentials are synchronized between IIS 7.0 and ASP.NET. A side effect is that LOGON_USER, HttpRequest.LogonUserIdentity, and impersonation no longer can access the Anonymous user credentials that IIS 7.0 would have authenticated by using Classic mode. How do I set up my website so that it can use the proper identity with the proper permissions? I've looked high and low for any answers regarding this specific problem, but found nil so far... I hope you can help!

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• what can cause large discrepancy between minor GC time and total pause time?

  - by cxcg

  We have a latency-sensitive application, and are experiencing some GC-related pauses we don't fully understand. We occasionally have a minor GC that results in application pause times that are much longer than the reported GC time itself. Here is an example log snippet: 485377.257: [GC 485378.857: [ParNew: 105845K-621K(118016K), 0.0028070 secs] 136492K-31374K(1035520K), 0.0028720 secs] [Times: user=0.01 sys=0.00, real=1.61 secs] Total time for which application threads were stopped: 1.6032830 seconds The total pause time here is orders of magnitude longer than the reported GC time. These are isolated and occasional events: the immediately preceding and succeeding minor GC events do not show this large discrepancy. The process is running on a dedicated machine, with lots of free memory, 8 cores, running Red Hat Enterprise Linux ES Release 4 Update 8 with kernel 2.6.9-89.0.1EL-smp. We have observed this with (32 bit) JVM versions 1.6.0_13 and 1.6.0_18. We are running with these flags: -server -ea -Xms512m -Xmx512m -XX:+UseConcMarkSweepGC -XX:NewSize=128m -XX:MaxNewSize=128m -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintGCApplicationStoppedTime -XX:-TraceClassUnloading Can anybody offer some explanation as to what might be going on here, and/or some avenues for further investigation?

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