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  • What's correct way to remove a boost::shared_ptr from a list?

    - by Catskul
    I have a std::list of boost::shared_ptr<T> and I want to remove an item from it but I only have a pointer of type T* which matches one of the items in the list. However I cant use myList.remove( tPtr ) I'm guessing because shared_ptr does not implement == for its template argument type. My immediate thought was to try myList.remove( shared_ptr<T>(tPtr) ) which is syntactically correct but it will crash from a double delete since the temporary shared_ptr has a separate use_count. std::list< boost::shared_ptr<T> > myList; T* tThisPtr = new T(); // This is wrong; only done for example code. // stand-in for actual code in T using // T's actual "this" pointer from within T { boost::shared_ptr<T> toAdd( tThisPtr ); // typically would be new T() myList.push_back( toAdd ); } { //T has pointer to myList so that upon a certain action, // it will remove itself romt the list //myList.remove( tThisPtr); //doesn't compile myList.remove( boost::shared_ptr<T>(tThisPtr) ); // compiles, but causes // double delete } The only options I see remaining are to use std::find with a custom compare, or to loop through the list brute force and find it myself, but it seems there should be a better way. Am I missing something obvious, or is this just too non-standard a use to be doing a remove the clean/normal way?

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  • Reading email address from contacts fails with weird memory issue

    - by CapsicumDreams
    Hi all, I'm stumped. I'm trying to get a list of all the email address a person has. I'm using the ABPeoplePickerNavigationController to select the person, which all seems fine. I'm setting my ABRecordRef personDealingWith; from the person argument to - (BOOL)peoplePickerNavigationController:(ABPeoplePickerNavigationController *)peoplePicker shouldContinueAfterSelectingPerson:(ABRecordRef)person property:(ABPropertyID)property identifier:(ABMultiValueIdentifier)identifier { and everything seems fine up till this point. The first time the following code executes, all is well. When subsequently run, I can get issues. First, the code: // following line seems to make the difference (issue 1) // NSLog(@"%d", ABMultiValueGetCount(ABRecordCopyValue(personDealingWith, kABPersonEmailProperty))); // construct array of emails ABMultiValueRef multi = ABRecordCopyValue(personDealingWith, kABPersonEmailProperty); CFIndex emailCount = ABMultiValueGetCount(multi); if (emailCount 0) { // collect all emails in array for (CFIndex i = 0; i < emailCount; i++) { CFStringRef emailRef = ABMultiValueCopyValueAtIndex(multi, i); [emailArray addObject:(NSString *)emailRef]; CFRelease(emailRef); } } // following line also matters (issue 2) CFRelease(multi); If compiled as written, the are no errors or static analysis problems. This crashes with a *** -[Not A Type retain]: message sent to deallocated instance 0x4e9dc60 error. But wait, there's more! I can fix it in either of two ways. Firstly, I can uncomment the NSLog at the top of the function. I get a leak from the NSLog's ABRecordCopyValue every time through, but the code seems to run fine. Also, I can comment out the CFRelease(multi); at the end, which does exactly the same thing. Static compilation errors, but running code. So without a leak, this function crashes. To prevent a crash, I need to haemorrhage memory. Neither is a great solution. Can anyone point out what's going on?

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  • Adding custom methods to a subclassed NSManagedObject

    - by CJ
    I have a Core Data model where I have an entity A, which is an abstract. Entities B, C, and D inherit from entity A. There are several properties defined in entity A which are used by B, C, and D. I would like to leverage this inheritance in my model code. In addition to properties, I am wondering if I can add methods to entity A, which are implemented in it's sub-entities. For example: I add a method to the interface for entity A which returns a value and takes one argument I add implementations of this method to A, B, C, D Then, I call executeFetchRequest: to retrieve all instances of B I call the method on the objects retrieved, which should call the implementation of the method contained in B's implementation I have tried this, but when calling the method, I receive: [NSManagedObject methodName:]: unrecognized selector sent to instance I presume this is because the objects returned by executeFetchRequest: are proxy objects of some sort. Is there any way to leverage inheritance using subclassed NSManagedObjects? I would really like to be able to do this, otherwise my model code would be responsible for determining what type of NSManagedObject it's dealing with and perform special logic according to the type, which is undesirable. Any help is appreciated, thanks in advance.

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  • Passing arguments to objects created using the new operator?

    - by Abhijit
    Hi guys, I have a small C++ problem to which I don't know the best solution. I have two classes A and B as follows: class A { int n; B* b; public: A(int num): n(num) { b = new B[n]; for (int i = 0; i < n; i++) { b[i].setRef(this); } } ~A() { delete [] b; } }; class B { A* a; public: B() { } B(A* aref) { a = aref; } void setRef(A* aref) { a = aref; } }; I am creating an object of class A by passing to its constructor the number of objects of class B I want to be created. I want every object of class B to hold a pointer to the class A object that creates it. I think the best way to do this would be by passing the pointer to the class A object as a constructor argument to the class B object. However, since I'm using the new operator, the no-args constructor for class B is called. As a result, the only solution I can see here is calling the setRef(A*) method for every object of class B after it has been constructed using the new operator. Is there a better solution/design pattern that would be more applicable here? Would using placement new for class B be a better solution? Thanks in advance for your help.

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  • Help passing reference to class subroutine in Perl.

    - by stephenmm
    I am trying to pass a routine to another subroutine within a Perl module. But when I pass the sub reference the passed in ref no longer has the object data. Maybe its not possible to do it this way. The line I have a question about is the "unless" lines below: sub get_flag_end { my $self = shift; return ( -e "$self->{file}" ); } sub wait_for_end { my $self = shift; my $timeout = shift; my $poll_interval = shift; # Is it even possible to pass the oject subroutine and retain the objects data? #unless ( $self->timeout( $timeout, $poll_interval, $self->get_flag_end ) ) { # does not work unless ( $self->timeout( $timeout, $poll_interval, \&get_flag_end ) ) { # call happens but members are empty die "!!!ERROR!!! Timed out while waiting for wait_for_end: timeout=$timeout, poll_interval=$poll_interval \n"; } } sub timeout { my $self = shift; my $timeout = shift; my $poll_interval = shift; my $test_condition = shift; until ($test_condition->() || $timeout <= 0) { $timeout -= $poll_interval; sleep $poll_interval; } return $timeout > 0; # condition was met before timeout } I know that I could change the "get_flag_end" routine to take the value as an argument to the subroutine but what if there was a bunch of stuff done in "get_flag_end" and I needed more members from the object. I simplified the code a bit to make it a little easier to follow.

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  • algorithm || method to write prog

    - by fatai
    I am one of the computer science student. My wonder is everyone solve problem with different or same method, but actually I dont know whether they use method or I dont know whether there are such common method to approach problem. All teacher give us problem which in simple form sometimes, but they dont introduce any approach or method(s) so that we can first choose method then apply that one to problem , afterward find solution then write code. I have found one method when I failed the course, More accurately, When I counter problem in language , I will get more paper and then ; first, input/ output step ; my prog will take this / these there argument(s) and return namely X , ex : in c, input length is not known and at same type , so I must use pointer desired output is in form of package , so use structure second, execution part ; in that step , I am writing all step which are goes to final output ex : in python ; 1.) [ + , [- , 4 , [ * , 1 , 2 ]], 5] 2.) [ + , [- , 4 , 2 ],5 ] 3.) [ + , 2 , 5] 4.) 7 ==> return 7 third, I will write test code ex : in c++ input : append 3 4 5 6 vector_x remove 0 1 desired output vector_x holds : 5 6 But now, I wonder other method ; used to construct class :::: for c++ , python, java used to communicate classes / computers used for solving embedded system problem ::::: for c Why I wonder , because I learn if you dont costruct algorithm on paper, you may achieve your goal. Like no money no lunch , I can say no algorithm no prog therefore , feel free when you write your own method , a way which is introduced by someone else but you are using and you find it is so efficient

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  • How does the overall view hierarchy change when using UIKit view manipulations?

    - by executor21
    I've been trying to figure out what happens in the view hierarchy when methods like pushViewController:animated, presentModalViewController:animated, and tab switches in UITabBarViewController are used, as well as UIAlertView and UIActionSheet. (Side note: I'm doing this because I need to know whether a specific UIView of my creation is visible on screen when I do not know anything about how it or its superview may have been added to the view hierarchy. If someone knows a good way to determine this, I'd welcome the knowledge.) To figure it out, I've been logging out the hierarchy of [[UIApplication sharedApplication] keyWindow] subviews in different circumstances. Is the following correct: When a new viewController is pushed onto the stack of a UINavigationController, the old viewController's view is no longer in the view hierarchy. That is, only the top view controller's view is a subview of UINavigationController's view (according to logs, it's actually several private classes such as UILayoutContainerView). Are the views of view controllers below the top controller of the stack actually removed from the window? A very similar thing happens when a new viewController is presented via presentModalViewController:animated. The new viewController's view is the only subview of the kew window. Is this correct? The easiest thing to understand: a UIAlertView creates its own window and makes it key. The strangest thing I encountered: a UIActionSheet is shown via showInView: method, the actionSheet isn't in the view hierarchy at all. It's not a subview of the view passed as an argument to showInView:, it isn't added as a subview of the key window, and it doesn't create its own window. How does it appear, then? I haven't tried this yet, so I'd like to know what happens in the keyWindow hierarchy when tabs in a UITabBarController are switched. Is the view of the selected UIViewController moved to the top, or does it work like with pushViewController:animated and presentModalViewController:animated, where only the displayed view is in the window hierarchy?

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  • How to pass parameters to manage_shared_memory.construct() in Boost.Interprocess

    - by recipriversexclusion
    I've stared at the Boost.Interprocess documentation for hours but still haven't been able to figure this out. In the doc, they have an example of creating a vector in shared memory like so: //Define an STL compatible allocator of ints that allocates from the managed_shared_memory. //This allocator will allow placing containers in the segment typedef allocator<int, managed_shared_memory::segment_manager> ShmemAllocator; //Alias a vector that uses the previous STL-like allocator so that allocates //its values from the segment typedef vector<int, ShmemAllocator> MyVector; int main(int argc, char *argv[]) { //Create a new segment with given name and size managed_shared_memory segment(create_only, "MySharedMemory", 65536); //Initialize shared memory STL-compatible allocator const ShmemAllocator alloc_inst (segment.get_segment_manager()); //Construct a vector named "MyVector" in shared memory with argument alloc_inst MyVector *myvector = segment.construct<MyVector>("MyVector")(alloc_inst); Now, I understand this. What I'm stuck is how to pass a second parameter to segment.construct() to specify the number of elements. The interprocess document gives the prototype for construct() as MyType *ptr = managed_memory_segment.construct<MyType>("Name") (par1, par2...); but when I try MyVector *myvector = segment.construct<MyVector>("MyVector")(100, alloc_inst); I get compilation errors. My questions are: Who actually gets passed the parameters par1, par2 from segment.construct, the constructor of the object, e.g. vector? My understanding is that the template allocator parameter is being passed. Is that correct? How can I add another parameter, in addition to alloc_inst that is required by the constructor of the object being created in shared memory? There's very little information other than the terse Boost docs on this.

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  • .NET: Problems creating email attachment from MemoryStream.

    - by David
    Hi all I'm using the following method to create an attachment from a MemoryStream: public void AddAttachment(Stream stream, string filename, string mimeType) { byte[] buffer = ((MemoryStream) stream).GetBuffer(); Attachment attachment = new Attachment(stream, filename, mimeType); _mail.Attachments.Add(attachment); } Note that the first line is not necessary isn't necessary for the attachment functionality, it's just useful to have the byte[] handy during debugging so that I can see how big it is. (It generally has around 80,000 elements.) The code runs fine and the email is sent. When Outlook receives the email, in the Inbox it displays the attachment symbol, but when you go into the email the attachment isn't there. Unfortunately I don't have access to the mail server to find out more about the email, e.g. what the attachment looks like, its size etc. Can anyone suggest what properties of the MemoryStream argument might tell me if it is in some way invalid for attachment? Or think of anything else I might try? Thank you. David

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  • Plotting andrews curves of subsets of a data frame on the same plot

    - by user2976477
    I have a data frame of 12 columns and I want to plot andrews curves in R of this data, basing the color of the curves on the 12th columns. Below are a few samples from the data (sorry the columns are not aligned with the numbers) Teacher_explaining Teacher_enthusiastic Teacher_material_interesting Material_stimulating Material_useful Clear_marking Marking_fair Feedback_prompt Feedback_clarifies Detailed_comments Notes Year 80 80 80 80 85 85 80 80 80 80 70 3 70 60 30 40 70 60 30 40 70 0 30 3 100 90 90 80 80 100 100 90 100 100 100 MSc 85 85 85 90 90 70 90 50 70 80 100 MSc 90 50 90 90 90 70 100 50 80 100 100 4 100 80 80 75 90 80 80 50 80 80 90 3 From this data I tried to plot andrews curves using the code below: install.packages("andrews") library(andrews) col <- as.numeric(factor(course[,12])) andrews(course[,1:12], clr = 12) However, the 12th column has three groups (3 types of responses) and I want to group two of them and then plot the andrews curve of the data, without editing my data frame in Excel. x <- subset(course, Year == "MSc" & "4") y <- subset(course, Year == "3") I tried the above code, but my argument for x don't work. "MSc", "3" and "4" are the groups in the 12th column, and I want to group MSc and 4 so that their Andrews curves have the same color. If you have any idea how to do this, please let me know.

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  • Can I recover lost commits in a SVN repository using a local tracking git-svn branch?

    - by Ian Stevens
    A SVN repo I use git-svn to track was recently corrupted and a backup was recovered. However, a week's worth of commits were lost in the recovery. Is it possible to recover those lost commits using git-svn dcommit on my local git repo? Is it sufficient to run git-svn dcommit with the SHA1 of the last recovered commit in SVN? eg. > svn info http://tracked-svn/trunk | sed -n "s/Revision: //p" 252 > git log --grep="git-svn-id:.*@252" --format=oneline | cut -f1 -d" " 55bb5c9cbb5fe11a90ec2e9e1e0c7c502908cf9a > git svn dcommit 55bb5c9cbb5fe11a90ec2e9e1e0c7c502908cf9a Or will the git-svn-id need to be stripped from the intended commits? I tried this using --dry-run but couldn't tell whether it would try to submit all commits: > git svn dcommit --verbose --dry-run 55bb5c9cbb5fe11a90ec2e9e1e0c7c502908cf9a Committing to http://tracked-svn/trunk ... dcommitted on a detached HEAD because you gave a revision argument. The rewritten commit is: 55bb5c9cbb5fe11a90ec2e9e1e0c7c502908cf9a Thanks for your help.

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  • With PascalMock how do I mock a method with an untyped out parameter and an open array parameter?

    - by Oliver Giesen
    I'm currently in the process of getting started with unit testing and mocking for good and I stumbled over the following method that I can't seem to fabricate a working mock implementation for: function GetInstance(const AIID: TGUID; out AInstance; const AArgs: array of const; const AContextID: TImplContextID = CID_DEFAULT): Boolean; (TImplContextID is just an alias for Integer) I thought it would have to look something like this: function TImplementationProviderMock.GetInstance( const AIID: TGUID; out AInstance; const AArgs: array of const; const AContextID: TImplContextID): Boolean; begin Result := AddCall('GetInstance') .WithParams([@AIID, AContextID]) .ReturnsOutParams([AInstance]) .ReturnValue; end; But the compiler complains about the .ReturnsOutParams([AInstance]) saying "Bad argument type in variable type array constructor.". Also I haven't found a way to specify the open array parameter AArgs at all. Also, is using the @-notation for the TGUID-typed parameter the right way to go? Is it possible to mock this method with the current version of PascalMock at all?

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  • Why is VB6 still so widely used?

    - by Uri
    Note that this question is not meant to start an argument, I am genuinely curious: Back in the 90s I used to work for a large CPU maker and we were building some debuggers. All our core logic was in C++, but the GUI was made in VB6. We couldn't figure out MFC and it was too much a hassle. We glued together VB6 and C++ using COM which we created via ATL. Fast forward to 2009, having been mostly in the Java world I am looking at job boards and seeing more VB6 jobs than I expected. I genuinely thought that VB6 was extinct, especially since VB.NET supposedly solved a lot of the problems with the VB6 which at the time felt a lot like a scripting language than a true OOP language. So what happened? Why is new code still written in it? Isn't there a better way to glue C++ and VB.NET? Note that I haven't used VB.NET, I just understand that it is a much more "stricter" language than VB6 was. Even with Option Explicit or whatever it was.

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  • Passing row from UIPickerView to integer CoreData attribute

    - by Gordon Fontenot
    I'm missing something here, and feeling like an idiot about it. I'm using a UIPickerView in my app, and I need to assign the row number to a 32-bit integer attribute for a Core Data object. To do this, I am using this method: -(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component { object.integerValue = row; } This is giving me a warning: warning: passing argument 1 of 'setIntegerValue:' makes pointer from integer without a cast What am I mixing up here? --EDIT 1-- Ok, so I can get rid of the errors by changing the method to do the following: NSNumber *number = [NSNumber numberWithInteger:row]; object.integerValue = rating; However, I still get a value of 0 for object.integerValue if I use NSLog to print it out. object.integerValue has a max value of 5, so I print out number instead, and then I'm getting a number above 62,000,000. Which doesn't seem right to me, since there are 5 rows. If I NSLog the row variable, I get a number between 0 and 5. So why do I end up with a completely different number after casting the number to NSNumber?

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  • How can I test for an empty Breeze predicate?

    - by Megan
    I'm using Breeze to filter data requested on the client. My code looks a little like this: Client - Creating Filter Predicate var predicates = []; var criteriaPredicate = null; $.each(selectedFilterCriteria(), function (index, item) { criteriaPredicate = (index == 0) ? breeze.Predicate.create('criteriaId', breeze.FilterQueryOp.Equals, item) : criteriaPredicate.or('criteriaId', breeze.FilterQueryOp.Equals, item); if (breeze.Predicate.isPredicate(criteriaPredicate)) { predicates.push(criteriaPredicate); } // Repeat for X Filter Criteria var filter = breeze.Predicate.and(predicates); return context.getAll(filter, data); Client - Context Query function getAll(predicate, dataObservable) { var query = breeze.EntityQuery.from('Data'); if (breeze.Predicate.isPredicate(predicate)) { query = query.where(predicate); } return manager.executeQuery(query).then(success).fail(failure); } Issue I'm having an issue with the request because, if there are no filters set, I apply an "empty" predicate (due to the var filter = breeze.Predicate.and([]) line) resulting in a request like http://mysite/api/app/Data?$filter=. The request is an invalid OData query since the value of the $filter argument cannot be empty. Is there a good way for me to check for an empty predicate? I know I can refactor my client code to not use a predicate unless there is at least one filterable item, but I thought I would check first to see if I overlooked some property or method on the Breeze Predicate.

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  • Basic syntax for an animation loop?

    - by Moshe
    I know that jQuery, for example, can do animation of sorts. I also know that at the very core of the animation, there must me some sort of loop doing the animation. What is an example of such a loop? A complete answer should ideally answer the following questions: What is a basic syntax for an effective animation recursion that can animate a single property of a particular object at a time? The function should be able to vary its target object and property of the object. What arguments/parameters should it take? What is a good range of reiterating the loop? In milliseconds? (Should this be a parameter/argument to the function?) REMEMBER: The answer is NOT necessarily language specific, but if you are writing in a specific language, please specify which one. Error handling is a plus. {Nothing is more irritating (for our purposes) than an animation that does something strange, like stopping halfway through.} Thanks!

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  • Sort and limit queryset by comment count and date using queryset.extra() (django)

    - by thornomad
    I am trying to sort/narrow a queryset of objects based on the number of comments each object has as well as by the timeframe during which the comments were posted. Am using a queryset.extra() method (using django_comments which utilizes generic foreign keys). I got the idea for using queryset.extra() (and the code) from here. This is a follow-up question to my initial question yesterday (which shows I am making some progress). Current Code: What I have so far works in that it will sort by the number of comments; however, I want to extend the functionality and also be able to pass a time frame argument (eg, 7 days) and return an ordered list of the most commented posts in that time frame. Here is what my view looks like with the basic functionality in tact: import datetime from django.contrib.comments.models import Comment from django.contrib.contenttypes.models import ContentType from django.db.models import Count, Sum from django.views.generic.list_detail import object_list def custom_object_list(request, queryset, *args, **kwargs): '''Extending the list_detail.object_list to allow some sorting. Example: http://example.com/video?sort_by=comments&days=7 Would get a list of the videos sorted by most comments in the last seven days. ''' try: # this is where I started working on the date business ... days = int(request.GET.get('days', None)) period = datetime.datetime.utcnow() - datetime.timedelta(days=int(days)) except (ValueError, TypeError): days = None period = None sort_by = request.GET.get('sort_by', None) ctype = ContentType.objects.get_for_model(queryset.model) if sort_by == 'comments': queryset = queryset.extra(select={ 'count' : """ SELECT COUNT(*) AS comment_count FROM django_comments WHERE content_type_id=%s AND object_pk=%s.%s """ % ( ctype.pk, queryset.model._meta.db_table, queryset.model._meta.pk.name ), }, order_by=['-count']).order_by('-count', '-created') return object_list(request, queryset, *args, **kwargs) What I've Tried: I am not well versed in SQL but I did try just to add another WHERE criteria by hand to see if I could make some progress: SELECT COUNT(*) AS comment_count FROM django_comments WHERE content_type_id=%s AND object_pk=%s.%s AND submit_date='2010-05-01 12:00:00' But that didn't do anything except mess around with my sort order. Any ideas on how I can add this extra layer of functionality? Thanks for any help or insight.

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  • boost::lambda bind expressions can't get bind to string's empty() to work

    - by navigator
    Hi, I am trying to get the below code snippet to compile. But it fails with: error C2665: 'boost::lambda::function_adaptor::apply' : none of the 8 overloads could convert all the argument types. Sepcifying the return type when calling bind does not help. Any idea what I am doing wrong? Thanks. #include <boost/lambda/lambda.hpp> #include <boost/lambda/bind.hpp> #include <string> #include <map> int main() { namespace bl = boost::lambda; typedef std::map<int, std::string> types; types keys_and_values; keys_and_values[ 0 ] = "zero"; keys_and_values[ 1 ] = "one"; keys_and_values[ 2 ] = "Two"; std::for_each( keys_and_values.begin(), keys_and_values.end(), std::cout << bl::constant("Value empty?: ") << std::boolalpha << bl::bind(&std::string::empty, bl::bind(&types::value_type::second, _1)) << "\n"); return 0; }

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  • Java and .net interoperability

    - by dineshrekula
    I have a c# program through which i am opening cmd window as a a process. in this command window i am running a batch file. i am redirecting the output of that batch file commands to a Text File. When i run my application everything seems to be ok. But few times, Application is giving some error like "Can't access the file. it's being used by another application" at the same time cmd window is not getting closed. If we close the cmd process through the Task Manager, then it's writing the content to the file and getting closed. Even though i closed the cmd process, still file handle is not getting released. so that i am not able to run the application next time onwards.Always it's saying Can't access the file. Only after restarting the system, it's working. Here is my code: Process objProcess = new Process(); ProcessStartInfo objProInfo = new ProcessStartInfo(); objProInfo.WindowStyle = ProcessWindowStyle.Maximized; objProInfo.UseShellExecute = true; objProInfo.FileName = "Batch file path" objProInfo.Arguments = "Some Arguments"; if (Directory.Exists(strOutputPath) == false) { Directory.CreateDirectory(strOutputPath); } objProInfo.CreateNoWindow = false; objProcess.StartInfo = objProInfo; objProcess.Start(); objProcess.WaitForExit(); test.bat: java classname argument > output.txt Here is my question: I am not able to trace where the problem is.. How we can see the process which holding handle on ant file. Is there any suggestions for Java and .net interoperability

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  • Base class deleted before subclass during python __del__ processing

    - by Oddthinking
    Context I am aware that if I ask a question about Python destructors, the standard argument will be to use contexts instead. Let me start by explaining why I am not doing that. I am writing a subclass to logging.Handler. When an instance is closed, it posts a sentinel value to a Queue.Queue. If it doesn't, a second thread will be left running forever, waiting for Queue.Queue.get() to complete. I am writing this with other developers in mind, so I don't want a failure to call close() on a handler object to cause the program to hang. Therefore, I am adding a check in __del__() to ensure the object was closed properly. I understand circular references may cause it to fail in some circumstances. There's not a lot I can do about that. Problem Here is some simple example code: explicit_delete = True class Base: def __del__(self): print "Base class cleaning up." class Sub(Base): def __del__(self): print "Sub-class cleaning up." Base.__del__(self) x = Sub() if explicit_delete: del x print "End of thread" When I run this I get, as expected: Sub-class cleaning up. Base class cleaning up. End of thread If I set explicit_delete to False in the first line, I get: End of thread Sub-class cleaning up. Exception AttributeError: "'NoneType' object has no attribute '__del__'" in <bound method Sub.__del__ of <__main__.Sub instance at 0x00F0B698>> ignored It seems the definition of Base is removed before the x._del_() is called. The Python Documentation on _del_() warns that the subclass needs to call the base-class to get a clean deletion, but here that appears to be impossible. Can you see where I made a bad step?

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  • Strcpy and malloc issues

    - by mrblippy
    Hi, i am having trouble getting a method relating to a linked list working, i get the errors: assignment makes pointer from integer without a cast and passing argument 1 of âstrcpyâ makes pointer from integer without a cast. i have tried to include all the relevant code, but let me know if you need more info. thanks. struct unit { char code[5]; char *name; node_ptr students; }; typedef struct node *node_ptr; struct node { int student_id; char *studentname; node_ptr next; }; void enrol_student(struct unit u[], int n) { int i, p; int student_id = 0; char code_to_enrol[7]; char buffer[100]; node_ptr studentslist; scanf("%s\n", code_to_enrol); for(i=0; i <= n; i++) { studentslist = u[i].students; if(strcmp(u[i].code ,code_to_enrol)<=0) { scanf("enter student details %d %s\n", &studentID, buffer); p = (char *) malloc (strlen(buffer)+1); strcpy(p, buffer); insert_in_order(student_id, buffer, studentslist); } } } void insert_in_order(int n, char *i, node_ptr list) { node_ptr before = list; node_ptr students = (node_ptr) malloc(sizeof(struct node)); students->ID = n; students->name = *i; while(before->next && (before->next->ID < n)) { before = before->next; } students->next = before->next; before->next = students; }

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  • Munging non-printable characters to dots using string.translate()

    - by Jim Dennis
    So I've done this before and it's a surprising ugly bit of code for such a seemingly simple task. The goal is to translate any non-printable character into a . (dot). For my purposes "printable" does exclude the last few characters from string.printable (new-lines, tabs, and so on). This is for printing things like the old MS-DOS debug "hex dump" format ... or anything similar to that (where additional whitespace will mangle the intended dump layout). I know I can use string.translate() and, to use that, I need a translation table. So I use string.maketrans() for that. Here's the best I could come up with: filter = string.maketrans( string.translate(string.maketrans('',''), string.maketrans('',''),string.printable[:-5]), '.'*len(string.translate(string.maketrans('',''), string.maketrans('',''),string.printable[:-5]))) ... which is an unreadable mess (though it does work). From there you can call use something like: for each_line in sometext: print string.translate(each_line, filter) ... and be happy. (So long as you don't look under the hood). Now it is more readable if I break that horrid expression into separate statements: ascii = string.maketrans('','') # The whole ASCII character set nonprintable = string.translate(ascii, ascii, string.printable[:-5]) # Optional delchars argument filter = string.maketrans(nonprintable, '.' * len(nonprintable)) And it's tempting to do that just for legibility. However, I keep thinking there has to be a more elegant way to express this!

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  • python 'with' statement

    - by Stephen
    Hi, I'm using Python 2.5. I'm trying to use this 'with' statement. from __future__ import with_statement a = [] with open('exampletxt.txt','r') as f: while True: a.append(f.next().strip().split()) print a The contents of 'exampletxt.txt' are simple: a b In this case, I get the error: Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/tmp/python-7036sVf.py", line 5, in <module> a.append(f.next().strip().split()) StopIteration And if I replace f.next() with f.read(), it seems to be caught in an infinite loop. I wonder if I have to write a decorator class that accepts the iterator object as an argument, and define an __exit__ method for it? I know it's more pythonic to use a for-loop for iterators, but I wanted to implement a while loop within a generator that's called by a for-loop... something like def g(f): while True: x = f.next() if test(x): a = x elif test(x): b = f.next() yield [a,x,b] a = [] with open(filename) as f: for x in g(f): a.append(x)

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  • Serial.begin(speed, config) not compiling for Leonardo Board

    - by forgemo
    I would like to configure my serial communication to have no parity, 1 start- and 2 stop-bits. The documentation for Serial.begin(speed, config) states: (...) An optional second argument configures the data, parity, and stop bits. The default is 8 data bits, no parity, one stop bit. The documentation also lists the possible configuration-values. According to my (limited) understanding, I need SERIAL_7N2 or SERIAL_8N2 to meet my requirements. (I'm not sure how the data-bits relate to the the 1-start-bit that I need.) However, I can't even compile because I have no idea how to supply that config value to the begin method. (I don't have much Arduino/C++ experience) I've tried in my code the following two variants: Serial.begin(9600, SERIAL_8N2); Serial.begin(9600, "SERIAL_8N2"); Am I missing something? Additional Information: Serial.begin(speed, config) has been introduced with the latest Arduino 1.0.2 IDE version. The code defining/implementing the begin methods can be found here. HardwareSerial.h HardwareSerial.cpp Edit: According to the replies from PeterJ and borges, the following variant is correct. Serial.begin(9600, SERIAL_8N2); However, it's still not working. I found that the compile error doesn't occur if I change the configured board from my Arduino Leonardo to Arduino uno. Therefore, it could be a bug occurring only with a subset of boards ... or maybe it's not supported?!

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  • TeamCity + HG. Only pull (push?) passing builds

    - by ColoradoMatt
    Feels like with the popularity of continuous integration this one should be a piece of cake but I am stumped. I am setting up TeamCity with HG. I want to be able to push changesets up to a repository that TeamCity watches and runs builds on changes. That's easy. Next, if a build passes, I want that changeset to be pulled into a "clean" repository... one that contains only passing changesets. Should be easy but... TeamCity 6 supports multiple build steps and if any step fails, the rest don't run. My thought was to put a build step at the end that does a pull (or optionally a push?) to get the passing changeset into the clean repository. I am trying to use PsExec to run hg on the box with the repositories. If I try to run just a plain 'hg pull' it can't find the hg.exe even though it is set in the path and I have used the -w flag. I have tried putting a .bat file in the clean repository that takes a revision parameter and it works fine... locally. When I try to run the .bat file remotely (using PsExec) it runs everything fine but it tries to run it on the build agent. Even if I set the -w argument it runs the .bat file there but tries to run the contents on the build agent box. Am I just WAY off in my approach? Seems like this is a pretty obvious thing to do so either my Google skills are waning or no one thinks this is worthy of writing about. Either way, I am stuck in SVN land trying to get out so I would appreciate some help!

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