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  • Internet Explorer and onMouseOver/onMouseOut

    - by Thorbjørn Reimann-Andersen
    Hi all, I have tried looking a similar question on here but couldnt find one so here it comes: I have this html (ignore the "+whatever+@", its in a codebehind file so im putting some variables that im getting from there): <div id='ReferenceContainer"+UniqueID+@"' style='background-color:"+BackcolourOFF+@"; width:"+CompWidth+@"; height:"+CompHeight+@";'> <div id='Reference"+UniqueID+@"' style='width:"+CompWidth+@"; height:"+CompHeight+@"; '> <div id='RefTextContainer"+UniqueID+@"' style='float:left; width:"+CompWidth+@"; height:"+CompHeight+@"; ' > <div id='RefTitleCon' style='margin-top:"+RefTitleMargin+@"px; color:"+RefTitleColor+@"; z-index:-1;' ><p><b>"+RefTitle+@"</b></p> </div> <div id='RefTextCon'><p>"+RefText+@"</p></div> </div> <div id='RefPicContainer"+UniqueID+@"' style='float:right;'> <img id='RefImg"+UniqueID+@"first' class='first' name='RefImg"+UniqueID+@"' src=" + StartImg + @" style='position:absolute;' ></img> <img id='RefImg"+UniqueID+@"second' class='second' name='RefImg"+UniqueID+@"' src=" + AltImg + @" style='display:none;' ></img> </div> </div> <div id='ScriptContainer"+UniqueID+@"' style='width:"+CompWidth+@"; height:"+CompHeight+@"; position:relative; top:-"+CompHeight+@"px; left:0px;' onMouseOver='ChangeBackcolourON"+UniqueID+@"()' onMouseOut='ChangeBackcolourOFF"+UniqueID+@"()'></div> </div> Now in firefox, everything works just perfect. The div "ScriptContainer" sits in front of the whole thing and when the mouse enters or leaves the functions work exactly as they should. But IE8 places the text in front of everything and then the functions do not work as i would like them to. "ChangeBackcolourOFF" gets called every time the mouse enters the text, which sits in front of everything and "ChangeBackcolourON" gets called every time the mouse enters the "Scriptcontainer" from the text. So i either need to figure out how to force the text to be placed behind the "Scriptcontainer" or some other solutions. I appreciate you answers

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  • Reverse proxy for a REST web service using ADFS/AD and WebApi

    - by Kai Friis
    I need to implement a reverse proxy for a REST webservice behind a firewall. The reverse proxy should authenticate against an enterprise ADFS 2.0 server, preferably using claims in .net 4.5. The clients will be a mix of iOS, Android and web. I’m completely new to this topic; I’ve tried to implement the service as a REST service using WebApi, WIF and the new Identity and Access control in VS 2012, with no luck. I have also tried to look into Brock Allen’s Thinktecture.IdentityModel.45, however then my head was spinning so I didn’t see the difference between it and Windows Identity Foundation with the Identity and Access control. So I think I need to step back and get some advice on how to do this. There are several ways to this, as far as I understand it. In hardware. Set up our Citrix Netscaler as a reverse proxy. I have no idea how to do that, however if it’s a good solution I can always hire someone who knows… Do it in the webserver, like IIS. I haven’t tried it; do not know if it will work. Create a web service to do it. 3.1 Implement it as a SOAP service using WCF. As I understand it ADFS do not support REST so I have to use SOAP. The problem is mobile device do not like SOAP, neither do I… However if it’s the best way, I have to do it. 3.2 Use Azure Access Control Service. It might work, however the timing is not good. Our enterprise is considering several cloud options, and us jumping on the azure wagon on our own might not be the smartest thing to do right now. However if it is the only options, we can do it. I just prefer not to use it right now. Right now I feel there are too many options, and I do not know which one will work. If someone can point me in the right directions, which path to pursue, I would be very grateful.

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  • Silverlight with MVVM Inheritance: ModelView and View matching the Model

    - by moonground.de
    Hello Stackoverflowers! :) Today I have a special question on Silverlight (4 RC) MVVM and inheritance concepts and looking for a best practice solution... I think that i understand the basic idea and concepts behind MVVM. My Model doesn't know anything about the ViewModel as the ViewModel itself doesn't know about the View. The ViewModel knows the Model and the Views know the ViewModels. Imagine the following basic (example) scenario (I'm trying to keep anything short and simple): My Model contains a ProductBase class with a few basic properties, a SimpleProduct : ProductBase adding a few more Properties and ExtendedProduct : ProductBase adding another properties. According to this Model I have several ViewModels, most essential SimpleProductViewModel : ViewModelBase and ExtendedProductViewModel : ViewModelBase. Last but not least, according Views SimpleProductView and ExtendedProductView. In future, I might add many product types (and matching Views + VMs). 1. How do i know which ViewModel to create when receiving a Model collection? After calling my data provider method, it will finally end up having a List<ProductBase>. It containts, for example, one SimpleProduct and two ExtendedProducts. How can I transform the results to an ObservableCollection<ViewModelBase> having the proper ViewModel types (one SimpleProductViewModel and two ExtendedProductViewModels) in it? I might check for Model type and construct the ViewModel accordingly, i.e. foreach(ProductBase currentProductBase in resultList) if (currentProductBase is SimpleProduct) viewModels.Add( new SimpleProductViewModel((SimpleProduct)currentProductBase)); else if (currentProductBase is ExtendedProduct) viewModels.Add( new ExtendedProductViewModels((ExtendedProduct)currentProductBase)); ... } ...but I consider this very bad practice as this code doesn't follow the object oriented design. The other way round, providing abstract Factory methods would reduce the code to: foreach(ProductBase currentProductBase in resultList) viewModels.Add(currentProductBase.CreateViewModel()) and would be perfectly extensible but since the Model doesn't know the ViewModels, that's not possible. I might bring interfaces into game here, but I haven't seen such approach proven yet. 2. How do i know which View to display when selecting a ViewModel? This is pretty the same problem, but on a higher level. Ended up finally having the desired ObservableCollection<ViewModelBase> collection would require the main view to choose a matching View for the ViewModel. In WPF, there is a DataTemplate concept which can supply a View upon a defined DataType. Unfortunately, this doesn't work in Silverlight and the only replacement I've found was the ResourceSelector of the SLExtensions toolkit which is buggy and not satisfying. Beside that, all problems from Question 1 apply as well. Do you have some hints or even a solution for the problems I describe, which you hopefully can understand from my explanation? Thank you in advance! Thomas

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  • Why does SFINAE not apply to this?

    - by Simon Buchan
    I'm writing some simple point code while trying out Visual Studio 10 (Beta 2), and I've hit this code where I would expect SFINAE to kick in, but it seems not to: template<typename T> struct point { T x, y; point(T x, T y) : x(x), y(y) {} }; template<typename T, typename U> struct op_div { typedef decltype(T() / U()) type; }; template<typename T, typename U> point<typename op_div<T, U>::type> operator/(point<T> const& l, point<U> const& r) { return point<typename op_div<T, U>::type>(l.x / r.x, l.y / r.y); } template<typename T, typename U> point<typename op_div<T, U>::type> operator/(point<T> const& l, U const& r) { return point<typename op_div<T, U>::type>(l.x / r, l.y / r); } int main() { point<int>(0, 1) / point<float>(2, 3); } This gives error C2512: 'point<T>::point' : no appropriate default constructor available Given that it is a beta, I did a quick sanity check with the online comeau compiler, and it agrees with an identical error, so it seems this behavior is correct, but I can't see why. In this case some workarounds are to simply inline the decltype(T() / U()), to give the point class a default constructor, or to use decltype on the full result expression, but I got this error while trying to simplify an error I was getting with a version of op_div that did not require a default constructor*, so I would rather fix my understanding of C++ rather than to just do what works. Thanks! *: the original: template<typename T, typename U> struct op_div { static T t(); static U u(); typedef decltype(t() / u()) type; }; Which gives error C2784: 'point<op_div<T,U>::type> operator /(const point<T> &,const U &)' : could not deduce template argument for 'const point<T> &' from 'int', and also for the point<T> / point<U> overload.

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  • Understanding SingleTableEntityPersister n QueryLoader

    - by Iapilgrim
    Hi, I have the Hibernate model @Cache(usage = CacheConcurrencyStrategy.NONE, region = SitesConstants.CACHE_REGION) public class Node extends StatefulEntity implements Inheritable, Cloneable { private Node _parent; private List<Node> _childNodes; .. } @Cache(usage = CacheConcurrencyStrategy.NONE, region = SitesConstants.CACHE_REGION) public class Page extends Node implements Defaultable, Securable { private RootZone _rootZone; ...... @OneToOne(fetch = FetchType.LAZY) @JoinColumn(name = "root_zone_id", insertable = false, updatable = false) public RootZone getRootZone() { return _rootZone; } public void setRootZone(RootZone rootZone) { if (rootZone != null) { rootZone.setPageId(this.getId()); _rootZone = rootZone; } } I want to get all pages ( call getSiteTree), so I using this query String hpql = "SELECT n FROM Node n "; See the trace I find Page.setRootZone(RootZone) line: 155 NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not available [native method] NativeMethodAccessorImpl.invoke(Object, Object[]) line: 39 DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: 25 Method.invoke(Object, Object...) line: 597 BasicPropertyAccessor$BasicSetter.set(Object, Object, SessionFactoryImplementor) line: 66 PojoEntityTuplizer(AbstractEntityTuplizer).setPropertyValues(Object, Object[]) line: 352 PojoEntityTuplizer.setPropertyValues(Object, Object[]) line: 232 SingleTableEntityPersister(AbstractEntityPersister).setPropertyValues(Object, Object[], EntityMode) line: 3580 TwoPhaseLoad.initializeEntity(Object, boolean, SessionImplementor, PreLoadEvent, PostLoadEvent) line: 152 QueryLoader(Loader).initializeEntitiesAndCollections(List, Object, SessionImplementor, boolean) line: 877 QueryLoader(Loader).doQuery(SessionImplementor, QueryParameters, boolean) line: 752 QueryLoader(Loader).doQueryAndInitializeNonLazyCollections(SessionImplementor, QueryParameters, boolean) line: 259 QueryLoader(Loader).doList(SessionImplementor, QueryParameters) line: 2232 QueryLoader(Loader).listIgnoreQueryCache(SessionImplementor, QueryParameters) line: 2129 QueryLoader(Loader).list(SessionImplementor, QueryParameters, Set, Type[]) line: 2124 QueryLoader.list(SessionImplementor, QueryParameters) line: 401 QueryTranslatorImpl.list(SessionImplementor, QueryParameters) line: 363 HQLQueryPlan.performList(QueryParameters, SessionImplementor) line: 196 SessionImpl.list(String, QueryParameters) line: 1149 QueryImpl.list() line: 102 QueryImpl.getResultList() line: 67 NodeDaoImpl.getSiteTree(long) line: 358 PageNodeServiceImpl.getSiteTree(long) line: 797 NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not available [native method] NativeMethodAccessorImpl.invoke(Object, Object[]) line: 39 DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: 25 Method.invoke(Object, Object...) line: 597 AopUtils.invokeJoinpointUsingReflection(Object, Method, Object[]) line: 307 JdkDynamicAopProxy.invoke(Object, Method, Object[]) line: 198 $Proxy100.getSiteTree(long) line: not available the calling setRootZone in Page makes Hibernate issue a hit to database. I don't want this. So my question is + Why query String hpql = "SELECT n FROM Node n "; issues un-expected trace logs like above. Why the query String hpql = "SELECT n.nodename FROM Node n " not? What is the mechanism behind? Note: Im using hibernate caching level 2. In case I don't want to see that trace logs. I mean I just get Node data only. How to do ? Thanks for your help. Sorry for my bad english :( Van

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  • Where can I find information on the Get, Set and Address methods for multidimensional System.Array i

    - by Rob Smallshire
    System.Array serves as the base class for all arrays in the Common Language Runtime (CLR). According to this article, For each concrete array type, [the] runtime adds three special methods: Get/Set/Address. and indeed if I disassemble this C# code, int[,] x = new int[1024,1024]; x[0,0] = 1; x[1,1] = 2; x[2,2] = 3; Console.WriteLine(x[0,0]); Console.WriteLine(x[1,1]); Console.WriteLine(x[2,2]); into CIL I get, IL_0000: ldc.i4 0x400 IL_0005: ldc.i4 0x400 IL_000a: newobj instance void int32[0...,0...]::.ctor(int32, int32) IL_000f: stloc.0 IL_0010: ldloc.0 IL_0011: ldc.i4.0 IL_0012: ldc.i4.0 IL_0013: ldc.i4.1 IL_0014: call instance void int32[0...,0...]::Set(int32, int32, int32) IL_0019: ldloc.0 IL_001a: ldc.i4.1 IL_001b: ldc.i4.1 IL_001c: ldc.i4.2 IL_001d: call instance void int32[0...,0...]::Set(int32, int32, int32) IL_0022: ldloc.0 IL_0023: ldc.i4.2 IL_0024: ldc.i4.2 IL_0025: ldc.i4.3 IL_0026: call instance void int32[0...,0...]::Set(int32, int32, int32) IL_002b: ldloc.0 IL_002c: ldc.i4.0 IL_002d: ldc.i4.0 IL_002e: call instance int32 int32[0...,0...]::Get(int32, int32) IL_0033: call void [mscorlib]System.Console::WriteLine(int32) IL_0038: ldloc.0 IL_0039: ldc.i4.1 IL_003a: ldc.i4.1 IL_003b: call instance int32 int32[0...,0...]::Get(int32, int32) IL_0040: call void [mscorlib]System.Console::WriteLine(int32) IL_0045: ldloc.0 IL_0046: ldc.i4.2 IL_0047: ldc.i4.2 IL_0048: call instance int32 int32[0...,0...]::Get(int32, int32) IL_004d: call void [mscorlib]System.Console::WriteLine(int32) where the calls to the aforementioned Get and Set methods can be clearly seen. It seems the arity of these methods is related to the dimensionality of the array, which is presumably why they are created by the runtime and are not pre-declared. I couldn't locate any information about these methods on MSDN and their simple names makes them resistant to Googling. I'm writing a compiler for a language which supports multidimensional arrays, so I'd like to find some official documentation about these methods, under what conditions I can expect them to exist and what I can expect their signatures to be. In particular, I'd like to know whether its possible to get a MethodInfo object for Get or Set for use with Reflection.Emit without having to create an instance of the array with correct type and dimensionality on which to reflect, as is done in the linked example.

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  • If Then Statement Condition Being Ignored With Optimisations On

    - by Matma
    I think im going mad but can some show me what im missing, it must be some stupidly simple i just cant see the wood for the trees. BOTH side of this if then else statement are being executed? Ive tried commenting out the true side and moving the condition to a seperate variable with the same result. However if i explicitly set the condition to 1=0 or 1=1 then the if then statement is operating as i would expect. i.e. only executing one side of the equation... The only time ive seen this sort of thing is when the compiler has crashed and is no longer compiling (without visible indication that its not) but ive restarted studio with the same results, ive cleaned the solution, built and rebuilt with no change? please show me the stupid mistake im making using vs2005 if it matters. Dim dset As DataSet = New DataSet If (CboCustomers.SelectedValue IsNot Nothing) AndAlso (CboCustomers.SelectedValue <> "") Then Dim Sql As String = "Select sal.SalesOrderNo As SalesOrder,cus.CustomerName,has.SerialNo, convert(varchar,sal.Dateofpurchase,103) as Date from [dbo].[Customer_Table] as cus " & _ " inner join [dbo].[Hasp_table] as has on has.CustomerID=cus.CustomerTag " & _ " inner join [dbo].[salesorder_table] as sal On sal.Hasp_ID =has.Hasp_ID Where cus.CustomerTag = '" & CboCustomers.SelectedValue.ToString & "'" Dim dap As SqlDataAdapter = New SqlDataAdapter(Sql, FormConnection) dap.Fill(dset, "dbo.Customer_Table") DGCustomer.DataSource = dset.Tables("dbo.Customer_Table") Else Dim erm As String = "wtf" End If EDIT: i have found that this is something to do with the release config settings im using, i guesing its the optimisations bit. does anyone know of any utils/addons for vs that show if a line has been optimised out. delphi, my former language showed blue dots in the left margin to show that it was a compiled line, no dot meaning it wasnt compiled in, is there anything like that for vs? alternatively can someone explain how optimisations would affect this simple if statement causeing it to run both sides? EDIT2: using this thread as possible causes/solutions : http://stackoverflow.com/questions/2135509/bug-only-occurring-when-compile-optimization-enabled. It does the same with release = optimisations on, x86, x64 and AnyCPU Goes away with optimisations off. Im using V2005 on a x64 win7 machine, if that matters. Thanks

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  • Load on page inside another onClick

    - by Robin I Knight
    Hello, I need to include the content, scripts, forms and dynamic abilities of one page in another onClick. Take a look at http://www.divethegap.com/scuba-diving-programmes-dive-the-gap/dahab-master-scuba-diver.html Then follow one of the links that says 'Beginner' 'Open Water Diver' etc.... You will find a PHP page with a series of options. It is an adaption of the wordpress blog system to produce only specific options for specific programmes by considering each type of each diving programme a category and then displaying only results from that category. You will see that each option is also a collapsible panel and there are also several javascripts that calculate durations, quantities and prices. There is also a validating webform at the end. Now go back to the first page. What I would like to do is include all the content from the second page after the main header inside tabbed panels on the first page so that the customers can immidietly see everything that is included. Essentially the options on the first page would become a series of tabs. The only way I can see to do this is with an iFrame as each option would need a unique URL ending (that is .php?cat=26 or .php?cat=27). THe problem is that the collapsible panels will not work with an iFrame as the iFrame will not resize when the panels open. There were also some calculation problems, but I think that was more down to me staring at the screen for the last 3 hours not remembering to include everything. I have tried it with resizing iframe SSI scripts and have got nowhere. I tried actually embedding it in the page better with a ajax script, but that left behind all the scripts that make it work. I checked with full URL's on everything and it would not take work with any scripts. I know that you could just make the whole page reload but then the user would be at the top of the page again, and even if another script was applied to slowly bring them down again it would not be anything near as easy to use as if it was like tabbed panels. Any ideas. Kind Regards,

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  • Contact Bubble EditText

    - by toobsco42
    I am trying to create contact bubbles in the MultiAutoCompleteTextView similiar to how it is implemented in the Google+ app. Below is a screen shot: . I have tried to extend the DynamicDrawableSpan class in order to get a spannable drawable in the background of a span of text public class BubbleSpan extends DynamicDrawableSpan { private Context c; public BubbleSpan(Context context) { super(); c = context; } @Override public Drawable getDrawable() { Resources res = c.getResources(); Drawable d = res.getDrawable(R.drawable.oval); d.setBounds(0, 0, 100, 20); return d; } } Where my oval.xml drawable is defined as so: <?xml version="1.0" encoding="utf-8"?> <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="oval"> <solid android:color="#00000000"/> <stroke android:width="4dp" android:color="#99000000" android:dashWidth="4dp" android:dashGap="2dp" /> <padding android:left="7dp" android:top="7dp" android:right="7dp" android:bottom="7dp" /> <corners android:radius="4dp" /> </shape> In my Activity class that has the MulitAutoCompleteTextView, I set the bubble span like so: final Editable e = tv.getEditableText(); final SpannableStringBuilder sb = new SpannableStringBuilder(); sb.append("some sample text"); sb.setSpan(new BubbleSpan(getApplicationContext()), 0, 6, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE); e.append(sb); However, instead of the oval shape displaying behind the first 6 characters in the string, the characters are not visible and there is no oval drawable in the background. If i change the BubbleSpan's getDrawable() method to use a .png instead of a shape drawable: public Drawable getDrawable() { Resources res = c.getResources(); Drawable d = res.getDrawable(android.R.drawable.bottom_bar); d.setBounds(0, 0, 100, 20); return d; } Then the .png will show up but the characters in the string that are a part of the span will not show up. How can I make it so that the characters in the span are displayed in the foreground, meanwhile a custom shape drawable gets displayed in the background? I attempted to also use an ImageSpan instead of subclassing DynamicDrawableSpan but was unsuccessful.

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  • How to combine designable components with dependency injection

    - by Wim Coenen
    When creating a designable .NET component, you are required to provide a default constructor. From the IComponent documentation: To be a component, a class must implement the IComponent interface and provide a basic constructor that requires no parameters or a single parameter of type IContainer. This makes it impossible to do dependency injection via constructor arguments. (Extra constructors could be provided, but the designer would ignore them.) Some alternatives we're considering: Service Locator Don't use dependency injection, instead use the service locator pattern to acquire dependencies. This seems to be what IComponent.Site.GetService is for. I guess we could create a reusable ISite implementation (ConfigurableServiceLocator?) which can be configured with the necessary dependencies. But how does this work in a designer context? Dependency Injection via properties Inject dependencies via properties. Provide default instances if they are necessary to show the component in a designer. Document which properties need to be injected. Inject dependencies with an Initialize method This is much like injection via properties but it keeps the list of dependencies that need to be injected in one place. This way the list of required dependencies is documented implicitly, and the compiler will assists you with errors when the list changes. Any idea what the best practice is here? How do you do it? edit: I have removed "(e.g. a WinForms UserControl)" since I intended the question to be about components in general. Components are all about inversion of control (see section 8.3.1 of the UMLv2 specification) so I don't think that "you shouldn't inject any services" is a good answer. edit 2: It took some playing with WPF and the MVVM pattern to finally "get" Mark's answer. I see now that visual controls are indeed a special case. As for using non-visual components on designer surfaces, I think the .NET component model is fundamentally incompatible with dependency injection. It appears to be designed around the service locator pattern instead. Maybe this will start to change with the infrastructure that was added in .NET 4.0 in the System.ComponentModel.Composition namespace.

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  • CUDA, more threads for same work = Longer run time despite better occupancy, Why?

    - by zenna
    I encountered a strange problem where increasing my occupancy by increasing the number of threads reduced performance. I created the following program to illustrate the problem: #include <stdio.h> #include <stdlib.h> #include <cuda_runtime.h> __global__ void less_threads(float * d_out) { int num_inliers; for (int j=0;j<800;++j) { //Do 12 computations num_inliers += threadIdx.x*1; num_inliers += threadIdx.x*2; num_inliers += threadIdx.x*3; num_inliers += threadIdx.x*4; num_inliers += threadIdx.x*5; num_inliers += threadIdx.x*6; num_inliers += threadIdx.x*7; num_inliers += threadIdx.x*8; num_inliers += threadIdx.x*9; num_inliers += threadIdx.x*10; num_inliers += threadIdx.x*11; num_inliers += threadIdx.x*12; } if (threadIdx.x == -1) d_out[blockIdx.x*blockDim.x+threadIdx.x] = num_inliers; } __global__ void more_threads(float *d_out) { int num_inliers; for (int j=0;j<800;++j) { // Do 4 computations num_inliers += threadIdx.x*1; num_inliers += threadIdx.x*2; num_inliers += threadIdx.x*3; num_inliers += threadIdx.x*4; } if (threadIdx.x == -1) d_out[blockIdx.x*blockDim.x+threadIdx.x] = num_inliers; } int main(int argc, char* argv[]) { float *d_out = NULL; cudaMalloc((void**)&d_out,sizeof(float)*25000); more_threads<<<780,128>>>(d_out); less_threads<<<780,32>>>(d_out); return 0; } Note both kernels should do the same amount of work in total, the (if threadIdx.x == -1 is a trick to stop the compiler optimising everything out and leaving an empty kernel). The work should be the same as more_threads is using 4 times as many threads but with each thread doing 4 times less work. Significant results form the profiler results are as followsL: more_threads: GPU runtime = 1474 us,reg per thread = 6,occupancy=1,branch=83746,divergent_branch = 26,instructions = 584065,gst request=1084552 less_threads: GPU runtime = 921 us,reg per thread = 14,occupancy=0.25,branch=20956,divergent_branch = 26,instructions = 312663,gst request=677381 As I said previously, the run time of the kernel using more threads is longer, this could be due to the increased number of instructions. Why are there more instructions? Why is there any branching, let alone divergent branching, considering there is no conditional code? Why are there any gst requests when there is no global memory access? What is going on here! Thanks

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  • Django Multi-Table Inheritance VS Specifying Explicit OneToOne Relationship in Models

    - by chefsmart
    Hope all this makes sense :) I'll clarify via comments if necessary. Also, I am experimenting using bold text in this question, and will edit it out if I (or you) find it distracting. With that out of the way... Using django.contrib.auth gives us User and Group, among other useful things that I can't do without (like basic messaging). In my app I have several different types of users. A user can be of only one type. That would easily be handled by groups, with a little extra care. However, these different users are related to each other in hierarchies / relationships. Let's take a look at these users: - Principals - "top level" users Administrators - each administrator reports to a Principal Coordinators - each coordinator reports to an Administrator Apart from these there are other user types that are not directly related, but may get related later on. For example, "Company" is another type of user, and can have various "Products", and products may be supervised by a "Coordinator". "Buyer" is another kind of user that may buy products. Now all these users have various other attributes, some of which are common to all types of users and some of which are distinct only to one user type. For example, all types of users have to have an address. On the other hand, only the Principal user belongs to a "BranchOffice". Another point, which was stated above, is that a User can only ever be of one type. The app also needs to keep track of who created and/or modified Principals, Administrators, Coordinators, Companies, Products etc. (So that's two more links to the User model.) In this scenario, is it a good idea to use Django's multi-table inheritance as follows: - from django.contrib.auth.models import User class Principal(User): # # # branchoffice = models.ForeignKey(BranchOffice) landline = models.CharField(blank=True, max_length=20) mobile = models.CharField(blank=True, max_length=20) created_by = models.ForeignKey(User, editable=False, blank=True, related_name="principalcreator") modified_by = models.ForeignKey(User, editable=False, blank=True, related_name="principalmodifier") # # # Or should I go about doing it like this: - class Principal(models.Model): # # # user = models.OneToOneField(User, blank=True) branchoffice = models.ForeignKey(BranchOffice) landline = models.CharField(blank=True, max_length=20) mobile = models.CharField(blank=True, max_length=20) created_by = models.ForeignKey(User, editable=False, blank=True, related_name="principalcreator") modified_by = models.ForeignKey(User, editable=False, blank=True, related_name="principalmodifier") # # # Please keep in mind that there are other user types that are related via foreign keys, for example: - class Administrator(models.Model): # # # principal = models.ForeignKey(Principal, help_text="The supervising principal for this Administrator") user = models.OneToOneField(User, blank=True) province = models.ForeignKey( Province) landline = models.CharField(blank=True, max_length=20) mobile = models.CharField(blank=True, max_length=20) created_by = models.ForeignKey(User, editable=False, blank=True, related_name="administratorcreator") modified_by = models.ForeignKey(User, editable=False, blank=True, related_name="administratormodifier") I am aware that Django does use a one-to-one relationship for multi-table inheritance behind the scenes. I am just not qualified enough to decide which is a more sound approach.

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  • Add new row to asp .net grid view using button

    - by SARAVAN
    Hi, I am working in ASP .net 2.0. I am a learner. I have a grid view which has a button in it. Please find the asp mark up below <form id="form1" runat="server"> <div> <asp:GridView ID="myGridView" runat="server"> <Columns> <asp:TemplateField> <ItemTemplate> <asp:Button CommandName="AddARowBelow" Text="Add A Row Below" runat="server" /> </ItemTemplate> </asp:TemplateField> </Columns> </asp:GridView> </div> </form> Please find the code behind below. using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Data; using System.Web.UI.WebControls; namespace GridViewDemo { public partial class _Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { DataTable dt = new DataTable("myTable"); dt.Columns.Add("col1"); dt.Columns.Add("col2"); dt.Columns.Add("col3"); dt.Rows.Add(1, 2, 3); dt.Rows.Add(1, 2, 3); dt.Rows.Add(1, 2, 3); dt.Rows.Add(1, 2, 3); dt.Rows.Add(1, 2, 3); myGridView.DataSource = dt; myGridView.DataBind(); } protected void myGridView_RowCommand(object sender, GridViewCommandEventArgs e) { } } } I was thinking that when I click the command button, it would fire the mygridview_rowcommand() but instead it threw an error as follows: Invalid postback or callback argument. Event validation is enabled using in configuration or <%@ Page EnableEventValidation="true" % in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation. Can any one let me know on where I am going wrong?

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  • is there any way we can disable on mouse over event on certain columns of an data grid

    - by prince23
    hi, here wat i am trying to do is that on mouse over of first column i need to hit mouse MouseEnter event and show the pop up which i have kept there rest all other column i dnt need to to show the pop up so i am having this fuction there MouseLeave="Row_MouseLeave" <sdk:DataGrid MinHeight="100" x:Name="dgCounty" AutoGenerateColumns="False" VerticalAlignment="Top" Grid.Row="1" IsReadOnly="True" Margin="5,5,5,0" RowDetailsVisibilityChanged="dgCounty_RowDetailsVisibilityChanged" SelectionMode="Extended" RowDetailsVisibilityMode="VisibleWhenSelected" MouseEnter="dgCounty_MouseEnter" MouseLeave="dgCounty_MouseLeave" SelectionChanged="dgCounty_SelectionChanged" LoadingRow="dgCounty_LoadingRow1" UnloadingRow="dgCounty_UnloadingRow"> <sdk:DataGrid.Columns> <sdk:DataGridTemplateColumn> <sdk:DataGridTemplateColumn.CellTemplate> <DataTemplate> <Button x:Name="myButton" Width="24" Height="24" Click="Details_Click"> <Image x:Name="img" Source="Images/detail.JPG" Stretch="None"/> </Button> </DataTemplate> </sdk:DataGridTemplateColumn.CellTemplate> </sdk:DataGridTemplateColumn> <sdk:DataGridTemplateColumn Header="ID"> <sdk:DataGridTemplateColumn.CellTemplate> <DataTemplate > <sdk:Label Content="{Binding EmployeeID}" /> </DataTemplate> </sdk:DataGridTemplateColumn.CellTemplate> </sdk:DataGridTemplateColumn> <sdk:DataGridTemplateColumn Header="Name"> <sdk:DataGridTemplateColumn.CellTemplate> <DataTemplate > <sdk:Label Content="{Binding EmployeeFName}" MouseLeave="Row_MouseLeave" /> </DataTemplate> </sdk:DataGridTemplateColumn.CellTemplate> </sdk:DataGridTemplateColumn> <sdk:DataGridTemplateColumn Header="MailID"> <sdk:DataGridTemplateColumn.CellTemplate> <DataTemplate > <sdk:Label Content="{Binding EmployeeMailID}" MouseLeave="Row_MouseLeave" /> </DataTemplate> </sdk:DataGridTemplateColumn.CellTemplate> </sdk:DataGridTemplateColumn> </sdk:DataGrid.Columns> </sdk:DataGrid> in code behind void Row_MouseLeave(object sender, MouseEventArgs e) { Show.Visibility = Visibility.Collapsed; PoPGrid.Visibility = Visibility.Collapsed; } void Row_MouseEnter(object sender, MouseEventArgs e) { } the pop up her is like the ajax modal pop up wat we do in asp.net i am able to show data in pop up now the main issue is i need to show pop up only on the 2 column. rest all other column i need to hide the pop up when i move mouse over on that column. i am trying this concept it is not working is there any way i can achive it as i said only need to show pop up on mouse over of the 2 column thanks in advance prince

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  • What am I not getting about this abstract class implementation?

    - by Schnapple
    PREFACE: I'm relatively inexperienced in C++ so this very well could be a Day 1 n00b question. I'm working on something whose long term goal is to be portable across multiple operating systems. I have the following files: Utilities.h #include <string> class Utilities { public: Utilities() { }; virtual ~Utilities() { }; virtual std::string ParseString(std::string const& RawString) = 0; }; UtilitiesWin.h (for the Windows class/implementation) #include <string> #include "Utilities.h" class UtilitiesWin : public Utilities { public: UtilitiesWin() { }; virtual ~UtilitiesWin() { }; virtual std::string ParseString(std::string const& RawString); }; UtilitiesWin.cpp #include <string> #include "UtilitiesWin.h" std::string UtilitiesWin::ParseString(std::string const& RawString) { // Magic happens here! // I'll put in a line of code to make it seem valid return ""; } So then elsewhere in my code I have this #include <string> #include "Utilities.h" void SomeProgram::SomeMethod() { Utilities *u = new Utilities(); StringData = u->ParseString(StringData); // StringData defined elsewhere } The compiler (Visual Studio 2008) is dying on the instance declaration c:\somepath\somecode.cpp(3) : error C2259: 'Utilities' : cannot instantiate abstract class due to following members: 'std::string Utilities::ParseString(const std::string &)' : is abstract c:\somepath\utilities.h(9) : see declaration of 'Utilities::ParseString' So in this case what I'm wanting to do is use the abstract class (Utilities) like an interface and have it know to go to the implemented version (UtilitiesWin). Obviously I'm doing something wrong but I'm not sure what. It occurs to me as I'm writing this that there's probably a crucial connection between the UtilitiesWin implementation of the Utilities abstract class that I've missed, but I'm not sure where. I mean, the following works #include <string> #include "UtilitiesWin.h" void SomeProgram::SomeMethod() { Utilities *u = new UtilitiesWin(); StringData = u->ParseString(StringData); // StringData defined elsewhere } but it means I'd have to conditionally go through the different versions later (i.e., UtilitiesMac(), UtilitiesLinux(), etc.) What have I missed here?

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  • C# Detect Localhost Port Usage

    - by ThaKidd
    In advance, thank you for your advice. I am currently working on a program which uses Putty to create a SSH connection with a server that uses local port forwarding to enable a client, running my software, to access the service behind the SSH server via localhost. IE: client:20100 - Internet - Remote SSH server exposed via router/firewall - Local Intranet - Intranet Web POP3 Server:110. Cmd Line: "putty -ssh -2 -P 22 -C -L 20100:intranteIP:110 -pw sshpassword sshusername@sshserver" Client would use putty to create a SSH connection with the SSH server specifying in the connection string that it would like to tie port 110 of the Intranet POP3 Server to port 20100 on the client system. Therefore the client would be able to open up a mail client to localhost:20100 and interact with the Internal POP3 server over the SSH tunnel. The above is a general description. I already know what I am trying to do will work without a problem so am not looking for debate on the above. The question is this...How can I ensure the local port (I cannot use dynamic ports, so it must be static) on localhost is not being used or listened to by any other application? I am currently executing this code in my C# app: private bool checkPort(int port) { try { //Create a socket on the current IPv4 address Socket TestSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); // Create an IP end point IPEndPoint localIP = new IPEndPoint(IPAddress.Parse("127.0.0.1"), port); // Bind that port TestSocket.Bind(localIP); // Cleanup TestSocket.Close(); return false; } catch (Exception e) { // Exception occurred. Port is already bound. return true; } } I am currently calling this function starting with a specific port in a for loop to get the 'false' return at the first available port. The first port I try is actually being listened to by uTorrent. The above code does not catch this and my connection fails. What is the best method to ensure a port is truly free? I do understand some other program may grab the port during/after I have tested it. I just need to find something that will ensure it is not currently in use AT ALL when the test is executed. If there is a way to truly reserve the localhost port during the test, I would love to hear about it.

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  • What is a good platform for building a game framework targetting both web and native languages?

    - by fuzzyTew
    I would like to develop (or find, if one is already in development) a framework with support for accelerated graphics and sound built on a system flexible enough to compile to the following: native ppc/x86/x86_64/arm binaries or a language which compiles to them javascript actionscript bytecode or a language which compiles to it (actionscript 3, haxe) optionally java I imagine, for example, creating an API where I can open windows and make OpenGL-like calls and the framework maps this in a relatively efficient manner to either WebGL with a canvas object, 3d graphics in Flash, OpenGL ES 2 with EGL, or desktop OpenGL in an X11, Windows, or Cocoa window. I have so far looked into these avenues: Building the game library in haXe Pros: Targets exist for php, javascript, actionscript bytecode, c++ High level, object oriented language Cons: No support for finally{} blocks or destructors, making resource cleanup difficult C++ target does not allow room for producing highly optimized libraries -- the foreign function interface requires all primitive types be boxed in a wrapper object, as if writing bindings for a scripting language; these feel unideal for real-time graphics and audio, especially exporting low-level functions. Doesn't seem quite yet mature Using the C preprocessor to create a translator, writing programs entirely with macros Pros: CPP is widespread and simple to use Cons: This is an arduous task and probably the wrong tool for the job CPP implementations differ widely in support for features (e.g. xcode cpp has no variadic macros despite claiming C99 compliance) There is little-to-no room for optimization in this route Using llvm's support for multiple backends to target c/c++ to web languages Pros: Can code in c/c++ LLVM is a very mature highly optimizing compiler performing e.g. global inlining Targets exist for actionscript (alchemy) and javascript (emscripten) Cons: Actionscript target is closed source, unmaintained, and buggy. Javascript targets do not use features of HTML5 for appropriate optimization (e.g. linear memory with typed arrays) and are immature An LLVM target must convert from low-level bytecode, so high-level constructs are lost and bloated unreadable code is created from translating individual instructions, which may be more difficult for an unprepared JIT to optimize. "jump" instructions cause problems for languages with no "goto" statements. Using libclang to write a translator from C/C++ to web languages Pros: A beautiful parsing library providing easy access to the code structure Can code in C/C++ Has sponsored developer effort from Apple Cons: Incomplete; current feature set targets IDEs. Basic operators are unexposed and must be manually parsed from the returned AST element to be identified. Translating code prior to compilation may forgo optimizations assumed in c/c++ such as inlining. Creating new code generators for clang to translate into web languages Pros: Can code in C/C++ as libclang Cons: There is no API; code structure is unstable A much larger job than using libclang; the innards of clang are complex Building the game library in Common Lisp Pros: Flexible, ancient, well-developed language Extensive introspection should ease writing translators Translators exist for at least javascript Cons: Unfamiliar language No standardized library functions, widely varying implementations Which of these avenues should I pursue? Do you know of any others, or any systems that might be useful? Does a general project like this exist somewhere already? Thank you for any input.

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  • Constructor or Explicit cast

    - by Felan
    In working with Linq to Sql I create a seperate class to ferry data to a web page. To simplify creating these ferry objects I either use a specialized constructor or an explicit conversion operator. I have two questions. First which approach is better from a readibility perspective? Second while the clr code that is generated appeared to be the same to me, are there situations where one would be treated different than the other by the compiler (in lambda's or such). Example code (DatabaseFoo uses specialized constructor and BusinessFoo uses explicit operator): public class DatabaseFoo { private static int idCounter; // just to help with generating data public int Id { get; set; } public string Name { get; set; } public DatabaseFoo() { Id = idCounter++; Name = string.Format("Test{0}", Id); } public DatabaseFoo(BusinessFoo foo) { this.Id = foo.Id; this.Name = foo.Name; } } public class BusinessFoo { public int Id { get; set; } public string Name { get; set; } public static explicit operator BusinessFoo(DatabaseFoo foo) { return FromDatabaseFoo(foo); } public static BusinessFoo FromDatabaseFoo(DatabaseFoo foo) { return new BusinessFoo {Id = foo.Id, Name = foo.Name}; } } public class Program { static void Main(string[] args) { Console.WriteLine("Creating the initial list of DatabaseFoo"); IEnumerable<DatabaseFoo> dafoos = new List<DatabaseFoo>() { new DatabaseFoo(), new DatabaseFoo(), new DatabaseFoo(), new DatabaseFoo(), new DatabaseFoo(), new DatabaseFoo()}; foreach(DatabaseFoo dafoo in dafoos) Console.WriteLine(string.Format("{0}\t{1}", dafoo.Id, dafoo.Name)); Console.WriteLine("Casting the list of DatabaseFoo to a list of BusinessFoo"); IEnumerable<BusinessFoo> bufoos = from x in dafoos select (BusinessFoo) x; foreach (BusinessFoo bufoo in bufoos) Console.WriteLine(string.Format("{0}\t{1}", bufoo.Id, bufoo.Name)); Console.WriteLine("Creating a new list of DatabaseFoo by calling the constructor taking BusinessFoo"); IEnumerable<DatabaseFoo> fufoos = from x in bufoos select new DatabaseFoo(x); foreach(DatabaseFoo fufoo in fufoos) Console.WriteLine(string.Format("{0}\t{1}", fufoo.Id, fufoo.Name)); } }

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  • JPanel components paint-time problem

    - by Tom Brito
    I'm having a problem that when my frame is shown (after a login dialog) the buttons are not on correct position, then in some miliseconds they go to the right position (the center of the panel with border layout). When I make a SSCCE, it works correct, but when I run my whole code I have this fast-miliseconds delay to the buttons to go to the correct place. Unfortunately, I can't post the whole code, but the method that shows the frame is: public void login(JComponent userView) { centerPanel.removeAll(); centerPanel.add(userView); centerPanel.revalidate(); centerPanel.repaint(); frame.setVisible(true); } What would cause this delay to the panel layout? (I'm running everything in the EDT) -- update In my machine, this SSCCE shows the layout problem in 2 of 10 times I run it: import java.awt.BorderLayout; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.SwingUtilities; public class TEST { public static void main(String[] args) throws Exception { SwingUtilities.invokeAndWait(new Runnable() { @Override public void run() { System.out.println("Debug test..."); JPanel btnPnl = new JPanel(); btnPnl.add(new JButton("TEST")); JFrame f = new JFrame("TEST"); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.getContentPane().setLayout(new BorderLayout()); f.getContentPane().add(btnPnl); f.pack(); f.setSize(800, 600); f.setVisible(true); System.out.println("End debug test!"); } }); } } The button first appers in the up-left, and then it goes to the center. Please, note that I'm understand, not just correct. Is it a java bug? --update OK, so the SSCCE don't show the problem with you that tried till now. Maybe it's my computer performance problem. But this don't answer the question, I still think Java Swing is creating new threads for make the layout behind the scenes.

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  • On Mac, two jpg's whose color should match do not

    - by Tim
    So I'm designing a myspace page and I have two images, one is a repeating bg image, and another is an image which loads on a layer above it, which acts as a header/masthead. For some reason, on Macs only, and only in the browser (tested in safari and ff), the masthead renders slightly darker than the repeating bg image, creating this color inconsistency. The block that extends up behind the album artwork is a solid box made with css which blocks some of myspace's standard content. It actually renders as the proper color, blending in well with the bottom portion of this image, which is the repeating part of the background, but becomes noticeable as it extends up, over the masthead, which is darker than it should be. Both images where created in GIMP and saved as jpg's using, as far as i can tell, the same settings. Here's the pic of what is going on: Screenshot - Click Me!!! Here is the code which controls this part of the design. <div class="masthead"><span></span></div> .masthead {width: 1600px; height: 1940px; background-image:url(http://www.sourtricks.com/myspace/bdww/myspace_bg09.jpg); position: absolute; margin-left: -800px; left: 50%; top: 0px; z-index: -1; overflow-x: hidden;} body.bodyContent{ margin: 0 !important; padding: 0 !important; background-color: 000000 !important; font-size: 1px; background-image: url(http://www.sourtricks.com/myspace/bdww/bg_repeat05.jpg); background-position: center bottom; _background-position: right bottom; background-attachment: scroll; background-repeat: repeat-y; z-index: -2; overflow-x: hidden; font-family: arial, sans-serif !important; } Any help would be much, much, much appreciated. Thanks for your time, Tim

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  • How to update the session values on partial post back and how to make Javascript use the new values

    - by Mano
    The problem I am facing is the I am passing values to javascript to draw a graph using session values in the code behind. When page loads it take the value from the session and creates the graph, when I do partial post back using a Update Panel and Timer, I call the method to add values to the session and it does it. public void messsagePercentStats(object sender, EventArgs args) { ... if (value >= lowtarg && value < Toptarg) { vProgressColor = "'#eaa600'"; } else if (value >= Toptarg) { vProgressColor = "'#86cf21'"; } Session.Add("vProgressColor", vProgressColor); Session.Add("vProgressPercentage", "["+value+"],["+remaining+"]"); } } I use the update panel to call the above method <asp:ScriptManager ID="smCharts" runat="server" /> <asp:UpdatePanel runat="server" ID="Holder" OnLoad="messsagePercentStats" UpdateMode="Conditional"> <ContentTemplate> <asp:Timer ID="Timer1" runat="server" Interval="5000" OnTick="Timer_Tick" /> and the timer_tick method is executed every 5 seconds protected void Timer_Tick(object sender, EventArgs args) { ScriptManager.RegisterStartupScript(this, this.GetType(), "key", "r.init();", true); ResponseMetric rm = new ResponseMetric(); Holder.Update(); } I use ScriptManager.RegisterStartupScript(this, this.GetType(), "key", "r.init();", true); to call the r.init() Java script method to draw the graph on post back and it works fine. Java Script: var r = { init : function(){ r = Raphael("pie"), data2 = [<%= Session["vProgressPercentage"] %>]; axisx = ["10%", "20%"]; r.g.txtattr.font = "12px 'Fontin Sans', Fontin-Sans, sans-serif"; r.g.barchart(80, 25, 100, 320, data2, { stacked: true, colors: [<%= Session["vProgressColor"] %>,'#fff'] }); axis2 = r.g.axis(94, 325, 280, 0, 100, 10, 1); } } window.onload = function () { r.init(); }; This Java Script is not getting the new value from the session, it uses the old value when the page was loaded. How can I change the code to make sure the JS uses the latest session value.

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  • Seeking STL-aware c++filt

    - by Don Wakefield
    In my development environment, I'm compiling a code base using GNU C++ 3.4.6. Code is under development, and unfortunately crashes now and then. It's nice to be able to run the traceback through a demangler, and I use c++filt 3.4. The problem comes when functions have a number of STL parameters. Consider My_callback::operator()( Status&, std::set<std::string> const&, std::vector<My_parameter*> const&, My_attribute_set const&, std::vector<My_parameter_base*> const&, std::vector<My_parameter> const&, std::set<std::string> const& ) { // ... } When this function is in the traceback, the mangled output on my platform is: (_ZN30My_callbackclER11StatusRKSt3setISsSt4lessISsESaISsEERKSt6vectorIP13My_parameterSaISB_EERK17My_attribute_setRKS9_IP18My_parameter_baseSaISK_EERKS9_ISA_SaISA_EES8_+0x76a) [0x13ffdaa] c++filt kindly demangles it to (My_callback::operator()(Status&, std::set<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > const&, std::vector<My_parameter*, std::allocator<My_parameter*> > const&, My_attribute_set const&, std::vector<My_parameter_base*, std::allocator<My_parameter_base*> > const&, std::vector<My_parameter, std::allocator<My_parameter> > const&, std::set<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > const&)+0x76a) [0x13ffdaa] This is the same problem as compiler errors encountered when using templates. However, the STL is a fairly regular and recognizable package of templates. So what I'm hoping is that someone out there has created an enhanced version of c++filt which would dump something closer to the original function signature. Any hints?

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  • Why no switch on pointers?

    - by meeselet
    For instance: #include <stdio.h> void why_cant_we_switch_him(void *ptr) { switch (ptr) { case NULL: printf("NULL!\n"); break; default: printf("%p!\n", ptr); break; } } int main(void) { void *foo = "toast"; why_cant_we_switch_him(foo); return 0; } gcc test.c -o test test.c: In function 'why_cant_we_switch_him': test.c:5: error: switch quantity not an integer test.c:6: error: pointers are not permitted as case values Just curious. Is this a technical limitation? EDIT People seem to think there is only one constant pointer expression. Is that is really true, though? For instance, here is a common paradigm in Objective-C (it is really only C aside from NSString, id and nil, which are merely a pointers, so it is still relevant — I just wanted to point out that there is, in fact, a common use for it, despite this being only a technical question): #include <stdio.h> #include <Foundation/Foundation.h> static NSString * const kMyConstantObject = @"Foo"; void why_cant_we_switch_him(id ptr) { switch (ptr) { case kMyConstantObject: // (Note that we are comparing pointers, not string values.) printf("We found him!\n"); break; case nil: printf("He appears to be nil (or NULL, whichever you prefer).\n"); break; default: printf("%p!\n", ptr); break; } } int main(void) { NSString *foo = @"toast"; why_cant_we_switch_him(foo); foo = kMyConstantObject; why_cant_we_switch_him(foo); return 0; } gcc test.c -o test -framework Foundation test.c: In function 'why_cant_we_switch_him': test.c:5: error: switch quantity not an integer test.c:6: error: pointers are not permitted as case values It appears that the reason is that switch only allows integral values (as the compiler warning said). So I suppose a better question would be to ask why this is the case? (though it is probably too late now.)

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  • How the simples GUI countdown is supposed to work?

    - by Roman
    I am trying to write the simples GUI countdown. I found in Internet some code but it is already too fancy for me. I am trying to keep it as simple as possible. So, I just want to have a window saying "You have 10 second left". The number of second should decrease every second from 10 to 0. I wrote a code. And I think I am close to the working solution. But I still missing something. Could you pleas help me to find out what is wrong? Here is my code: import javax.swing.*; public class Countdown { static JLabel label; // Method which defines the appearance of the window. private static void showGUI() { JFrame frame = new JFrame("Simple Countdown"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JLabel label = new JLabel("Some Text"); frame.add(label); frame.pack(); frame.setVisible(true); } // Define a new thread in which the countdown is counting down. static Thread counter = new Thread() { public void run() { for (int i=10; i>0; i=i-1) { updateGUI(i,label); try {Thread.sleep(1000);} catch(InterruptedException e) {}; } } }; // A method which updates GUI (sets a new value of JLabel). private static void updateGUI(final int i, final JLabel label) { SwingUtilities.invokeLater(new Runnable(i,label) { public Runnable(int i, JLabel label) { this.i = i; this.label = label; } public void run() { label.setText("You have " + i + " seconds."); } }); } // The main method (entry point). public static void main(String[] args) { javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { showGUI(); //counter.start(); } }); //counter.start(); } } And I have several concrete question about this code: Where should I place the counter.start();? (In my code I put it on 2 places. Which one is correct?) Why compiler complains about the constructor for Runnable? It says that I have an invalid method declaration and I need to specify the returned type. ADDED: I made the suggested corrections. And then I execute the code and get: Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at Worker.run(Worker.java:12) In the Worker.java in the line 12 I have: label.setText("You have " + i + " seconds.");.

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  • Is do-notation specific to "base:GHC.Base.Monad"?

    - by yairchu
    The idea that the standard Monad class is flawed and that it should actually extend Functor or Pointed is floating around. I'm not necessarily claiming that it is the right thing to do, but suppose that one was trying to do it: import Prelude hiding (Monad(..)) class Functor m => Monad m where return :: a -> m a join :: m (m a) -> m a join = (>>= id) (>>=) :: m a -> (a -> m b) -> m b a >>= t = join (fmap t a) (>>) :: m a -> m b -> m b a >> b = a >>= const b So far so good, but then when trying to use do-notation: whileM :: Monad m => m Bool -> m () whileM iteration = do done <- iteration if done then return () else whileM iteration The compiler complains: Could not deduce (base:GHC.Base.Monad m) from the context (Monad m) Question: Does do-notation work only for base:GHC.Base.Monad? Is there a way to make it work with an alternative Monad class? Extra context: What I really want to do is replace base:Control.Arrow.Arrow with a "generalized" Arrow class: {-# LANGUAGE TypeFamilies #-} class Category a => Arrow a where type Pair a :: * -> * -> * arr :: (b -> c) -> a b c first :: a b c -> a (Pair a b d) (Pair a c d) second :: a b c -> a (Pair a d b) (Pair a d c) (***) :: a b c -> a b' c' -> a (Pair a b b') (Pair a c c') (&&&) :: a b c -> a b c' -> a b (Pair a c c') And then use the Arrow's proc-notation with my Arrow class, but that fails like in the example above of do-notation and Monad. I'll use mostly Either as my pair type constructor and not the (,) type constructor as with the current Arrow class. This might allow to make the code of my toy RTS game (cabal install DefendTheKind) much prettier.

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