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  • Strange C++ thread function invocation

    - by Tony
    I have the following: class DThread { virtual void run()=0; _beginthreadex(NULL,0,tfunc,this,0,&m_UIThreadID); // class itself being passed as param to thread function... static unsigned int __stdcall tfunc(void* thisptr) { static_cast<DThread*>(thisptr)->run(); return 0; } //other stuff } The run function is implemented in a derived class. Why is the function that's being called in the thread being called through a cast this pointer? Is this good practise? Can't it just be called directly? The actual function needing to run is in the derived class. My question is

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  • user buffer after doing 'write' to file opened with O_DIRECT

    - by user1868481
    I'm using the O_DIRECT flag to write to the disk directly from the user buffer. But as far as I understand, Linux doesn't guarantee that after this call, the data is written. It just writes directly from the user buffer to the physical device using DMA or anything else... Therefore, I don't understand if I can write to the user buffer after the call to 'write' function. I'm sure that example code will help to understand my question: char *user_buff = malloc(...); /* assume it is aligned as needed */ fd = open(..., O_DIRECT); write(fd, ...) memset(user_buff, 0, ...) Is the last line (memset) legal? Is writing to the user buffer valid that is maybe used by DMA to transfer data to the device?

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  • Database table schema design - varchar(n). Suitable choice of N

    - by morpheous
    Coming from a C background, I may be getting too anal about this and worrying unnecessarily about bits and bytes here. Still, I cant help thinking how the data is actually stored and that if I choose an N which is easily factorizable into a power of 2, the database will be more effecient in how it packs data etc. Using this "logic", I have a string field in a table which is a variable length up to 21 chars. I am tempted to use 32 instead of 21, for the reason given above - however now I am thinking that I am wasting disk space because there will be space allocated for 11 extra chars that are guaranteed to be never used. Since I envisage storing several tens of thousands of rows a day, it all adds up. Question: Mindful of all of the above, Should I declare varchar(21) or varchar(32) and why?

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  • Size of a class with 'this' pointer

    - by psvaibhav
    The size of a class with no data members is returned as 1 byte, even though there is an implicit 'this' pointer declared. Shouldn't the size returned be 4 bytes(on a 32 bit machine)? I came across articles which indicated that 'this' pointer is not counted for calculating the size of the object. But I am unable to understand the reason for this. Also, if any member function is declared virtual, the size of the class is now returned as 4 bytes. This means that the vptr is counted for calculating the size of the object. Why is the vptr considered and 'this' pointer ignored for calculating the size of object?

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  • Anyway to improve my gzip PHP method?

    - by Joe
    I Gzip my pages currently like so: <?php ob_start("ob_gzhandler"); //my page content ob_flush(); ?> However, I read a comment somewhere, earlier on, that this method uses a lot of memory, and I know that my website has been using a lot of memory on my virtual private server, so I thought it would be nice if I knew a way to reduce memory usage. I tested my site with an online gzip tester which says my websites are sending gzipped pages, so my gzip method works, but the main obviously I'm looking for a less memory intensive option, if any. I appreciate all suggestions. :) Oh and merry christmas ;P

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  • How to track when my application has unexpectedly shut down?

    - by Vilx-
    I'm writing an application whose purpose involves a lot of logging of different events. Among those I would also like to have an event that the application was shut down - even if unexpectedly like because of a power loss. Naturally, when the power goes out I don't get a chance to write anything anywhere. So my idea was to continuously write a timestamp in some known location (say, once per minute), and when the application was next run, it could determine the approximate time of the unexpected shutdown. A precision of 1 minute would be acceptable for me. However I'm worried that caching at the OS and disk level might interfere with this approach. Is there a better way or if not - how to make sure that the data I just wrote is REALLY written out to the physical medium? Added: Oh, almost forgot the buzzword line: Windows XP and above; .NET 3.5; C#.

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  • Implement abstract class as a local class? pros and cons

    - by sinec
    Hi, for some reason I'm thinking on implementing interface within a some function(method) as local class. Consider following: class A{ public: virtual void MethodToOverride() = 0; }; A * GetPtrToAImplementation(){ class B : public A { public: B(){} ~B(){} void MethodToOverride() { //do something } }; return static_cast<A *>(new B()); } int _tmain(int argc, _TCHAR* argv[]) { A * aInst = GetPtrToAImplementation(); aInst->MethodToOverride(); delete aInst; return 0; } the reason why I'm doing this are: I'm lazy to implement class (B) in separate files MethodToOverride just delegates call to other class Class B shouldn't be visible to other users no need to worry about deleting aInst since smart pointers are used in real implementation So my question is if I'm doing this right? Thanks in advance!

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  • Compare images to find differences

    - by _simon_
    Task: I have a camera mounted on the end of our assembly line, which captures images of produced items. Let's for example say, that we produce tickets (with some text and pictures on them). So every produced ticket is photographed and saved to disk as image. Now I would like to check these saved images for anomalies (i.e. compare them to an image (a template), which is OK). So if there is a problem with a ticket on our assembly line (missing picture, a stain,...), my application should find it (because its image differs too much from my template). Question: What is the easiest way to compare pictures and find differences between them? Do I need to write my own methods, or can I use existing ones? It would be great if I just set a tolerance value (i.e. images can differ for 1%), put both images in a function and get a return value of true or false :) Tools: C# or VB.NET, Emgu.CV (.NET wrapper for OpenCV) or something similar

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  • Recommand a Perl module to persist a large object for re-use between runs?

    - by Alnitak
    I've got a large XML file, which takes 40+ seconds to parse with XML::Simple. I'd like to be able to cache the resulting parsed object so that on the next run I can just retrieve the parsed object and not reparse the whole file. I've looked at using Data::Dumper but the documentation is a bit lacking on how to store and retrieve its output from disk files. Other classes I've looked at (e.g. Cache::Cache) appear designed for storage of many small objects, not a single large one. Can anyone recommend a module designed for this?

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  • jQuery AJAX & an ASP.NET web service works locally but not remotely

    - by Alex
    Interesting one here. I have an ASP.NET 1.1 project that contains a web service in it. I'm using jQuery's AJAX functionality to call some services from the client. This is what my code looks like: $.ajax({ type: "POST", url: 'foo.asmx/functionName', data: 'foo1=' + foo1 + '&foo2=' + foo2, dataType: "xml", success: function(xml) { //do something with my xml data }, error: function(request, error){ //handle my error } }); This works great when I run the site from my IDE on localhost. However, when I deploy this site to any other server I get a parsererror error from jQuery. It does not appear to even call my service as I dropped in some code to write a log file to disk and it's not making it there. The same exact XML should be returned from both my localhost and the server I deployed to. Any ideas?

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  • JBoss 4.0.5 startup takes 15 minutes deploying a single war file

    - by dkblinux98
    This instance of JBoss deploys several war files. The rest of the JBoss startup takes about 5 minutes or less. But when it gets to one particular war file, startup just hangs with no further output to the jboss log. It waits there for about 15 minutes and then suddenly the war starts deploying. The rest of the JBoss startup is then fine. What I want to know is what steps do you recommend I take to diagnose the cause of this condition? It is not possible to upgrade this site to a newer version of JBoss nor java (currently 1.5.0.7). It is running on 32-bit CentOS 5.3 Linux on 3 xen-based virtual servers in a load balanced configuration. The code is common to all three servers via an nfs share. This same issue was seen, however, when the 3 servers were physical and the code was local to each server. The servers are each 2 cpu, 4GB RAM servers.

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  • Is it possible to exclude folders from a web application project in vs 2010?

    - by JL
    I had previously asked this question. At the time I was working with VS 2008. To restate the question. I have a web application that generates 1000's of small xml files in a certain directory. I would like to exclude this directory from the web application project in visual studio 2010. With vs 2008 it was not possible. Has anything changed? Besides the general wait for VS to iterate through this directory and add an item in the solution explorer for each file, it also strains my system resources, so I would like to exclude it from the project, but the dir and files need to physically exist on disk, because they are part of the application. Any OOB VS 2010 solutions, or any good workarounds? Thanks Update: This also sums up the issue nicely http://forums.asp.net/t/1179077.aspx

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  • Create object of unknown class (two inherited classes)

    - by Paul
    I've got the following classes: class A { void commonFunction() = 0; } class Aa: public A { //Some stuff... } class Ab: public A { //Some stuff... } Depending on user input I want to create an object of either Aa or Ab. My imidiate thought was this: A object; if (/*Test*/) { Aa object; } else { Ab object; } But the compiler gives me: error: cannot declare variable ‘object’ to be of abstract type ‘A’ because the following virtual functions are pure within ‘A’: //The functions... Is there a good way to solve this?

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  • Forms Authentication Across Applications Stopped Working

    - by colleski
    Hi, I have a .net 1.1 ASP application (domain.com) which has a .net 2 virtual directory (domain.com/v2) beneath it, both applications run within their own app pool on the same machine running IIS 6. The web.config files for both apps are setup for Forms Authentication as described here - http://msdn.microsoft.com/en-us/library/eb0zx8fc(v=VS.80).aspx. Users would be directed to the domain.com/v2/login.aspx page which would authenticate for both applications, this configuration has been working fine for the last few years until installing one of the recent Windows 2003 security updates today. Now after authenticating under /v2 users keep getting redirected back to domain.com/v2/Login.aspx as domain.com doesnt see them as authenticated anymore. Any ideas as to which security update would have caused this and if its possible to rollback? I've looked at a few suggestions on this (e.g. Cross app on subdomain form authentication not working) and other sites but no luck so far Any help would be appreciated. Thanks

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  • Is it possible to remove folders from a web application build process in vs 2010?

    - by JL
    I had previously asked this question. At the time I was working with VS 2008. To restate the question. I have a web application that generates 1000's of small xml files in a certain directory. I would like to exclude this directory from the build process in visual studio 2010. With vs 2008 it was not possible. Has anything changed? Besides the general wait for VS to iterate through this directory with each build, it also strains my system resources, so I would like to exclude it from the project, but the dir and files need to physically exist on disk, because they are part of the application. Any OOB VS 2010 solutions, or any good workarounds? Thanks

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  • Have a workaround for the 1,000 file limit in a directory on windows mobile 5?

    - by nateday76
    I need to download more than 1,000 files into a windows mobile 5 directory located on the storage card. If i copy the files onto the storage card via my desktop there is no problem. But when i try to download the files from the handheld device I get a disk full error, even though there is plenty of room due to the 1,000 file limit. Has anyone run into this and found a workaround? I'm going to try zipping all of the files then decompressing on the device but not sure that this will work.

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  • Execute a batch script from Firefox

    - by danilo
    I have written an intranet application from which you can directly connect to a virtual machine by clicking on a RDP-button. The click calls a .bat file, which opens the connection. With IE, this is no problem, as you can choose to directly execute the batch file. But with Firefox, I can only download the script, and have to start it manually afterwards. Is there a way to trust the intranet domain (about:config?) so Firefox allows it to execute scripts directly? Or is there an even better (easier) way to start an RDP connection from Firefox?

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  • how to render custom columns with a GenericTreeModel

    - by Giorgio Gelardi
    I have to display some data in a treeview. The "real" data model is huge and I cannot copy all the stuff in a TreeStore, so I guess I should use a GenericTreeModel to act like a virtual treeview. Btw the first column is the classic icon+text style and I think I should declare a column with a CellRendererPixbuf (faq sample), but I'm not sure what the model methods on_get_n_columns() and on_get_value() should return. It's both a Pixbuf and a string value for the same column. Any help will be appreciated.

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  • Searching for URL's Relative to Site Root in Javascript Source

    - by James
    Hi, I am working on a web site with several other developers and we have had problems where people commit JavaScript code with AJAX calls that use URL's relative to the site root. An example would be /Home/Index which will not work if the site is hosted in a virtual directory. To get round the problem we use a $.url() method to convert it to a full path, e.g. $("#container").load($.url("/Home/Index")) I am trying to write a unit test that will search each JavaScript file and find places where the $.url method is not being used. The only problem is that I cannot seem to write a regex expression to do this. I have tried the following: (?!\$\.url\()"(/\w*)+" But this does not work. I cannot find a way to say that I don't want the $.url in front. Does anyone know if this is possible? Note that I need regular expressions that are compatible with .NET Thanks.

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  • PHP editors for Ubuntu

    - by mepo
    What are the Light weight PHP editors available for ubuntu? And is there a ubuntu version of the Notepad++ editor. For those who haven't used Notepad++, do not confuse it with Notepad.exe. Notepad.exe is the lightweight Windows editor by Microsoft. Notepad++ is an Open Source programmer's text editor for Windows based on SciTE. It has syntax highlighting, code collapsing, language recognition, macro recording, regular expression search and replace across line breaks and in files on disk, copy filenames and paths to clipboard, and many other advance text editing tools. Only the more full-featured editors for Linux would be likely to be suitable replacements for Notepad++. Thanks

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  • Rewrite Registry File in Windows

    - by Vulcan Eager
    I have been trying to find a way to "defragment" the registry on my Windows machine. Firstly, does this make sense? Any benefits in doing this? (Not much love on superuser.com) Secondly, I am looking for a way to rewrite the registry using C/C++ with Windows API. Is there a way to read the registry and write it to a new file getting rid of unused bytes along the way? (I might have to write the new file and then boot into another OS/disk before I can overwrite the original... but I am willing to take that risk.)

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  • Sharepoint always down on the weekend?

    - by TheGambler
    For some reason, our sharepoint site always goes down on Saturday. It's the stangest thing and I can't figure out why. I'm a total noob at sharepoint and have been thrown into being the go to guy for sharepoint with my current employer. I've tried bouncing IIS on Fridays to see if there is anything I can do before hand. Is there anything that might be scheduled that I may not know about that would cause sharepoint to go down? Remember I'm a total noob as sharepoint. Thanks to all that reply. Edit: Also this our front-end and database instances are on virtual servers.

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  • Creating AVI files in OpenCV

    - by user80003
    Hello. I have been trying to create an application using OpenCV and Visual Studio 2008, to capture images from a webcam, apply a filter to them, and then write them to an AVI file. Everything works, except creating the AVI file. The problem is that it works on my computer, but it doesn't work on my colleague's computer. The reason for that (I think) is that he does not have the necessary video encoders for OpenCV to use. The cvCreateVideoWriter function does not return NULL, but I end up with a 0kb file on the disk.

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  • Uploading files wont work on production server

    - by Camran
    I have a php script which uploads images to a temporary folder on the server. This works on my local computer with the local (virtual) server. (wampserver). However, on the production server (linux) I cant get it working. Everything is loading as it should, except for that the file doesn't show up on the server. My Q is, is there anything I should think about when moving to a production server with uploading images or files? I have set permissions on the folder where the images are supposed to go to 777 and also the php-code which uploads them to 777. Thanks

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  • How to return data structure from stored procedure

    - by rodnower
    Hello, I have C# application that retrieve data from AQ with some oracle stored procedure, that stored in package. The scheme is: C# code - Stored Procedure in Package - AQ Inside of this stored procedure I use DBMS_AQ for dequeue the data to some object of some type. Now I have this object. My question is how I return it? Previously I: Created some virtual table, Make EXTEND() to table Inserted the data from object to table, Perform select on the table, And return sys_refcursor. In side of C# I filled DataSet with help of OracleDataAdapter.Fill() After that I upgraded it to return data fields during OUT parameters. But now I have much fields, and I may not to create so much OUT parameters... What the best way to do this? Thank you for ahead.

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