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  • What would be the safest way to store objects of classes derived from a common interface in a common

    - by Svenstaro
    I'd like to manage a bunch of objects of classes derived from a shared interface class in a common container. To illustrate the problem, let's say I'm building a game which will contain different actors. Let's call the interface IActor and derive Enemy and Civilian from it. Now, the idea is to have my game main loop be able to do this: // somewhere during init std::vector<IActor> ActorList; Enemy EvilGuy; Civilian CoolGuy; ActorList.push_back(EvilGuy); ActorList.push_back(CoolGuy); and // main loop while(!done) { BOOST_FOREACH(IActor CurrentActor, ActorList) { CurrentActor.Update(); CurrentActor.Draw(); } } ... or something along those lines. This example obviously won't work but that is pretty much the reason I'm asking here. I'd like to know: What would be the best, safest, highest-level way to manage those objects in a common heterogeneous container? I know about a variety of approaches (Boost::Any, void*, handler class with boost::shared_ptr, Boost.Pointer Container, dynamic_cast) but I can't decide which would be the way to go here. Also I'd like to emphasize that I want to stay away as far as possible from manual memory management or nested pointers. Help much appreciated :).

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  • Loading machinecode from file into memory and executing in C -- mprotect failing

    - by chartreusekitsune
    Hi I'm trying to load raw machine code into memory and run it from within a C program, right now when the program executes it breaks when trying to run mprotect on the memory to make it executable. I'm also not entirely sure that if the memory does get set right it will execute. What I currently have is the following: #include <memory.h> #include <sys/mman.h> #include <stdio.h> int main ( int argc, char **argv ) { FILE *fp; int sz = 0; char *membuf; int output = 0; fp = fopen(argv[1],"rb"); if(fp == NULL) { printf("Failed to open file, aborting!\n"); exit(1); } fseek(fp, 0L, SEEK_END); sz = ftell(fp); fseek(fp, 0L, SEEK_SET); membuf = (char *)malloc(sz*sizeof(char)); if(membuf == NULL) { printf("Failed to allocate memory, aborting!\n"); exit(1); } memset(membuf, 0x90, sz*sizeof(char)); if( mprotect(membuf, sz*sizeof(char), PROT_EXEC | PROT_READ | PROT_WRITE) == -1) { printf("mprotect failed!!! aborting!\n"); exit(1); } if((sz*sizeof(char)) != fread(membuf, sz*sizeof(char), 1, fp)) { printf("Read failed, aborting!\n"); exit(1); } __asm__ ( "call %%eax;" : "=a" (output) : "a" (membuf) ); printf("Output = %x\n", output); return 0; }

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  • What does "active directory integration" mean in your .NET app?

    - by flipdoubt
    Our marketing department comes back with "active directory integration" being a key customer request, but our company does not seem to have the attention span to (1) decide on what functional changes we want to make toward this end, (2) interview a broad range of customer to identify the most requested functional changes, and (3) still have this be the "hot potato" issue next week. To help me get beyond the broad topic of "active directory integration," what does it mean in your .NET app, both ASP.NET and WinForms? Here are some sample changes I have to consider: When creating and managing users in your app, are administrators presented with a list of all AD users or just a group of AD users? When creating new security groups within your app (we call them Departments, like "Human Resources"), should this create new AD groups? Do administrators assign users to security groups within your app or outside via AD? Does it matter? Is the user signed on to your app by virtue of being signed on to Windows? If not, do you track users with your own user table and some kind of foreign key into AD? What foreign key do you use to link app users to AD users? Do you have to prove your login process protects user passwords? What foreign key do you use to link app security groups to AD security groups? If you have a WinForms component to your app (we have both ASP.NET and WinForms), do you use the Membership Provider in your WinForms app? Currently, our Membership and Role management predates the framework's version, so we do not use the Membership Provider. Am I missing any other areas of functional changes? Followup question Do apps that support "active directory integration" have the ability to authenticate users against more than one domain? Not that one user would authenticate to more than one domain but that different users of the same system would authenticate against different domains.

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  • can't commit or rollback, MySQL out of sync error on .net

    - by sergiogx
    Im having trouble with a stored procedure, I can't commit after I execute it. Its showing this error "[System.Data.Odbc.OdbcException] = {"ERROR [HY000] [MySQL][ODBC 5.1 Driver]Commands out of sync; you can't run this command now"}" The SP by itself works fine. does anyone have idea of what might be happening? .net code: [WebMethod()] [SoapHeader("sesion")] public Boolean aceptarTasaCero(int idMunicipio, double valor) { Boolean resultado = false; OdbcConnection cxn = new OdbcConnection(); cxn.ConnectionString = ConfigurationManager.ConnectionStrings["mysqlConnection"].ConnectionString; cxn.Open(); OdbcCommand cmd = new OdbcCommand("call aceptarTasaCero(?,?)", cxn); cmd.Parameters.Add("idMunicipio", OdbcType.Int).Value = idMunicipio; cmd.Parameters.Add("valor", OdbcType.Double).Value = valor; cmd.Transaction = cxn.BeginTransaction(); try { OdbcDataReader dr = cmd.ExecuteReader(); if (dr.Read()) { resultado = Convert.ToBoolean(dr[0]); } cmd.Transaction.Commit(); } catch (Exception ex) { ExBi.log(ex, sesion.idUsuario); cmd.Transaction.Rollback(); } finally { cxn.Close(); } return resultado; } and this is the code for the stored procedure DELIMITER $$ DROP PROCEDURE IF EXISTS `aceptartasacero` $$ CREATE DEFINER=`database`@`%` PROCEDURE `aceptartasacero`(pidMun INTEGER, pvalor double) BEGIN declare vExito BOOLEAN; INSERT INTO tasacero(anio,valor,idmunicipios) VALUES(YEAR(curdate()),pValor,pidMun); set vExito = true; select vExito; END $$ DELIMITER ; thanks.

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  • Comparing two collections for equality

    - by Crossbrowser
    I would like to compare two collections (in C#), but I'm not sure of the best way to implement this efficiently. I've read the other thread about Enumerable.SequenceEqual, but it's not exactly what I'm looking for. In my case, two collections would be equal if they both contain the same items (no matter the order). Example: collection1 = {1, 2, 3, 4}; collection2 = {2, 4, 1, 3}; collection1 == collection2; // true What I usually do is to loop through each item of one collection and see if it exists in the other collection, then loop through each item of the other collection and see if it exists in the first collection. (I start by comparing the lengths). if (collection1.Count != collection2.Count) return false; // the collections are not equal foreach (Item item in collection1) { if (!collection2.Contains(item)) return false; // the collections are not equal } foreach (Item item in collection2) { if (!collection1.Contains(item)) return false; // the collections are not equal } return true; // the collections are equal However, this is not entirely correct, and it's probably not the most efficient way to do compare two collections for equality. An example I can think of that would be wrong is: collection1 = {1, 2, 3, 3, 4} collection2 = {1, 2, 2, 3, 4} Which would be equal with my implementation. Should I just count the number of times each item is found and make sure the counts are equal in both collections? The examples are in some sort of C# (let's call it pseudo-C#), but give your answer in whatever language you wish, it does not matter. Note: I used integers in the examples for simplicity, but I want to be able to use reference-type objects too (they do not behave correctly as keys because only the reference of the object is compared, not the content).

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  • Is it possible to search locally in jqGrid with treeGrid installed

    - by Nehu
    I am using jqGrid with treeGrid. I have added a filterToolbar. I would like to search locally instead of having a server call. The treegrid docs say that, "When we initialize the grid and the data is read, the datatype is automatically set to local." So, is it possible to implement local search with treeGrid. I tried the below configuration, but it is resulting in server calls. My Configuration is var grid = $("#grid").jqGrid({ treeGrid: true, treeGridModel: 'adjacency', ExpandColumn: 'businessAreaName', ExpandColClick : true, url:'agileProgramme/records.do', datatype: 'json', mtype: 'GET', colNames:['Id' , 'Business Area' , 'Investment' , 'Org' , 'Goal' ], colModel:[ /*00*/ {name:'agileProgrammeId',index:'agileProgrammeId', width:0, editable:false,hidden:true}, /*01*/ {name:'businessAreaName',index:'businessAreaName', width:160, editable:false}, /*02*/ {name:'programmeName',index:'programmeName', width:150, editable:false, classes:'link'}, /*03*/ {name:'org',index:'org', width:50, editable:false, classes:'orgHierarchy', sortable : false}, /*04*/ {name:'goal',index:'goal', width:70, editable:false} ], treeReader : { level_field: "level", parent_id_field: "parent", leaf_field: "leaf", expanded_field: "expanded" }, autowidth: true, height: 240, pager: '#pager', sortname: 'id', sortorder: "asc", toolbar:[true,"top"], caption:"TableGridDemo", emptyrecords: "Empty records", jsonReader : { root: "rows", page: "page", total: "total", records: "records", repeatitems: false, cell: "cell", id: "agileProgrammeId" } }); And to implement the search toolbar $('#grid').jqGrid('filterToolbar', {stringResult: true,searchOnEnter : true}); Would appreciate any help or any pointer on even if it is possible?

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  • iphone-AVAudio Player Crashes

    - by user2779450
    I have an app that uses an avaudio player for two things. One of them is to play an explosion sound when a uiimageview collision is detected, and the other is to play a lazer sound when a button is pressed. I declared the audioplayer in the .h class, and I call it each time the button is clicked by doing this: NSURL *url = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"/lazer" ofType:@"mp3"]]; NSError *error; audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:&error]; if (error) { NSLog(@"Error in audioPlayer: %@", [error localizedDescription]); } else { [audioPlayer prepareToPlay]; } [audioPlayer play]; This works fine, but after many uses of the game, the audio will stop play when i hit the button, and when a collision is detected, the game crashes. Here is my crash log: 2013-09-18 18:09:19.618 BattleShip[506:907] 18:09:19.617 shm_open failed: "AppleAudioQueue.41.2619" (23) flags=0x2 errno=24 (lldb) Suggestions? Could there be something to do with repeatedly creating an audio player? Alternatives maybe?

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  • C# reflexion, cloning

    - by Enriquev
    Say I have this class Myclass that contains this method: public class MyClass { public int MyProperty { get; set; } public int MySecondProperty { get; set; } public MyOtherClass subClass { get; set; } public object clone<T>(object original, T emptyObj) { FieldInfo[] fis = this.GetType().GetFields(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic); object tempMyClass = Activator.CreateInstance(typeof(T)); foreach (FieldInfo fi in fis) { if (fi.FieldType.Namespace != original.GetType().Namespace) fi.SetValue(tempMyClass, fi.GetValue(original)); else fi.SetValue(tempMyClass, this.clone(fi.GetValue(original), fi.GetValue(original))); } return tempMyClass; } } Then this class: public class MyOtherClass { public int MyProperty777 { get; set; } } when I do this: MyClass a = new MyClass { MyProperty = 1, MySecondProperty = 2, subClass = new MyOtherClass() { MyProperty777 = -1 } }; MyClass b = a.clone(a, a) as MyClass; how come on the second call to clone, T is of type object and not of type MyOtherClass

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  • Dynamic Linq Property Converting to Sql

    - by Matthew Hood
    I am trying to understand dynamic linq and expression trees. Very basically trying to do an equals supplying the column and value as strings. Here is what I have so far private IQueryable<tblTest> filterTest(string column, string value) { TestDataContext db = new TestDataContext(); // The IQueryable data to query. IQueryable<tblTest> queryableData = db.tblTests.AsQueryable(); // Compose the expression tree that represents the parameter to the predicate. ParameterExpression pe = Expression.Parameter(typeof(tblTest), "item"); Expression left = Expression.Property(pe, column); Expression right = Expression.Constant(value); Expression e1 = Expression.Equal(left, right); MethodCallExpression whereCallExpression = Expression.Call( typeof(Queryable), "Where", new Type[] { queryableData.ElementType }, queryableData.Expression, Expression.Lambda<Func<tblTest, bool>>(e1, new ParameterExpression[] { pe })); // Create an executable query from the expression tree. IQueryable<tblTest> results = queryableData.Provider.CreateQuery<tblTest>(whereCallExpression); return results; } That works fine for columns in the DB. But fails for properties in my code eg public partial class tblTest { public string name_test { get { return name; } } } Giving an error cannot be that it cannot be converted into SQL. I have tried rewriting the property as a Expression<Func but with no luck, how can I convert simple properties so they can be used with linq in this dynamic way? Many Thanks

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  • How to pull UIImages from NSData from a socket.

    - by Jus' Wondrin'
    Hey all! I'm using ASyncSocket to move some UIImages from one device over to another. Essentially, on one device I have: NSMutableData *data = UIImageJPEGRepresentation(image, 0.1); if(isRunning){ [sock writeData:data withTimeout:-1 tag:0]; } So a new image will be added to the socket every so often (like a webcam). Then, on the other device, I am calling: [listenSocket readDataWithTimeout:1 tag:0]; which will respond with: - (void)onSocket:(AsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag { [responseData appendData:data]; [listenSocket readDataWithTimeout:1 tag:0]; } Essentially, what I want to be able to do is have an NSTimer going which will call @selector(PullImages): -(void) PullImages { In here, I want to be able to pull images out of ResponseData. How do I do that? There might not be a complete image yet, there might be multiple images, there might be one and a half images! I want to parse the NSData into each existing image! } Any assistance? Thanks in advance!

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  • Observer pattern and violation of Single Principality Rule

    - by Devil Jin
    I have an applet which repaints itself once the text has changed Design 1: //MyApplet.java public class MyApplet extends Applet implements Listener{ private DynamicText text = null; public void init(){ text = new DynamicText("Welcome"); } public void paint(Graphics g){ g.drawString(text.getText(), 50, 30); } //implement Listener update() method public void update(){ repaint(); } } //DynamicText.java public class DynamicText implements Publisher{ // implements Publisher interface methods //notify listeners whenever text changes } Isn't this a violation of Single Responsibility Principle where my Applet not only acts as Applet but also has to do Listener job. Same way DynamicText class not only generates the dynamic text but updates the registered listeners. Design 2: //MyApplet.java public class MyApplet extends Applet{ private AppletListener appLstnr = null; public void init(){ appLstnr = new AppletListener(this); // applet stuff } } // AppletListener.java public class AppletListener implements Listener{ private Applet applet = null; public AppletListener(Applet applet){ this.applet = applet; } public void update(){ this.applet.repaint(); } } // DynamicText public class DynamicText{ private TextPublisher textPblshr = null; public DynamicText(TextPublisher txtPblshr){ this.textPblshr = txtPblshr; } // call textPblshr.notifyListeners whenever text changes } public class TextPublisher implments Publisher{ // implements publisher interface methods } Q1. Is design 1 a SPR violation? Q2. Is composition a better choice here to remove SPR violation as in design 2.

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  • Two-way data binding of controls in a user control inside a FormView

    - by Sandor Drieënhuizen
    I'm trying to perform two-way data binding on the controls in my user control, which is hosted inside a FormView template. FormView: <asp:ObjectDataSource runat="server" ID="ObjectDataSource" TypeName="WebApplication1.Data" SelectMethod="GetItem" UpdateMethod="UpdateItem"> </asp:ObjectDataSource> <asp:FormView runat="server" ID="FormView"> <ItemTemplate> <uc:WebUserControl1 runat="server"></uc:WebUserControl1> </ItemTemplate> <EditItemTemplate> <uc:WebUserControl1 runat="server"></uc:WebUserControl1> </EditItemTemplate> </asp:FormView> User control: <%@ Control Language="C#" ... %> <asp:TextBox runat="server" ID="TitleTextBox" Text='<%# Bind("Title") %>'> </asp:TextBox> The binding works fine when the FormView is in View mode but when I switch to Edit mode, upon calling UpdateItem on the FormView, the bindings are lost. I know this because the FormView tries to call an update method on the ObjectDataSource that does not have an argument called 'Title'. I tried to solve this by implementing IBindableTemplate to load the controls that are inside my user control, directly into the templates (just like I had entered them declaratively like in the code above). However, when calling UpdateItem in edit mode, the container that gets passed into the ExtractValues method of the template, does not contain the TextBox anymore. It did in view mode! I have found some questions on SO that relate to this problem but they are rather dated and don't provide straight forward answers. How do you think I could solve this problem? It seems to be such a simple requirement but apparently it's more like opening a can of worms...

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  • Microsoft OLE DB Provider for SQL Server error '80040e14' Could not find stored procedure

    - by BBlake
    I am migrating a classic ASP web app to new servers. The database back end is migrating from SQL Server 2000 to SQL Server 2008, and the app is moving from Win2000 x86 to Win2003R2 x64. I am getting the above error on every single stored procedure call within the application. I have verified: Yes, the SQL user is set up, using correct username and password Yes, the SQL user has execute permissions on the stored procedures in the database Yes, I have updated the TypeLib references to the new UUID Yes, I have logged into the database via SSMS with the SQL user id and it can see and execute the stored procedures just fine in SSMS, but not from the web app. Yes, the SQL user has the database set as its default database. The most frustrating thing is it works fine on the DEV server, but not on the production server. I have gone through every IIS setting 5 or 6 times and the web app is set up precisely the same in both environments. The only difference is the database server name in the connection string (DEV vs prod) EDIT: I have also tried pointing the prod web box at the dev database server and get the same error so I'm fairly sure the issue isn't on the database side.

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  • how to push different local git branches to heroku/master

    - by lsiden
    Heroku has a policy of ignoring all branches but 'master'. While I'm sure Heroku's designers have excellent reasons for for this policy (I'm guessing for storage and performance optimization), the consequence to me as a developer is that whatever local topic branch I may be working on, I would like an easy way to switch Heroku's master to that local topic branch and do a "git push heroku -f" to over-write master on Heroku. What I got from reading the "Pushing Refspecs" section of http://progit.org/book/ch9-5.html is git push -f heroku local-topic-branch:refs/heads/master What I'd really like is a way to set this up in the config file so that "git push heroku" always does the above, replacing local-topic-branch with the name of whatever my current branch happens to be. If anyone knows how to accomplish that, please let me know! The caveat for this, of course, is that this is only sensible if I am the only one who can push to that Heroku app/repository. A test or QA team might manage such a repository to try out different candidate branches, but they would have to coordinate so that they all agree on what branch they are pushing to it on any given day. Needless to say, it would also be a very good idea to have a separate remote repository (like Github) without this restriction for backing everything up to. I'd call that one "origin" and use "heroku" for Heroku so that "git push" always backs up everything to origin, and "git push heroku" pushes whatever branch I'm currently on to Heroku's master branch, overwriting it if necessary. Can anybody tell me if this would work? [remote "heroku"] url = [email protected]:my-app.git push = +refs/heads/*:refs/heads/master I'd like to hear from someone more experienced before I begin to experiment, although I suppose I could create a dummy app on Heroku and experiment with that. As for fetching, I don't really care if the Heroku repository is write-only. I still have a separate repository, like Github, for backup and cloning of all my work. Footnote: This question is similar to, but not quite the same as http://stackoverflow.com/questions/1489393/good-git-deployment-using-branches-strategy-with-heroku

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  • Threading is slow and unpredictable?

    - by Jake
    I've created the basis of a ray tracer, here's my testing function for drawing the scene: public void Trace(int start, int jump, Sphere testSphere) { for (int x = start; x < scene.SceneWidth; x += jump) { for (int y = 0; y < scene.SceneHeight; y++) { Ray fired = Ray.FireThroughPixel(scene, x, y); if (testSphere.Intersects(fired)) sceneRenderer.SetPixel(x, y, Color.Red); else sceneRenderer.SetPixel(x, y, Color.Black); } } } SetPixel simply sets a value in a single dimensional array of colours. If I call the function normally by just directly calling it it runs at a constant 55fps. If I do: Thread t1 = new Thread(() => Trace(0, 1, testSphere)); t1.Start(); t1.Join(); It runs at a constant 50fps which is fine and understandable, but when I do: Thread t1 = new Thread(() => Trace(0, 2, testSphere)); Thread t2 = new Thread(() => Trace(1, 2, testSphere)); t1.Start(); t2.Start(); t1.Join(); t2.Join(); It runs all over the place, rapidly moving between 30-40 fps and sometimes going out of that range up to 50 or down to 20, it's not constant at all. Why is it running slower than it would if I ran the whole thing on a single thread? I'm running on a quad core i5 2500k.

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  • Trying to build the basic python extension example fails (windows)

    - by Alexandros
    Hello, I have Python 2.6 and Visual Studio 2008 running on a Win7 x64 machine. When I try to build the basic python extension example in c "example_nt" as found in the python 2.6 sources distribution, it fails: python setup.py build And this results in: running build running build_ext building 'aspell' extension Traceback (most recent call last): File "setup.py", line 7, in <module> ext_modules = [module1]) File "C:\Python26\lib\distutils\core.py", line 152, in setup dist.run_commands() File "C:\Python26\lib\distutils\dist.py", line 975, in run_commands self.run_command(cmd) File "C:\Python26\lib\distutils\dist.py", line 995, in run_command cmd_obj.run() File "C:\Python26\lib\distutils\command\build.py", line 134, in run self.run_command(cmd_name) File "C:\Python26\lib\distutils\cmd.py", line 333, in run_command self.distribution.run_command(command) File "C:\Python26\lib\distutils\dist.py", line 995, in run_command cmd_obj.run() File "C:\Python26\lib\distutils\command\build_ext.py", line 343, in run self.build_extensions() File "C:\Python26\lib\distutils\command\build_ext.py", line 469, in build_extensions self.build_extension(ext) File "C:\Python26\lib\distutils\command\build_ext.py", line 534, in build_extension depends=ext.depends) File "C:\Python26\lib\distutils\msvc9compiler.py", line 448, in compile self.initialize() File "C:\Python26\lib\distutils\msvc9compiler.py", line 358, in initialize vc_env = query_vcvarsall(VERSION, plat_spec) File "C:\Python26\lib\distutils\msvc9compiler.py", line 274, in query_vcvarsall raise ValueError(str(list(result.keys()))) ValueError: [u'path'] What can I do to fix this? Any help will be appreciated

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  • Yahoo Account Has Been Closed

    - by VIVEK MISHRA
    My Domain www.manumachu.com had been closed by Yahoo due to non- Payment. I want to backorder it. is there anyway to do the following. This is the mail i received from Yahoo :- This is an automated notice. Replies to this address will not be received. If you have questions, please contact Yahoo! Customer Care. For your protection, Yahoo! will never ask you to provide your billing information via email. Dear Ravi Reddy manumachu, This notice is to inform you that your Yahoo! GeoCities Pro account has been closed due to nonpayment. The Yahoo! ID associated with this account: ravi_manumachu The domain name for this account: manumachu.com For questions, please visit our online help center or call our toll-free number at (800) 318-0870 between 6 a.m. and 6 p.m. PT, Monday through Friday, excluding holidays. Best regards, The Yahoo! Billing team This is a service email related to your use of Yahoo! Small Business. To learn more about Yahoo!'s use of personal information, including the use of web beacons in HTML-based email, please read our privacy policy. Yahoo! is located at 701 First Avenue, Sunnyvale, CA 94089. Copyright Policy - Terms of Service - Additional Terms - Help

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  • Malloc inside another function (ANSI C)

    - by Casper
    Hi I'll go straight to it. I'm working on an assignment, where I suddenly ran into trouble. I have to allocate a struct from within another function, obviously using pointers. I've been staring at this problem for hours and tried in a million different ways to solve it. This is some sample code (very simplified): ... some_struct s; printf("Before: %d\n", &s"); allocate(&s); printf("After: %d\n", &s"); ... /* The allocation function */ int allocate(some_struct *arg) { arg = malloc(sizeof(some_struct)); printf("In function: %d\n", &arg"); return 0; } This does give me the same address before and after the allocate-call: Before: -1079752900 In function: -1079752928 After: -1079752900 I know it's probably because it makes a copy in the function, but I don't know how to actually work on the pointer I gave as argument. I tried defining some_struct *s instead of some_struct s, but no luck. I tried with: int allocate(some_struct **arg) which works just fine (the allocate-function needs to be changed as well), BUT according to the assignment I may NOT change the declaration, and it HAS to be *arg.. And it would be most correct if I just have to declare some_struct s.. Not some_struct *s. I hope I make sense and some of you out there can help me :P Thanks in advice

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  • High-concurrency counters without sharding

    - by dound
    This question concerns two implementations of counters which are intended to scale without sharding (with a tradeoff that they might under-count in some situations): http://appengine-cookbook.appspot.com/recipe/high-concurrency-counters-without-sharding/ (the code in the comments) http://blog.notdot.net/2010/04/High-concurrency-counters-without-sharding My questions: With respect to #1: Running memcache.decr() in a deferred, transactional task seems like overkill. If memcache.decr() is done outside the transaction, I think the worst-case is the transaction fails and we miss counting whatever we decremented. Am I overlooking some other problem that could occur by doing this? What are the significiant tradeoffs between the two implementations? Here are the tradeoffs I see: #2 does not require datastore transactions. To get the counter's value, #2 requires a datastore fetch while with #1 typically only needs to do a memcache.get() and memcache.add(). When incrementing a counter, both call memcache.incr(). Periodically, #2 adds a task to the task queue while #1 transactionally performs a datastore get and put. #1 also always performs memcache.add() (to test whether it is time to persist the counter to the datastore). Conclusions (without actually running any performance tests): #1 should typically be faster at retrieving a counter (#1 memcache vs #2 datastore). Though #1 has to perform an extra memcache.add() too. However, #2 should be faster when updating counters (#1 datastore get+put vs #2 enqueue a task). On the other hand, with #1 you have to be a bit more careful with the update interval since the task queue quota is almost 100x smaller than either the datastore or memcahce APIs.

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  • purpose of 3rd party mvc ?

    - by Honey
    ive seen many third party mvcs or frameworks such as codeignitor , cakephp, and so on. what i want to know is what are their purposes? ive created my own framework call it an mvc or framework (in my opinion their all the same). in my framework i have all the classes in one folder called classes and all functions in another. its all organized and when a new project comes in i am able to complete it fast. i have looked at the applications that i mentioned and it seems to have huge articles and tutorials to study. what is the purpose? why not study the main language such as php, javascript/ajax or jquery, and so on then build something that you know the ins and outs of so that any project comes your way you know what to do. ive known some people who use cakephp and for every project they get stuck and need to figure out what to do. another guy i knew worked with joomla and every basic company website that came his way he would reverse engineer joomla to make it work with the site. are people using these applications because they lack knowledge in the languages? or sometimes have no choice but to make a site while lacking language and put something together.

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  • Not getting response using SOAP and PHP.

    - by Nitish
    I'm using PHP5 and NuSOAP - SOAP Toolkit for PHP. I created the server using the code below: <?php function getStockQuote($symbol) { mysql_connect('localhost','user','pass'); mysql_select_db('test'); $query = "SELECT stock_price FROM stockprices WHERE stock_symbol = '$symbol'"; $result = mysql_query($query); $row = mysql_fetch_assoc($result); echo $row['stock_price']; } $a=require('lib/nusoap.php'); $server = new soap_server(); $server->configureWSDL('stockserver', 'urn:stockquote'); $server->register("getStockQuote", array('symbol' => 'xsd:string'), array('return' => 'xsd:decimal'), 'urn:stockquote', 'urn:stockquote#getStockQuote'); $HTTP_RAW_POST_DATA = isset($HTTP_RAW_POST_DATA) ? $HTTP_RAW_POST_DATA : ''; $server->service($HTTP_RAW_POST_DATA); ?> The client has the following code: <?php require_once('lib/nusoap.php'); $c = new soapclientNusoap('http://localhost/stockserver.php?wsdl'); $stockprice = $c->call('getStockQuote', array('symbol' => 'ABC')); echo "The stock price for 'ABC' is $stockprice."; ?> The database was created using the code below: CREATE TABLE `stockprices` ( `stock_id` INT UNSIGNED NOT NULL AUTO_INCREMENT , `stock_symbol` CHAR( 3 ) NOT NULL , `stock_price` DECIMAL(8,2) NOT NULL , PRIMARY KEY ( `stock_id` ) ); INSERT INTO `stockprices` VALUES (1, 'ABC', '75.00'); INSERT INTO `stockprices` VALUES (2, 'DEF', '45.00'); INSERT INTO `stockprices` VALUES (3, 'GHI', '12.00'); INSERT INTO `stockprices` VALUES (4, 'JKL', '34.00'); When I run the client the result I get is this: The stock price for 'ABC' is . 75.00 is not being printed as the price.

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  • MS Access: Why is ADODB.Recordset.BatchUpdate so much slower than Application.ImportXML?

    - by apenwarr
    I'm trying to run the code below to insert a whole lot of records (from a file with a weird file format) into my Access 2003 database from VBA. After many, many experiments, this code is the fastest I've been able to come up with: it does 10000 records in about 15 seconds on my machine. At least 14.5 of those seconds (ie. almost all the time) is in the single call to UpdateBatch. I've read elsewhere that the JET engine doesn't support UpdateBatch. So maybe there's a better way to do it. Now, I would just think the JET engine is plain slow, but that can't be it. After generating the 'testy' table with the code below, I right clicked it, picked Export, and saved it as XML. Then I right clicked, picked Import, and reloaded the XML. Total time to import the XML file? Less than one second, ie. at least 15x faster. Surely there's an efficient way to insert data into Access that doesn't require writing a temp file? Sub TestBatchUpdate() CurrentDb.Execute "create table testy (x int, y int)" Dim rs As New ADODB.Recordset rs.CursorLocation = adUseServer rs.Open "testy", CurrentProject.AccessConnection, _ adOpenStatic, adLockBatchOptimistic, adCmdTableDirect Dim n, v n = Array(0, 1) v = Array(50, 55) Debug.Print "starting loop", Time For i = 1 To 10000 rs.AddNew n, v Next i Debug.Print "done loop", Time rs.UpdateBatch Debug.Print "done update", Time CurrentDb.Execute "drop table testy" End Sub I would be willing to resort to C/C++ if there's some API that would let me do fast inserts that way. But I can't seem to find it. It can't be that Application.ImportXML is using undocumented APIs, can it?

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  • #Error showing up in multiple LEFT JOIN statement Access query when value should be NULL

    - by lar
    I'm trying to return an ID's last 4 years of data, if existing. The table (call it A_TABLE) looks like this: ID, Year, Val The idea behind the query is this: for each ID/Year in the table, LEFT JOIN with Year-1, Year-2, and Year-3 (to get 4 years of data) and then return Val for each year. Here's the SQL: SELECT a.ID, a.year AS [Year], a.Val AS VAL, a1.year AS [Year-1], a1.Val AS [VAL-1], a2.year AS [Year-2], a2.Val AS [VAL-2], a3.year AS [Year-3], a3.Val AS [VAL-3] FROM ( ([A_TABLE] AS a LEFT JOIN [A_TABLE] AS a1 ON (a.ID = a1.ID) AND (a.year = a1.year+1)) LEFT JOIN [A_TABLE] AS a2 ON (a.ID = a2.ID) AND (a.year = a2.year+2)) LEFT JOIN [A_TABLE] AS a3 ON (a.ID = a3.ID) AND (a.year = a3.year+3) The problem is that, for past years where there is no data (eg, Year-1), I see "#Error" in the appropriate VAL column (eg, [VAL-1]). The weird thing is, I see the expected "null" in the Year column (eg, [YEAR-1]). Some sample data: ID YEAR VAL Dave 2004 1 Dave 2006 2 Dave 2007 3 Dave 2008 5 Dave 2009 0 outputs like this: ID YEAR VAL YEAR-1 VAL-1 YEAR-2 VAL-2 YEAR-3 VAL-3 Dave 2004 1 #Error #Error #Error Dave 2006 2 #Error 2004 1 #Error Dave 2007 3 2006 2 #Error 2004 1 Dave 2008 5 2007 3 2006 2 #Error Dave 2009 0 2008 5 2007 3 2006 2 Does that make sense? Why am I getting the appropriate NULL val for the non-existent YEARs, but an #Error for the non-existent VALs? (This is Access 2000. Conditional statements like "IIf(a1.val is null, -999, a1.val)" do not seem to do anything.) EDIT: It turns out that the errors are somehow caused by the fact that A_TABLE is actually a query. When I put all the data into an actual table and run the same query, everything shows up as it should. Thanks for the help, everyone.

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  • exception message getting lost in IIOP between glassfish domains

    - by Michael Borgwardt
    I'm running two glassfish v2 domains containing stateless session EJBs. In a few cases, an EJB in one domain has to call one in the other. My problem is that when the called EJB aborts with an exception, the caller does not receive the message of the exception and instead reports an internal error that is not helpful at all in diagnosing the problem. What happens seems to be this: At the transport layer, a org.omg.CORBA.portable.ApplicationException is created,which already loses all detail information about the exception except its class. Inside com.sun.jts.CosTransactions.TopCoordinator.get_txcontext(), the status of the transaction ass rolled back causes a org.omg.CosTransactions.Unavailable to be thrown, which gets wrapped and passed around a few times and eventually results into this error being displayed to the user: org.omg.CORBA.INVALID_TRANSACTION: vmcid: 0x0 minor code: 0 completed: No at com.sun.jts.CosTransactions.CurrentTransaction.sendingRequest(CurrentTransaction.java:807) at com.sun.jts.CosTransactions.SenderReceiver.sending_request(SenderReceiver.java:139) at com.sun.jts.pi.InterceptorImpl.send_request(InterceptorImpl.java:344) at com.sun.corba.ee.impl.interceptors.InterceptorInvoker.invokeClientInterceptorStartingPoint(InterceptorInvoker.java:271) at com.sun.corba.ee.impl.interceptors.PIHandlerImpl.invokeClientPIStartingPoint(PIHandlerImpl.java:348) at com.sun.corba.ee.impl.protocol.CorbaClientRequestDispatcherImpl.beginRequest(CorbaClientRequestDispatcherImpl.java:284) at com.sun.corba.ee.impl.protocol.CorbaClientDelegateImpl.request(CorbaClientDelegateImpl.java:184) at com.sun.corba.ee.impl.presentation.rmi.StubInvocationHandlerImpl.privateInvoke(StubInvocationHandlerImpl.java:186) at com.sun.corba.ee.impl.presentation.rmi.StubInvocationHandlerImpl.invoke(StubInvocationHandlerImpl.java:152) at com.sun.corba.ee.impl.presentation.rmi.bcel.BCELStubBase.invoke(BCELStubBase.java:225) Is there anything I can do here to preserve information about the actual cause of the problem?

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  • eventmachine and external scripts via backticks

    - by Maciek
    I have a small HTTP server script I've written using eventmachine which needs to call external scripts/commands and does so via backticks (``). When serving up requests which don't run backticked code, everything is fine, however, as soon as my EM code executes any backticked external script, it stops serving requests and stops executing in general. I noticed eventmachine seems to be sensitive to sub-processes and/or threads, and appears to have the popen method for this purpose, but EM's source warns that this method doesn't work under Windows. Many of the machines running this script are running Windows, so I can't use popen. Am I out of luck here? Is there a safe way to run an external command from an eventmachine script under Windows? Is there any way I could fire off some commands to be run externally without blocking EM's execution? edit: the culprit that seems to be screwing up EM the most is my usage of the Windows start command, as in: start java myclass. The reason I'm using start is because I want those external scripts to start running and keep running after the EM request is served

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