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• To use the 'I' prefix for interfaces or not to

  - by ng

  That is the question? So how big a sin is it not to use this convention when developing a c# project? This convention is widely used in the .NET class library. However, I am not a fan to say the least, not just for asthetic reasons but I don't think it makes any contribution. For example is IPSec an interface of PSec? Is IIOPConnection An interface of IOPConnection, I usually go to the definition to find out anyway. So would not using this convention cause confusion? Are there any c# projects or libraries of note that drop this convention? Do any c# projects that mix conventions, as unfortunately Apache Wicket does? The Java class libraries have existed without this for many years, I don't feel I have ever struggled to read code without it. Also, should the interface not be the most primitive description? I mean IList<T> as an interface for List<T> in c#, is it not better to have List<T> and LinkedList<T> or ArrayList<T> or even CopyOnWriteArrayList<T>? The classes describe the implementation? I think I get more information here, than I do from List<T> in c#.

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• Using sigprocmask to implement locks

  - by EpsilonVector

  I'm implementing user threads in Linux kernel 2.4, and I'm using ualarm to invoke context switches between the threads. We have a requirement that our thread library's functions should be uninterruptable, so I looked into blocking signals and learned that using sigprocmask is the standard way to do this. However, it looks like I need to do quite a lot to implement this: sigset_t new_set, old_set; sigemptyset(&new_set); sigaddset(&new_set, SIGALRM); sigprocmask(SIG_BLOCK, &new_set, &old_set); This blocks SIGALARM but it does this with 3 function invocations! A lot can happen in the time it takes for these functions to run, including the signal being sent. The best idea I had to mitigate this was temporarily disabling ualarm, like this: sigset_t new_set, old_set; time=ualarm(0,0); sigemptyset(&new_set); sigaddset(&new_set, SIGALRM); sigprocmask(SIG_BLOCK, &new_set, &old_set); ualarm(time, 0); Which is fine except that this feels verbose. Isn't there a better way to do this?

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• ASP.NET GridView "Client-Side Confirmation when Deleting" stopped working on ie - how come?

  - by tarnold

  A few months ago, I have programmed an ASP.NET GridView with a custom "Delete" LinkButton and Client-Side JavaScript Confirmation according to this msdn article: http://msdn.microsoft.com/en-us/library/bb428868.aspx (published in April 2007) or e.g. http://stackoverflow.com/questions/218733/javascript-before-aspbuttonfield-click The code looks like this: <ItemTemplate> <asp:LinkButton ID="deleteLinkButton" runat="server" Text="Delete" OnCommand="deleteLinkButtonButton_Command" CommandName='<%# Eval("id") %>' OnClientClick='<%# Eval("id", "return confirm(\"Delete Id {0}?\")") %>' /> </ItemTemplate> Surprisingly, "Cancel" doesn't work no more with my ie (Version: 6.0.2900.2180.xpsp_sp2_qfe.080814-1242) - it always deletes the row. With Opera (Version 9.62) it still works as expeced and described in the msdn article. More surprisingly, on a fellow worker's machine with the same ie version, it still works ("Cancel" will not delete the row). The generated code looks like <a onclick="return confirm(...);" href="javascript:__doPostBack('...')"> As confirm(...) returns false on "Cancel", I expect the __doPostBack event in the href not to be fired. Are there any strange ie settings I accidentally might have changed? What else could be the cause of this weird behaviour? Or is this a "please reinstall WinXP" issue?

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• Best Practice: Access form elements by HTML id or name attribute?

  - by seth

  As any seasoned JavaScript developer knows, there are many (too many) ways to do the same thing. For example, say you have a text field as follows: <form name="myForm"> <input type="text" name="foo" id="foo" /> There are many way to access this in JavaScript: [1] document.forms[0].elements[0]; [2] document.myForm.foo; [3] document.getElementById('foo'); [4] document.getElementById('myForm').foo; ... and so on ... Methods [1] and [3] are well documented in the Mozilla Gecko documentation, but neither are ideal. [1] is just too general to be useful and [3] requires both an id and a name (assuming you will be posting the data to a server side language). Ideally, it would be best to have only an id attribute or a name attribute (having both is somewhat redundant, especially if the id isn't necessary for any css, and increases the likelihood of typos, etc). [2] seems to be the most intuitive and it seems to be widely used, but I haven't seen it referenced in the Gecko documentation and I'm worried about both forwards compatibility and cross browser compatiblity (and of course I want to be as standards compliant as possible). So what's best practice here? Can anyone point to something in the DOM documentation or W3C specification that could resolve this? Note I am specifically interested in a non-library solution (jQuery/Prototype).

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• Codeigniter Session Data not available in other pages after login

  - by jswat

  So, I have set up a login page that verifies the user's credentials, and then sets codeigniter session data 'email' and 'is_logged_in' and a few other items. The first page after the login, the data is accessible. After that page, I can no longer access the session data. In fact, if I try reloading that first page, the session data is gone. I have tried storing it in the database, storing it unencrypted (bad idea I know, but it was for troubleshooting), and storing it encrypted. I have autoloaded the session library in config.php. Here's an example of the code I'm using to set the session data: $data = array( 'email' => $this->input->post('username'), 'is_logged_in' => true ); $this->session->set_userdata($data); And to retrieve it, I'm using : $this->session->userdata('email'); Or $this->session->userdata('is_logged_in'); I've done lots of work with PHP and cookies, and sessions before, but this is my first project with Codeigniter and I'm perplexed. Could it have something to do with directory issues? I have the login page and process controlled by a 'login' controller, and then it redirects to a 'site' controller. Thanks for your help, and please let me know if I need to clarify anything.

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• Generating a canonical path

  - by Joel

  Does any one know of any Java libraries I could use to generate canonical paths (basically remove back-references). I need something that will do the following: Raw Path - Canonical Path /../foo/ -> /foo /foo/ -> /foo /../../../ -> / /./foo/./ -> /foo //foo//bar -> /foo/bar //foo/../bar -> /bar etc... At the moment I lazily rely on using: new File("/", path).getCanonicalPath(); But this resolves the path against the actual file system, and is synchronised. java.lang.Thread.State: BLOCKED (on object monitor) at java.io.ExpiringCache.get(ExpiringCache.java:55) - waiting to lock <0x93a0d180> (a java.io.ExpiringCache) at java.io.UnixFileSystem.canonicalize(UnixFileSystem.java:137) at java.io.File.getCanonicalPath(File.java:559) The paths that I am canonicalising do not exist on my file system, so just the logic of the method will do me fine, thus not requiring any synchronisation. I'm hoping for a well tested library rather than having to write my own.

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• What is your personal approach/take on commenting?

  - by Trae

  Duplicate What are your hard rules about commenting? A Developer I work with had some things to say about commenting that were interesting to me (see below). What is your personal approach/take on commenting? "I don't add comments to code unless its a simple heading or there's a platform-bug or a necessary work-around that isn't obvious. Code can change and comments may become misleading. Code should be self-documenting in its use of descriptive names and its logical organization - and its solutions should be the cleanest/simplest way to perform a given task. If a programmer can't tell what a program does by only reading the code, then he's not ready to alter it. Commenting tends to be a crutch for writing something complex or non-obvious - my goal is to always write clean and simple code." "I think there a few camps when it comes to commenting, the enterprisey-type who think they're writing an API and some grand code-library that will be used for generations to come, the craftsman-like programmer that thinks code says what it does clearer than a comment could, and novices that write verbose/unclear code so as to need to leave notes to themselves as to why they did something."

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• Memcache error: Failed reading line from stream (0) Array

  - by daviddripps

  I get some variation of the following error when our server gets put under any significant load. I've Googled for hours about it and tried everything (including upgrading to the latest versions and clean installs). I've read all the posts about it here on SA, but can't figure it out. A lot of people are having the same problem, but no one seems to have a definitive answer. Any help would be greatly appreciated. Thanks in advance. Fatal error: Uncaught exception 'Zend_Session_Exception' with message 'Zend_Session::start() - /var/www/trunk/library/Zend/Cache/Backend/Memcached.php(Line:180): Error #8 Memcache::get() [memcache.get]: Server localhost (tcp 11211) failed with: Failed reading line from stream (0) Array We have a copy of our production environment for testing and everything works great until we start load-testing. I think the biggest object stored is about 170KB, but it will probably be about 500KB when all is said and done (well below the 1MB limit). Just FYI: Memcache gets hit about 10-20 times per page load. Here's the memcached settings: PORT="11211" USER="memcached" MAXCONN="1024" CACHESIZE="64" OPTIONS="" I'm running Memcache 1.4.5 with version 2.2.6 of the PHP-memcache module. PHP is version 5.2.6. memcache details from php -i: memcache memcache support = enabled Active persistent connections = 0 Version = 2.2.6 Revision = $Revision: 303962 $ Directive = Local Value = Master Value memcache.allow_failover = 1 = 1 memcache.chunk_size = 8192 = 8192 memcache.default_port = 11211 = 11211 memcache.default_timeout_ms = 1000 = 1000 memcache.hash_function = crc32 = crc32 memcache.hash_strategy = standard = standard memcache.max_failover_attempts = 20 = 20 Thanks everyone

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• What is the rationale to not allow overloading of C++ conversions operator with non-member function

  - by Vicente Botet Escriba

  C++0x has added explicit conversion operators, but they must always be defined as members of the Source class. The same applies to the assignment operator, it must be defined on the Target class. When the Source and Target classes of the needed conversion are independent of each other, neither the Source can define a conversion operator, neither the Target can define a constructor from a Source. Usually we get it by defining a specific function such as Target ConvertToTarget(Source& v); If C++0x allowed to overload conversion operator by non member functions we could for example define the conversion implicitly or explicitly between unrelated types. template < typename To, typename From > operator To(const From& val); For example we could specialize the conversion from chrono::time_point to posix_time::ptime as follows template < class Clock, class Duration> operator boost::posix_time::ptime( const boost::chrono::time_point<Clock, Duration>& from) { using namespace boost; typedef chrono::time_point<Clock, Duration> time_point_t; typedef chrono::nanoseconds duration_t; typedef duration_t::rep rep_t; rep_t d = chrono::duration_cast<duration_t>( from.time_since_epoch()).count(); rep_t sec = d/1000000000; rep_t nsec = d%1000000000; return posix_time::from_time_t(0)+ posix_time::seconds(static_cast<long>(sec))+ posix_time::nanoseconds(nsec); } And use the conversion as any other conversion. For a more complete description of the problem, see here or on my Boost.Conversion library.. So the question is: What is the rationale to non allow overloading of C++ conversions operator with non-member functions?

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• C# Cast Class to Overridden Class

  - by Nathan Tornquist

  I have a class Application that I need to override with INotifyPropertyChanged events. I have written the logic to override the original class and ended up creating SuperApplication I am pulling the data from a library though, and cannot change the loading logic. I just need a way to get the data from the original class into my superClass. I've tried things like superClass = (SuperApplication)standardClass; but it hasn't worked. How would I go about doing this? If it helps, this is the code I'm using to override the original class: public class SuperCreditApplication : CreditApplication { public SuperCreditApplicant Applicant { get; set; } public SuperCreditApplicant CoApplicant { get; set; } } public class SuperCreditApplicant : CreditApplicant { public SuperProspect Prospect { get; set; } } public class SuperProspect : Prospect, INotifyPropertyChanged { public State DriverLicenseState { get { return DriverLicenseState; } set { DriverLicenseState = value; OnPropertyChanged("DriverLicenseState"); } } public event PropertyChangedEventHandler PropertyChanged; private void OnPropertyChanged(string propertyName) { if (PropertyChanged != null) { PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } } }

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• Problem with NSString

  - by Kassar

  I have a problem with NSString in dynamic binding ... I manipulate with Facebook library, when i'll share my story i should make an instance of FBStreamDialog and charge its attributes with values of the story then show it, like this: FBStreamDialog* dialog = [[[FBStreamDialog alloc] init]autorelease]; dialog.delegate = self; dialog.userMessagePrompt = @"prompt"; NSString* sss=@"{ \"name\":\"%@\", \"href\":\"%@\", \"caption\":\"%@\", \"description\":\"%@\" , \"media\":[{ \"type\":\"image\", \"src\":\"%@\", \"href\":\"%@\" }] }"; dialog.attachment = [NSString stringWithFormat:sss,@"title",@"http://www.docs.com/hi.html",@"caption",@"summary",@"http://www.images.com/206.jpg",@"http://www.images.com/206.jpg"]; NSLog(@"ATTACHMENT: %@",dialog.attachment); The code above is running well. But my problem is when i want to charge these attributes dynamically like this: BStreamDialog* dialog = [[[FBStreamDialog alloc] init]autorelease]; dialog.delegate = self; dialog.userMessagePrompt = @"prompt"; NSString* sss=@"{ \"name\":\"%@\", \"href\":\"%@\", \"caption\":\"%@\", \"description\":\"%@\" , \"media\":[{ \"type\":\"image\", \"src\":\"%@\", \"href\":\"%@\" }] }"; dialog.attachment = [NSString stringWithFormat:sss,story.title,story.link,story.caption,story.summary,story.imagelink,story.imagelink]; NSLog(@"ATTACHMENT: %@",dialog.attachment); It's running without crash but it doesn't share the story it share a blank one !!! Although, it shows in the console (output of NSLog) the value of attachment is true !!! Could you plz help me. Sorry for my english.

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• Cross-platform iteration of Unicode string

  - by kizzx2

  I want to iterate each character of a Unicode string, treating each surrogate pair and combining character sequence as a single unit (one grapheme). Example The text "??????" is comprised of the code points: U+0928, U+092E, U+0938, U+094D, U+0924, U+0947, of which, U+0938 and U+0947 are combining marks. static void Main(string[] args) { const string s = "??????"; Console.WriteLine(s.Length); // Ouptuts "6" var l = 0; var e = System.Globalization.StringInfo.GetTextElementEnumerator(s); while(e.MoveNext()) l++; Console.WriteLine(l); // Outputs "4" } So there we have it in .NET. We also have Win32's CharNextW() #include <Windows.h> #include <iostream> #include <string> int main() { const wchar_t * s = L"??????"; std::cout << std::wstring(s).length() << std::endl; // Gives "6" int l = 0; while(CharNextW(s) != s) { s = CharNextW(s); ++l; } std::cout << l << std::endl; // Gives "4" return 0; } Question Both ways I know of are specific to Microsoft. Are there portable ways to do it? I heard about ICU but I couldn't find something related quickly (UnicodeString(s).length() still gives 6). Would be an acceptable answer to point to the related function/module in ICU. C++ doesn't have a notion of Unicode, so a lightweight cross-platform library for dealing with these issues would make an acceptable answer.

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• MSVC 2003 doesn't see any definitions from a nested include file

  - by ezpresso

  I have a piece of code with COM class declaration as follows: #include "PathTypes.h" MIDL_INTERFACE("552C7555-0555-4444-BA86-56CF39AAFFFF") IPathCalc : public IUnknown { virtual HRESULT STDMETHODCALLTYPE GetLocation( /* [retval][out] */ GeoLocation* pLoc) = 0; virtual HRESULT STDMETHODCALLTYPE SetLocation( /* [in] */ GeoLocation* pLoc) = 0; ... }; Below is the contents of PathTypes.h file: #if !defined(PATHCALC_TYPES_INCLUDED) #define PATHCALC_TYPES_INCLUDED #include "libastro/AstronomyStructs.h" #endif And the libastro/AstronomyStructs.h from an external cross-platform library: #ifndef _ASTRONOMY_STRUCTS_INCLUDED #define _ASTRONOMY_STRUCTS_INCLUDED typedef struct { double lattitude; double longitude; } GeoLocation; ... #endif /* _ASTRONOMY_STRUCTS_INCLUDED */ When I'm trying to build this code with g++ everything goes well. That's not the case with MSVC 2003 which returns error C2061: syntax error : identifier 'GeoLocation'. Seems like MSVC doesn't "see" the definitions from the libastro/AstronomyStructs.h file. When I replace #include "PathTypes.h" with #include "libastro/AstronomyStructs.h" the code compiles without errors. How to make MSVC 2003 to actually "see" the definitions from the nested include files?

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• jQuery "best practices" is an oxymoron [closed]

  - by n00b

  jQuery "best practices", oxymoron for several reasons sadly To speak candidly, the entire jQuery library has a HIGHLY inconsistent API, and virtually no coding standards. It's basically a subset of JavaScript, a new language if you will, which is probably the most confusing part for normal javascript developers. In my opinion, use normal JavaScript where possible to save on memory consumption. Or, better yet, use a professional tool like YUI. If you already come from a javascript background, you will appreciate it much more than jQuery because it doesn't have n00b wrappers around everything. In tools like YUI, you interact directly with the native DOM to do things, instead of a super-jQuery object that tries to do everything. I'll get voted down for saying the truth. Don't get me wrong, jQuery is cool if you wanna throw something flashy up quick, but if you're going to build a larger app you're going to need a more refined tool (especially since jQuery leaks memory like no other once you start chaining too much things). jQuery does have one of the lowest learning curves, and you won't outgrow it for awhile, but when you do it will be highly apparent and tedious to merge to something else. over 60 years programming experience someone clean this up and community wiki please

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• How can I embed images within my application and use them in HTML control?

  - by Atara

  Is there any way I can embed the images within my exe (as resource?) and use it in generated HTML ? Here are the requirements: A. I want to show dynamic HTML content (e.g. using webBrowser control, VS 2008, VB .Net, winForm desktop application) B. I want to generate the HTML on-the-fly using XML and XSL (file1.xml or file2.xml transformed by my.xsl) C. The HTML may contain IMG tags (file1.gif and or file2.gif according to the xml+xsl transformation) and here comes the complicated one: D. All these files (file1.xml, file2.xml, my.xsl, file1.gif, file2.gif) should be embedded in one exe file. I guess the XML and XSL can be embedded resources, and I can read them as stream, but what ways do I have to reference the image within the HTML ? <IMG src="???" /> I do not want to use absolute path and external files. If the image files are resources, can I use relative path? Relative to what? (I can use BASE tag, and then what?) Can I use stream as in email messages? If so, where can I find the format I need to use? http://www.websiteoptimization.com/speed/tweak/inline-images/ are browser dependent. What is the browser used by webBrowser control? IE? what version? Does it matter if I use GIF or JPG or BMP (or any other image format) for the images? Does it matter if I use mshtml library and not the regular webBrowser control? (currently I use http://www.itwriting.com/htmleditor/index.php ) Does it matter if I upgrade to VS 2010 ? Thanks, Atara

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• How can I accelerate the generation of the an MD5 Checksum within vb.net?

  - by Richard

  I'm working with some very large files residing on P2 (Panasonic) cards. Part of the process we employ is to first generate a checksum of the file we are going to copy, then copy the file, then run a checksum on the file to confirm that it copied OK. The problem is, is that files are large (70 GB+) and take a long time to complete. It's an issue since we will eventually be dealing with thousands of these files. I would like to find a faster way to generate the checksum other than using the System.Security.Cryptography.MD5CryptoServiceProvider I don't care if this means using a specialized hardware card, provided it works and is not to ungodly expensive. I would prefer to have a method of encoding that provided some feedback as to how far the process has gone along so I can display it like I do now. The application is written in vb.net. I would prefer to be able to use it as component, library, reference within my application, but I'm willing to call an outside application if there is enough improvement in the speed of generating the checksum. Needless to say, the checksum must be consistent and correct. :-) Thank you in advance for your time and efforts, Richard

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• unhandled exception Handler in .Net 3.5 SP1

  - by Ruony

  Hi. I'm converting my own web browser use WPF from Windows XP to Windows 7. when I test on Windows XP, It has no error and exceptions. But I convert and test on Windows 7 with Multi-touch Library, My Browser occurred unhandled exception. Source: PresentationCore Message: An unspecified error occurred on the render thread. StackTrace: at System.Windows.Media.MediaContext.**NotifyPartitionIsZombie**(Int32 failureCode) at System.Windows.Media.MediaContext.NotifyChannelMessage() at System.Windows.Interop.HwndTarget.HandleMessage(Int32 msg, IntPtr wparam, IntPtr lparam) at System.Windows.Interop.HwndSource.HwndTargetFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled) at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled) at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o) at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter) at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler) InnerException: null I want to know where the bug occurred. That Trace Message are garbage information for me. I already googling to know that message, but i never found any information. How do I get exactly function where the bug occurred? please tell me something.

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• Simple App Engine Sessions Implementation

  - by raz0r

  Here is a very basic class for handling sessions on App Engine: """Lightweight implementation of cookie-based sessions for Google App Engine. Classes: Session """ import os import random import Cookie from google.appengine.api import memcache _COOKIE_NAME = 'app-sid' _COOKIE_PATH = '/' _SESSION_EXPIRE_TIME = 180 * 60 class Session(object): """Cookie-based session implementation using Memcached.""" def __init__(self): self.sid = None self.key = None self.session = None cookie_str = os.environ.get('HTTP_COOKIE', '') self.cookie = Cookie.SimpleCookie() self.cookie.load(cookie_str) if self.cookie.get(_COOKIE_NAME): self.sid = self.cookie[_COOKIE_NAME].value self.key = 'session-' + self.sid self.session = memcache.get(self.key) if self.session: self._update_memcache() else: self.sid = str(random.random())[5:] + str(random.random())[5:] self.key = 'session-' + self.sid self.session = dict() memcache.add(self.key, self.session, _SESSION_EXPIRE_TIME) self.cookie[_COOKIE_NAME] = self.sid self.cookie[_COOKIE_NAME]['path'] = _COOKIE_PATH print self.cookie def __len__(self): return len(self.session) def __getitem__(self, key): if key in self.session: return self.session[key] raise KeyError(str(key)) def __setitem__(self, key, value): self.session[key] = value self._update_memcache() def __delitem__(self, key): if key in self.session: del self.session[key] self._update_memcache() return None raise KeyError(str(key)) def __contains__(self, item): try: i = self.__getitem__(item) except KeyError: return False return True def _update_memcache(self): memcache.replace(self.key, self.session, _SESSION_EXPIRE_TIME) I would like some advices on how to improve the code for better security. Note: In the production version it will also save a copy of the session in the datastore. Note': I know there are much more complete implementations available online though I would like to learn more about this subject so please don't answer the question with "use that" or "use the other" library.

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• How to pass data to a C++0x lambda function that will run in a different thread?

  - by Dimitri C.

  In our company we've written a library function to call a function asynchronously in a separate thread. It works using a combination of inheritance and template magic. The client code looks as follows: DemoThread thread; std::string stringToPassByValue = "The string to pass by value"; AsyncCall(thread, &DemoThread::SomeFunction, stringToPassByValue); Since the introduction of lambda functions I'd like to use it in combination with lambda functions. I'd like to write the following client code: DemoThread thread; std::string stringToPassByValue = "The string to pass by value"; AsyncCall(thread, [=]() { const std::string someCopy = stringToPassByValue; }); Now, with the Visual C++ 2010 this code doesn't work. What happens is that the stringToPassByValue is not copied. Instead the "capture by value" feature passes the data by reference. The result is that if the function is executed after stringToPassByValue has gone out of scope, the application crashes as its destructor is called already. So I wonder: is it possible to pass data to a lambda function as a copy? Note: One possible solution would be to modify our framework to pass the data in the lambda parameter declaration list, as follows: DemoThread thread; std::string stringToPassByValue = "The string to pass by value"; AsyncCall(thread, [=](const std::string stringPassedByValue) { const std::string someCopy = stringPassedByValue; } , stringToPassByValue); However, this solution is so verbose that our original function pointer solution is both shorter and easier to read. Update: The full implementation of AsyncCall is too big to post here. In short, what happens is that the AsyncCall template function instantiates a template class holding the lambda function. This class is derived from a base class that contains a virtual Execute() function, and upon an AsyncCall() call, the function call class is put on a call queue. A different thread then executes the queued calls by calling the virtual Execute() function, which is polymorphically dispatched to the template class which then executes the lambda function.

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• Managing libraries and imports in a programming language

  - by sub

  I've created an interpreter for a stupid programming language in C++ and the whole core structure is finished (Tokenizer, Parser, Interpreter including Symbol tables, core functions, etc.). Now I have a problem with creating and managing the function libraries for this interpreter (I'll explain what I mean with that later) So currently my core function handler is horrible: // Simplified version myLangResult SystemFunction( name, argc, argv ) { if ( name == "print" ) { if( argc < 1 ) { Error('blah'); } cout << argv[ 0 ]; } else if ( name == "input" ) { if( argc < 1 ) { Error('blah'); } string res; getline( cin, res ); SetVariable( argv[ 0 ], res ); } else if ( name == "exit ) { exit( 0 ); } And now think of each else if being 10 times more complicated and there being 25 more system functions. Unmaintainable, feels horrible, is horrible. So I thought: How to create some sort of libraries that contain all the functions and if they are imported initialize themselves and add their functions to the symbol table of the running interpreter. However this is the point where I don't really know how to go on. What I wanted to achieve is that there is e.g.: an (extern?) string library for my language, e.g.: string, and it is imported from within a program in that language, example: import string myString = "abcde" print string.at( myString, 2 ) # output: c My problems: How to separate the function libs from the core interpreter and load them? How to get all their functions into a list and add it to the symbol table when needed? What I was thinking to do: At the start of the interpreter, as all libraries are compiled with it, every single function calls something like RegisterFunction( string namespace, myLangResult (*functionPtr) ); which adds itself to a list. When import X is then called from within the language, the list built with RegisterFunction is then added to the symbol table. Disadvantages that spring to mind: All libraries are directly in the interpreter core, size grows and it will definitely slow it down.

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• Fontforge finds no fonts

  - by user1858080

  I'm trying to make my c++ program detect installed fonts on my Win32 machine. I tried fontforge by taking the library from the GTK+ bundle. I use the following test code: #include<fontconfig.h> FcBool success = FcInit (); if ( !success ) { return false; } FcConfig *config = FcInitLoadConfigAndFonts (); if(!config) { return false; } FcChar8 *s, *file; FcPattern *p = FcPatternCreate(); FcObjectSet *os = FcObjectSetBuild (FC_FAMILY,NULL); FcFontSet *fs = FcFontList(config, p, os); LOG("Total fonts: %d\n", fs->nfont); for (int i=0; fs && i < fs->nfont; i++) { FcPattern *font = fs->fonts[i]; s = FcNameUnparse(font); LOG("Font: %s\n", s); free(s); if (FcPatternGetString(font, FC_FILE, 0, &file) == FcResultMatch) { LOG("Filename: %s\n", file); } } // destroy objects here ... Unfortunately this test application only prints: "Total fonts: 0" I know there are fonts installed on my machine and I know that Gimp2.0 detects them, so there must be somthing wrong with my test code. Does anyone have any idea? Besides linking the fontconfig-1.dll I did nothing special. I haven't created any config files or anything, because I couldn't read anywhere about having to do that. Please place any suggestions, thanks!

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• How to fix Java Image Fetcher error ?

  - by Frank

  My code looks like this : private static JFileChooser fc; if (fc==null) { fc=new JFileChooser(Image_Dir); fc.addChoosableFileFilter(new Image_Filter()); // Add a custom file filter and disable the default (Accept All) file filter. fc.setAcceptAllFileFilterUsed(false); fc.setAccessory(new Image_Preview(fc)); // Add the preview pane. } int returnVal=fc.showDialog(JFileChooser_For_Image.this,"Get Image"); // Show it. After I select an image from the panel, I got the following error message : Exception in thread "Image Fetcher 0" java.lang.UnsatisfiedLinkError: Native Library C:\Program Files (x86)\Java\jre6\bin\jpeg.dll already loaded in another classloader at java.lang.ClassLoader.loadLibrary0(Unknown Source) at java.lang.ClassLoader.loadLibrary(Unknown Source) at java.lang.Runtime.loadLibrary0(Unknown Source) at java.lang.System.loadLibrary(Unknown Source) at sun.security.action.LoadLibraryAction.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at sun.awt.image.JPEGImageDecoder.<clinit>(Unknown Source) at sun.awt.image.InputStreamImageSource.getDecoder(Unknown Source) at sun.awt.image.FileImageSource.getDecoder(Unknown Source) at sun.awt.image.InputStreamImageSource.doFetch(Unknown Source) at sun.awt.image.ImageFetcher.fetchloop(Unknown Source) at sun.awt.image.ImageFetcher.run(Unknown Source) When I run it from an executable Jar file, it works fine, but after I wrapped it into an exe file, I got the above error, why ? How to fix it ?

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• Is there a definitive reference document for Ruby syntax?

  - by JSW

  I'm searching for a definitive document on Ruby syntax. I know about the definitive documents for the core API and standard library, but what about the syntax itself? For instance, such a document should cover: reserved words, string literals syntax, naming rules for variables/classes/modules, all the conditional statements and their permutations, and so forth. I know there are many books and tutorials, yes, but every one of them is essentially a tutorial, each one having a range of different depth and focus. They will all, by necessity of brevity and narrative flow, omit certain details of the language that the author deems insignificant. For instance, did you know that you can use a case statement without an initial case value, and it will then execute the first true when clause? Any given Ruby book or tutorial may or may not cover that particular lesser-known functionality of the case syntax. It's not discussed in the section in "Programming Ruby" about case statements. But that is just one small example. So far the best documentation I've found is the rubyspec project, which appears to be an attempt to write a complete test suite for the language. That's not bad, but it's a bit hard to use from a practical standpoint as a developer working on my own projects. Am I just missing something or is there really no definitive readable document defining the whole of Ruby syntax?

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• Where does java.util.logging.Logger store their log

  - by Harry Pham

  This might be a stupid question but I am a bit lost with java Logger private static Logger logger = Logger.getLogger("order.web.OrderManager"); logger.info("Removed order " + id + "."); Where do I see the log? Also this quote from java.util.logging.Logger library: On each logging call the Logger initially performs a cheap check of the request level (e.g. SEVERE or FINE) against the effective log level of the logger. If the request level is lower than the log level, the logging call returns immediately. After passing this initial (cheap) test, the Logger will allocate a LogRecord to describe the logging message. It will then call a Filter (if present) to do a more detailed check on whether the record should be published. If that passes it will then publish the LogRecord to its output Handlers. Does this mean that if I have 3 request level log: logger.log(Level.FINE, "Something"); logger.log(Level.WARNING, "Something"); logger.log(Level.SEVERE, "Something"); And my log level is SEVERE, I can see all three logs, if my log level is WARNING, then I cant see SEVERE log, is that correct? And how do I set the log level?

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• Importing external .jar file to Android project

  - by robintw

  I've read various answers to similar questions on StackOverflow, so I apologise if I'm repeating another question, but I can't seem to get this to work. I have a standard java project in which I've written code to parse some BBC Radio XML data from the internet. The project is called BBCSchedules and the class I'm interested in is called BBCChannel. I'm now trying to use the BBCChannel class in an android application. How should I go about doing this? I've tried various things, following various bits of advice on the internet, and the place I've got to at the moment is compiling my BBCSchedules project to a .jar file, and importing that to the Android project using the Build Path/Library/Add External Jar option. However, Eclispe still doesn't recognise the BBCChannel class, and won't let me run the application because of this. I guess I've done something silly wrong, but what is it? Cheers, Robin UPDATE: I've tried the steps listed in http://stackoverflow.com/questions/1334802/how-can-i-use-external-jars-in-an-android-project and various other StackOverflow questions I can find that seem to be related to this, but absolutely nothing seems to work. Any other ideas? UPDATE: The discussions I've had with the author of the first answer below suggest that it is something to do with how I am using Eclipse to attach the .jar file. The project he sent me with the .jar file already attached didn't work. Any other ideas anyone?

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