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• Service reference addition issue in visual studio 2010

  - by user293072

  I am currently working on an application that allows reverse geocoding using silverlight + bing maps. The thing is that I want to add a reference to the reverse geocoding service provided in msdn ( http://msdn.microsoft.com/en-us/library/cc879136.aspx) i.e. http:// dev.virtualearth.net/webservices/v1/geocodeservice/geocodeservice.svc?wsdl, but when I try to get a reference in vs2010, I get the following error: The document at the url http:// dev.virtualearth.net/webservices/v1/metadata/geocodeservice/geocodeservice.wsdl was not recognized as a known document type. The error message from each known type may help you fix the problem: Report from 'XML Schema' is ''', hexadecimal value 0x1F, is an invalid character. Line 1, position 1.'. Report from 'DISCO Document' is ''', hexadecimal value 0x1F, is an invalid character. Line 1, position 1.'. Report from 'WSDL Document' is 'There is an error in XML document (1, 1).'. '', hexadecimal value 0x1F, is an invalid character. Line 1, position 1. Metadata contains a reference that cannot be resolved: 'http://dev.virtualearth.net/webservices/v1/geocodeservice/geocodeservice.svc?wsdl'. Content Type application/soap+xml; charset=utf-8 was not supported by service http: //dev.virtualearth.net/webservices/v1/geocodeservice/geocodeservice.svc?wsdl. The client and service bindings may be mismatched. The remote server returned an error: (415) Unsupported Media Type. If the service is defined in the current solution, try building the solution and adding the service reference again. It is good to mention that I can access the service URL from the browser (with a no style information warning). I am aware that there are other reverse geolocoding services out there, but I am somewhat forced by certain circumstances to use only Microsoft-related components/services. Please help :)

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• OpenCV: Shift/Align face image relative to reference Image (Image Registration)

  - by Abhischek

  I am new to OpenCV2 and working on a project in emotion recognition and would like to align a facial image in relation to a reference facial image. I would like to get the image translation working before moving to rotation. Current idea is to run a search within a limited range on both x and y coordinates and use the sum of squared differences as error metric to select the optimal x/y parameters to align the image. I'm using the OpenCV face_cascade function to detect the face images, all images are resized to a fixed (128x128). Question: Which parameters of the Mat image do I need to modify to shift the image in a positive/negative direction on both x and y axis? I believe setImageROI is no longer supported by Mat datatypes? I have the ROIs for both faces available however I am unsure how to use them. void alignImage(vector<Rect> faceROIstore, vector<Mat> faceIMGstore) { Mat refimg = faceIMGstore[1]; //reference image Mat dispimg = faceIMGstore[52]; // "displaced" version of reference image //Rect refROI = faceROIstore[1]; //Bounding box for face in reference image //Rect dispROI = faceROIstore[52]; //Bounding box for face in displaced image Mat aligned; matchTemplate(dispimg, refimg, aligned, CV_TM_SQDIFF_NORMED); imshow("Aligned image", aligned); } The idea for this approach is based on Image Alignment Tutorial by Richard Szeliski Working on Windows with OpenCV 2.4. Any suggestions are much appreciated.

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• Reference-type conversion operators: asking for trouble?

  - by Ben

  When I compile the following code using g++ class A {}; void foo(A&) {} int main() { foo(A()); return 0; } I get the following error messages: > g++ test.cpp -o test test.cpp: In function ‘int main()’: test.cpp:10: error: invalid initialization of non-const reference of type ‘A&’ from a temporary of type ‘A’ test.cpp:6: error: in passing argument 1 of ‘void foo(A&)’ After some reflection, these errors make plenty of sense to me. A() is just a temporary value, not an assignable location on the stack, so it wouldn't seem to have an address. If it doesn't have an address, then I can't hold a reference to it. Okay, fine. But wait! If I add the following conversion operator to the class A class A { public: operator A&() { return *this; } }; then all is well! My question is whether this even remotely safe. What exactly does this point to when A() is constructed as a temporary value? I am given some confidence by the fact that void foo(const A&) {} can accept temporary values according to g++ and all other compilers I've used. The const keyword can always be cast away, so it would surprise me if there were any actual semantic differences between a const A& parameter and an A& parameter. So I guess that's another way of asking my question: why is a const reference to a temporary value considered safe by the compiler whereas a non-const reference is not?

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• VS2010 express beta2 - no add reference dialog, no open file/project dialogs

  - by David

  Just installed VS2010 express for Windows Phone last night. Install went smoothly. It creates a project, compiles, and deploys the app to the emulator. Here's the problem: When I try to "Add Reference" through the Project menu, I do not get the Add Reference dialog box. Same thing if I right click References in the solution explorer and click Add Reference. That's not all. "File...Open" and "File...Open Project" also fail to throw up an open file dialog box. When attempting any of these actions, the IDE quickly loses and regains focus. Even pressing a keyboard shortcut (Ctrl+O) causes the IDE to quickly lose and regain focus, but no open file dialog box appears. This is what I have tried, not particularly in this order: 1. Turned off UAC 2. Monitored file and registry access using Process Monitor during a File...Open operation. File activity showed mostly "SUCCESS" with a few "FAST IO DISALLOWED" and a few "INVALID DEVICE REQUEST" results. Registry activity showed mostly "SUCCESS" with some "NAME NOT FOUND" and a few "BUFFER OVERFLOW" results. 3. Created a new, clean Windows account to run the IDE from 4. Forced a test project to add a reference to "System.Xml.Linq" by editing the ".csproj" project file. Project failed to load in the IDE. I don't have these problems at all on 2 other Windows 7 computers with VS2010 C# express beta 2 installed. One machine is 32bit and the other 64bit, both Home Premium edition. My system: Windows 7 Home Premium, 64bit Other Visual Studio products installed: VS2008 C# express, VS2008 C++ express One other thing to note: Several months ago I installed the non-phone distribution of VS2010 C# express beta 2, and I had the same exact problems. Back then I chalked it up to being beta and went back to VS2008 C# express, where I do not have these issues.

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• Unable to change URL for .NET reference to dynamic web service

  - by Malvineous

  Hi all, I have a web reference added to a C# .NET project. The URL for the web reference needs to change depending on whether I'm building for a development, staging or production environment. I've set the web service to be dynamic, which supposedly means it takes the URL from my app.config file. When I perform a build it overwrites the app.config with the required file which contains the correct URL (different file for each of dev/staging/production.) I then go into the solution properties and make sure the Settings.settings file is updated with the app.config changes. However when I view the properties for the web service, it is still showing the old URL, despite it being dynamic, and supposed to be reading from my settings file (even after closing and reopening the project/solution.) The app.config and the settings file all have the new URL, but the web reference doesn't notice it has changed. If I do a build it ignores the URL in the settings file and tries to connect to the last URL manually typed into the web reference's properties. Typing a URL into these properties correctly updates the app.config and .settings files, so the link is definitely there. I'm a bit new to .NET but it seems to me the purpose of setting the service to be dynamic is so that you can change the URL elsewhere, but when I do this it just gets ignored! Am I doing something wrong?

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• Micrsoft Silverlight 3 cannot create service reference to localhost:port

  - by Monte

  Windows Server 2003 (IIS 6) Visual Studio 2008 .NET FrameWork 3.5 SP1 I am a .NET developer for a living and I have over 40 hours in the problem Project type = "Silverlight Navigation Application", "APS.NET Web Site" (when I tried it as "ASP.NET Web Application Project" I could not copy it to the production web site - well I could copy it but I could not make it run) Created a service.cs on the .Web side of the application. Created a reference to that service.cs on the Silverlight side. For a time all is good as I can reference the service as localhost:port (e.g. localhost:1374) in Visual Studio and debug both Silverlight side and service.cs To access the application in production mode (from IE) I update the service refrence and replace localhost:port with the IP address. The problem with the IP address is I cannot debug the service.cs so I have to change it back to localhost:port to debug. Now to the problem. After a period of time localhost:port just plain breaks. I get an error message no service at the other end Yes I know the port can change - that is not the problem - the port on the service side just plain breaks! For example from Visual Studio from the Silverlight side of the project right click "Service Reference", "Add Service Reverence". It finds 1 service in the application on a port. But when I click that service under "Services:" in the modal dialog box "Add Service Reference" I get an error: There was an error downloading 'http://localhost:1377/SehaleCSS.Web/Service.svc'. The request failed with the error message: -- Could not load file or assembly 'App_Web_tipnndfq, If I go back to the IP address the service is repsponding (with the right answer) The service just plain goes a while responding to localhost:port and then fails Even making NO change to service.cs it go a while then fails as a localhost:port It is not IIS environmental as I can go back to a prior saved version of the code and it works Something is happening that the .web side of the application is failing. It still works as an IP and it still exposes itself as a localhost:port but it fails to properly repsonde as a localhost:port.

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• Using custom FaultContract object causes 'Add Service Reference' to fail

  - by SpoBo

  Hey, I just noticed something particular. I have an internal stock service which is published through basicHttpBinding, and a customBinding (http+binary) for which metadata is enabled. I also included a mex endpoint for http. We use Visual Studio 2008 & VB.NET Just recently we noticed that we were unable to succesfully add a service reference to this service in our other projects. All that it would generate was the first custom exception we included through a FaultContract (actually, there was only 1 type). if I'd add a simple web reference it would work correctly as well. Also, the WcfClient.exe had no problems either in loading the services. Just VS.NET add service reference wouldn't work. In the service this exception inherits from Exception and is marked as serializable. That's all you're supposed to do, no? Anyway, this had me baffled. If I remove the FaultContract for this custom exception everything works fine. I can add a service reference, no problem. But is there a way I can still have my custom exceptions? Is this a known problem? Thx!

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• Accessing local variable doesn't improve performance

  - by NicMagnier

  The short version Why is this code: var index = (Math.floor(y / scale) * img.width + Math.floor(x / scale)) * 4; More performant than this one? var index = Math.floor(ref_index) * 4; The long version This week, the author of Impact js published an article about some rendering issue: http://www.phoboslab.org/log/2012/09/drawing-pixels-is-hard In the article there was the source of a function to scale an image by accessing pixels in the canvas. I wanted to suggest some traditional ways to optimize this kind of code so that the scaling would be shorter at loading time. But after testing it my result was most of the time worst that the original function. Guessing this was the JavaScript engine that was doing some smart optimization I tried to understand a bit more what was going on so I did a bunch of test. But my results are quite confusing and I would need some help to understand what's going on. I have a test page here: http://www.mx981.com/stuff/resize_bench/test.html jsPerf: http://jsperf.com/local-variable-due-to-the-scope-lookup To start the test, click the picture and the results will appear in the console. There are three different versions: The original code: for( var y = 0; y < heightScaled; y++ ) { for( var x = 0; x < widthScaled; x++ ) { var index = (Math.floor(y / scale) * img.width + Math.floor(x / scale)) * 4; var indexScaled = (y * widthScaled + x) * 4; scaledPixels.data[ indexScaled ] = origPixels.data[ index ]; scaledPixels.data[ indexScaled+1 ] = origPixels.data[ index+1 ]; scaledPixels.data[ indexScaled+2 ] = origPixels.data[ index+2 ]; scaledPixels.data[ indexScaled+3 ] = origPixels.data[ index+3 ]; } } jsPerf: http://jsperf.com/so-accessing-local-variable-doesn-t-improve-performance One of my attempt to optimize it: var ref_index = 0; var ref_indexScaled = 0 var ref_step = 1 / scale; for( var y = 0; y < heightScaled; y++ ) { for( var x = 0; x < widthScaled; x++ ) { var index = Math.floor(ref_index) * 4; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index ]; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index+1 ]; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index+2 ]; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index+3 ]; ref_index+= ref_step; } } jsPerf: http://jsperf.com/so-accessing-local-variable-doesn-t-improve-performance The same optimized code but with recalculating the index variable each time (Hybrid) var ref_index = 0; var ref_indexScaled = 0 var ref_step = 1 / scale; for( var y = 0; y < heightScaled; y++ ) { for( var x = 0; x < widthScaled; x++ ) { var index = (Math.floor(y / scale) * img.width + Math.floor(x / scale)) * 4; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index ]; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index+1 ]; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index+2 ]; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index+3 ]; ref_index+= ref_step; } } jsPerf: http://jsperf.com/so-accessing-local-variable-doesn-t-improve-performance The only difference in the two last one is the calculation of the 'index' variable. And to my surprise the optimized version is slower in most browsers (except opera). Results of personal testing (not the jsPerf tests): Opera Original: 8668ms Optimized: 932ms Hybrid: 8696ms Chrome Original: 139ms Optimized: 145ms Hybrid: 136ms Safari Original: 433ms Optimized: 853ms Hybrid: 451ms Firefox Original: 343ms Optimized: 422ms Hybrid: 350ms After digging around, it seems an usual good practice is to access mainly local variable due to the scope lookup. Because The optimized version only call one local variable it should be faster that the Hybrid code which call multiple variable and object in addition to the various operation involved. So why the "optimized" version is slower? I thought that it might be because some JavaScript engine don't optimize the Optimized version because it is not hot enough but after using --trace-opt in chrome, it seems all version are properly compiled by V8. At this point I am a bit clueless and wonder if somebody would know what is going on? I did also some more test cases in this page: http://www.mx981.com/stuff/resize_bench/index.html

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• How to change Fluent NHibernate reference column name on a HasMany relationship using IHasManyConven

  - by snicker

  Currently I'm using Fluent NHibernate to generate my database schema, but I want the entities in a HasMany relationship to point to a different column for the reference. IE, this is what NHibernate will generate in the creation DDL: alter table `Pony` add index (Stable_ID), add constraint Ponies_Stable foreign key (Stable_Id) references `Stable` (Id); This is what I want to have: alter table `Pony` add index (Stable_ID), add constraint Ponies_Stable foreign key (Stable_Id) references `Stable` (EntityId); Where Stable.ID would be the primary key and Stable.EntityId is just another column that I set. I have a class already that looks like this: public class ForeignKeyReferenceConvention : IHasManyConvention { public void Apply(IOneToManyCollectionInstance instance) { instance.Cascade.All(); //What goes here so that I can change the reference column? } } What do I have to do to get the reference column to change?

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• Visual Studio 2010: adding a service reference to a 2008 generated wsdl

  - by Snake

  Doesn't produce a app.config . In my team there is a guy who has Visual Studio 2008, he created a webservice. Then there is me, adding this webservice to a console project. Adding the service reference goes without problems but no valid app.config is generated. It's just empty <configuration> </configuration> When I disable 'reuse types' in my service reference it works but then I get an ambiguous error. Is this a bug? I found http://stackoverflow.com/questions/2159107/visual-studio-does-not-generate-app-config-content-when-add-service-reference this one, but there is no solution there, so I thought I bump the problem up again. Thanks

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• About function scopes in javascript

  - by Shawn

  Look at the code below. I want to alert the value of i at the moment that specific listener was added. Is other words, clicking each marker should alert a different value. Where can I store the value of i in a way that it won't change and be accessible inside the scope of that function? Here is problematic code: (it is difficult to test because you need a key from Google) <html> <head> <title>a</title> <script type="text/javascript"> function init() { map = new GMap2(document.getElementById("map_canvas")); // http://code.google.com/intl/es/apis/maps/documentation/reference.html#GMap2 map.setCenter(new GLatLng(0, 0), 1); // http://code.google.com/intl/es/apis/maps/documentation/reference.html#GMap2.setCenter for(var i = 0; i < 10; i++) { var marker = new GMarker(point); // http://code.google.com/intl/es/apis/maps/documentation/reference.html#GMarker map.addOverlay(marker); // http://code.google.com/intl/es/apis/maps/documentation/reference.html#GMap2.addOverlay GEvent.addListener(marker, "click", function() // http://code.google.com/intl/es/apis/maps/documentation/reference.html#GEvent.addListener { alert(i); // Problem: I want the value of i at the moment when the listener is added. }); } } window.onload = init; </script> </head> <body id="map_canvas"> </body> </html> Thanks!

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• Drupal - Grabbing and Looping NID of CCK Nodereference field

  - by GaxZE

  Hello, cant seem to work out how i grab multiple nids of a node reference field. $node-field_name[0]['nid'] picks up the node id of the cck node reference field. however when that cck node reference field has more than one value i get stuck! my php is abit sketchy atm so working with arrays and loops is being quite difficult! here is my code: field_industry as $item) { ? "

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• Change Casing in WCF Service Reference

  - by Eric J.

  I'm creating a service reference to a web service written in Java. The generated classes now follow the Java casing convention used in the web service, for example class names are camelCase rather than PascalCase. Is there a way to get the desired casing from the service reference? CLARIFICATION: With WSE based services, one could modify the generated Reference.cs to provide .NET standard casing and use XmlElementAttribute to map to the Java naming presented by the external web service, like this: [System.Xml.Serialization.XmlElementAttribute("resultType", Form=System.Xml.Schema.XmlSchemaForm.Unqualified)] [System.Runtime.Serialization.DataMember] public virtual MyResultType ResultType { ... } Not terribly maintenance-friendly without writing custom code to either generate the proxy code or modify it after it's been generated. What I'm after is one or more options to present a WCF generated client proxy to calling applications using the .NET casing conventions, achieving the same as I did previously with WSE. Hopefully with less manual effort.

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• Does GC guarantee that cleared References are enqueued to ReferenceQueue in topological order?

  - by Dimitris Andreou

  Say there are two objects, A and B, and there is a pointer A.x --> B, and we create, say, WeakReferences to both A and B, with an associated ReferenceQueue. Assume that both A and B become unreachable. Intuitively B cannot be considered unreachable before A is. In such a case, do we somehow get a guarantee that the respective references will be enqueued in the intuitive (topological when there are no cycles) order in the ReferenceQueue? I.e. ref(A) before ref(B). I don't know - what if the GC marked a bunch of objects as unreachable, and then enqueued them in no particular order? I was reviewing Finalizer.java of guava, seeing this snippet: private void cleanUp(Reference<?> reference) throws ShutDown { ... if (reference == frqReference) { /* * The client no longer has a reference to the * FinalizableReferenceQueue. We can stop. */ throw new ShutDown(); } frqReference is a PhantomReference to the used ReferenceQueue, so if this is GC'ed, no Finalizable{Weak, Soft, Phantom}References can be alive, since they reference the queue. So they have to be GC'ed before the queue itself can be GC'ed - but still, do we get the guarantee that these references will be enqueued to the ReferenceQueue at the order they get "garbage collected" (as if they get GC'ed one by one)? The code implies that there is some kind of guarantee, otherwise unprocessed references could theoretically remain in the queue. Thanks

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• TFS Build Server Cannot find Assembly Reference

  - by Steve Syfuhs

  I looked at this post http://stackoverflow.com/questions/547468/assembly-references-wont-resolve-properly-on-our-build-server but it didn't help the issue. I am (extremely) new to TFS, and just installed 2010 on a VM. I imported a project and got everything working-ish. I went to create a new build through team explorer, and set it up to build on each check-in. It build's locally just fine, but when it's built on check-in it dies on a 3rd party assembly reference. The reference is not in the GAC, but part of the local references. There is only one 3rd party dll, and the projects only reference each other in the solution. I have a feeling I'm missing some important step with regards to TFS and references. Any ideas? EDIT: This a test installation...there is nothing else installed on this box, with the exception of SQL and IIS.

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• Django template call function

  - by cleg

  I'm passing to Django's template a function, which returns me some records. I want to call this function and iterate over it's result. {% for item in my_func(10) %} That doesn't work. I've tried to set fuction's return value to a variable and iterate over variable, but there seems to be no way to set variable in Django template. Is there any normal way to do it?

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• Out of Memory on Update or Delete of Service Reference

  - by Kelly

  I have a Service Reference for a WCF project that has just over a hundred endpoints in my ServiceHost web.config. Every time I attempt to update or delete the Service Reference, it fails with an out of memory exception. I am running Vista Ultimate SP2 64-bit with 8GB RAM. I can work around it by going outside the project and deleting the Service References folder, then coming back in and re-adding the Reference. Is this the only workaround that you know of? Thanks!

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• HASH reference error with HTTP::Message::decodable

  - by scarba05

  Hi, I'm getting an "Can't use an undefined value as a HASH reference" error trying to call HTTP::Message::decodable() using Perl 5.10 / libwww installed on Debian Lenny OS using the aptitude package manager. I'm really stuck so would appreciate some help please. Here's the error: Can't use an undefined value as a HASH reference at (eval 2) line 1. at test.pl line 4 main::__ANON__('Can\'t use an undefined value as a HASH reference at enter code here`(eval 2)...') called at (eval 2) line 1 HTTP::Message::__ANON__() called at test.pl line 6 Here's the code: use strict; use HTTP::Request::Common; use Carp; $SIG{ __DIE__ } = sub { Carp::confess( @_ ) }; print HTTP::Message::decodable();

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• MySQL - How To Avoid Repair With Keycache?

  - by dvancouver

  I have had some experience with optimizing the my.cnf file but my database has around 4 million records (MyISAM). I am trying to restore from a mysqldump but every time I do I eventually get the dreaded "Repair With Keycache", that may take days. Is there anyway to get past this and let it roll as "Repair By Sorting"? I have 2GB RAM, Dual Cores, lots of extra hard-drive space. Snip out of my.cnf: set-variable = max_connections=650 set-variable = key_buffer=256M set-variable = myisam_sort_buffer_size=64M set-variable = join_buffer=1M set-variable = record_buffer=1M set-variable = sort_buffer_size=2M set-variable = read_buffer_size=2M set-variable = query_cache_size=32M set-variable = table_cache=1024 set-variable = thread_cache_size=256 set-variable = wait_timeout=7200 set-variable = connect_timeout=10 set-variable = max_allowed_packet=16M set-variable = max_connect_errors=10 set-variable = thread_concurrency=8

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• WCF Service Library Reference in a Web Form (asp.net)

  - by Abu Hamzah

  i am not sure if this is the correct way of doing but i read that you not suppose to have a WCF Service Library reference in your web form project rather you add endpoints to your web.config, is that true? here is what i have done: 1) create a WCF service library project 2) create a simple service called "MyService.svc" WebForm: 1) Create a web project 2) create a WCF Service and in it i have this code <%@ ServiceHost Language="C#" Service="WCFJQuery.ContactBLL.Implementation.ContactUs" Factory="System.ServiceModel.Activation.WebScriptServiceHostFactory" %> 3) right click on the web proejct and "Add Reference" and add teh MyService.dll reference from WCF service library project. is this something how you suppose to do?

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• Web service reference location?

  - by Damien Dennehy

  I have a Visual Studio 2008 solution that's currently consisting of three projects: A DataFactory project for Business Logic/Data Access. A Web project consisting of the actual user interface, pages, controls, etc. A Web.Core project consisting of utility classes, etc. The application requires consuming a web service. Normally I'd add the service reference to the Web project, but I'm not sure if this is best practice or not. The following options are open to me: Add the reference to the Web project. Add the reference to the Web.Core project, and create a wrapper method that Web will call to consume the web service. Add a new project called Web.Services, and copy step 2. This project is expected to increase in size so I'm open to any suggestions.

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• Adding Service Reference to a WCF Service in Silverlight project defaulting to XmlSerialization for

  - by Shravan

  Hi, I am adding a WCF Service Reference in a Silverlight project, it is generating code with XmlSerialization attributes for DataMembers than SOAP Serialization. But, if the same WCF service reference is added in an ASP.Net project, is generating code with SOAP Serialization attribtues. Can anybody let me know what could be the cause for it, and how can I force reference to generate SOAP Serialization? XmlSerialization - [System.CodeDom.Compiler.GeneratedCodeAttribute("System.Xml", "4.0.30319.1")] SOAP Serialization - [System.CodeDom.Compiler.GeneratedCodeAttribute("System.Runtime.Serialization", "4.0.0.0")] These are the attributes in the code generated for types, which I am looking into when saying it is using XmlSerialization/SOAP Serialization

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• Returning references while using shared_ptrs

  - by Goose Bumper

  Suppose I have a rather large class Matrix, and I've overloaded operator== to check for equality like so: bool operator==(Matrix &a, Matrix &b); Of course I'm passing the Matrix objects by reference because they are so large. Now i have a method Matrix::inverse() that returns a new Matrix object. Now I want to use the inverse directly in a comparison, like so: if (a.inverse()==b) { ... }` The problem is, this means the inverse method needs to return a reference to a Matrix object. Two questions: Since I'm just using that reference in this once comparison, is this a memory leak? What happens if the object-to-be-returned in the inverse() method belongs to a boost::shared_ptr? As soon as the method exits, the shared_ptr is destroyed and the object is no longer valid. Is there a way to return a reference to an object that belongs to a shared_ptr?

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• Reference to a pointer question

  - by Yogesh Arora

  Please refer to the code below. In this code i am storing the const char* returned by test.c_str() into a reference. My question is Will the data be correctly refering to the contents of test. I am thinking that ptr returned by test.c_str() will be a temporary and if i bound it to a reference that reference will not be valid. Is my thinking correct class RefPtrTest { std::string test; StoringClass storingClass; public: RefPtrTest(): test("hello"), storingClass(test.c_str()) { } } where StoringClass is class StoringClass { const char*& data; public: StoringClass (const char*& input): data(input) { } }

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• C++0x rvalue references and temporaries

  - by Doug

  (I asked a variation of this question on comp.std.c++ but didn't get an answer.) Why does the call to f(arg) in this code call the const ref overload of f? void f(const std::string &); //less efficient void f(std::string &&); //more efficient void g(const char * arg) { f(arg); } My intuition says that the f(string &&) overload should be chosen, because arg needs to be converted to a temporary no matter what, and the temporary matches the rvalue reference better than the lvalue reference. This is not what happens in GCC and MSVC. In at least G++ and MSVC, any lvalue does not bind to an rvalue reference argument, even if there is an intermediate temporary created. Indeed, if the const ref overload isn't present, the compilers diagnose an error. However, writing f(arg + 0) or f(std::string(arg)) does choose the rvalue reference overload as you would expect. From my reading of the C++0x standard, it seems like the implicit conversion of a const char * to a string should be considered when considering if f(string &&) is viable, just as when passing a const lvalue ref arguments. Section 13.3 (overload resolution) doesn't differentiate between rvalue refs and const references in too many places. Also, it seems that the rule that prevents lvalues from binding to rvalue references (13.3.3.1.4/3) shouldn't apply if there's an intermediate temporary - after all, it's perfectly safe to move from the temporary. Is this: Me misreading/misunderstand the standard, where the implemented behavior is the intended behavior, and there's some good reason why my example should behave the way it does? A mistake that the compiler vendors have somehow all made? Or a mistake based on common implementation strategies? Or a mistake in e.g. GCC (where this lvalue/rvalue reference binding rule was first implemented), that was copied by other vendors? A defect in the standard, or an unintended consequence, or something that should be clarified?

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