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• Generate unique ID from multiple values with fault tolerance

  - by ojreadmore

  Given some values, I'd like to make a (pretty darn) unique result. $unique1 = generate(array('ab034', '981kja7261', '381jkfa0', 'vzcvqdx2993883i3ifja8', '0plnmjfys')); //now $unique1 == "sqef3452y"; I also need something that's pretty close to return the same result. In this case, 20% of the values is missing. $unique2 = generate(array('ab034', '981kja7261', '381jkfa0', 'vzcvqdx2993883i3ifja8')); //also $unique2 == "sqef3452y"; I'm not sure where to begin with such an algorithm but I have some assumptions. I assume that the more values given, the more accurate the resulting ID – in other words, using 20 values is better than 5. I also assume that a confidence factor can be calculated and adjusted. What would be nice to have is a weight factor where one can say 'value 1 is more important than value 3'. This would require a multidimensional array for input instead of one dimension. I just mashed on the keyboard for these values, but in practice they may be short or long alpha numeric values.

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• Java: Cleaing up connection reset (but not by peer).

  - by Zombies

  There seems to be some confusion as well contradicting statements on various SO answers: http://stackoverflow.com/questions/585599/whats-causing-my-java-net-socketexception-connection-reset . You can see here that the accepted answer states that the connecteion was closed by other side. But this is not true, closing a connection doesn't cause a connection reset. It is cauesed by "an underlying TCP/IP error." What I want to know is if a SocketException: Connection reset means really besides "unerlying TCP/IP Error." What really causes this? As I doubt it has anything to do with the connection being closed (since closing a connection isn't an exception worthy flag, and reading from a closed connection is, but that isn't an "underlying TCP/IP error." My hypothesis is this Connection reset is caused from a server's failure to acknowledge an ACK packet (either wholly or just improperly as per TCP/IP). And that a SocketTimeoutException is generated only when no data is generated to be read (since this is thrown during a read after a certain duration, and read is waiting for data, but is not concerned with ACK packets). In other words, read() throws SocketTimeoutException if it didn't read any bytes of actual data (DATA LAYER) in its allotted time.

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• Git repositories on shared hosting with ssh access - multiple users / one ssh account

  - by acp

  I'm part of a small team trying to start coding on a project. I've decided it's time to give git a chance (no more svn) and was trying to see if we could use our shared web hosting to deploy a "public" repository there so that we can easily push/pull to/from it and keep up-to-date with each others changes. The problem I'm having now is that we only have a single ssh account for that hosting. Having used svn in the past, I could enforce a svn username on a given pair of ssh keys, however I don't seem to be able to do something similar with git (in other words tie the ssh keypair to a specific dev). I don't mind everybody having read/write permissions everywhere, since anything that is private should stay on each others machine. Finally, solutions such as gitosis can not be used. I guess my question to you is how is accountability to git pushes given? Is it tied to the ssh account being used, or the email address given in git config? Can I create different ssh keys for every developer (for the same ssh account though), and just send them to the devs?

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• Is there any seriously good reason why a view can not completely manage itself?

  - by mystify

  Example: I have an warning triangle icon, which is a UIImageView subclass. That warning is blended in with an animation, pulses for 3 seconds and then fades out. it always has a parent view! it's always only used this way: alloc, init, add as subview, kick off animation, when done:remove from superview So I want this: [WarningIcon warningAtPosition:CGPointMake(50.0f, 100.0f) parentView:self]; BANG! That's it. Call and forget. The view adds itself as subview to the parent, then does it's animations. And when done, it cuts itself off from the branch with [self removeFromSupeview];. Now some nerd a year ago told me: "Never cut yourself off from your own branch". In other words: A view should never ever remove itself from superview if it's no more referenced anywhere. I want to get it, really. WHY? Think about this: The hard way, I would do actually the exact same thing. Create an instance and hang me in as delegate, kick off the animation, and when the warning icon is done animating, it calls me back "hey man i'm done, get rid of me!" - so my delegate method is called with an pointer to that instance, and I do the exact same thing: [thatWarningIcon removeFromSuperview]; - BANG. Now I'd really love to know why this sucks. Life would be so easy.

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• .NET security mechanism to restrict access between two Types in the same project?

  - by jdk

  Question: Is there a mechanism in the .NET Framework to hide one custom Type from another without using separate projects/assemblies? I'm using C# with ASP.NET in a Website project. Note: I'm not talking about access modifiers to hide members of a Type from another type - I mean to hide the Type itself. Background: I'm working in an ASP.NET Website project and the team has decided not to use separate project assemblies for different software layers. Therefore I'm looking for a way to have, for example, a DataAccess/ folder of which I disallow its classes to access other Types in the same ASP.NET Website project. In other words I want to fake the layers and have some kind of security mechanism around each layer to prevent it from accessing another. Obviously there's not a way to enforce this restriction using language-specific OO keywords so I am looking for something else, for example: maybe a permission framework or code access mechanism, maybe something that uses meta data like Attributes. Even something that restricts one namespace from accessing another. I'm unsure the final form it might take. If this were C++ I'd likely be using friend to make as solution, which doesn't translate to C# internal in this case although they're often compared. I don't really care whether the solution actually hides Types from each other or just makes them inaccessible; however I don't want to lock down one Type from all others, another reason access modifiers are not a solution. A runtime or design time answer will suffice. Looking for something easy to implement otherwise it's not worth the effort ...

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• Increasing understanding of validating a string with PHP string functions

  - by user1554264

  I've just started attempts to validate data in PHP and I'm trying to understand this concept better. I was expecting the string passed as an argument to the $data parameter for the test_input() function to be formatted by the following PHP functions. trim() to remove white space from the end of the string stripslashes() to return a string with backslashes stripped off htmlspecialchars() to convert special characters to HTML entities The issue is that the string that I am echoing at the end of the function is not being formatted in the way I desire at all. In fact it looks exactly the same when I run this code on my server - no white space removed, the backslash is not stripped and no special characters converted to HTML entities. My question is have I gone about this in the wrong approach? Should I be creating the variable called $santised_input on 3 separate lines with each of the functions trim(), stripslashes() and htmlspecialchars()? By my understanding surely I am overwriting the value of the $santised_input variable each time I recreate it on a new line of code. Therefore the trim() and stripslashes() string functions will never be executed. What I am trying to achieve is using the "$santised_input" variable to run all of these PHP string functions when the $data argument is passed to my test_input() function. In other words can these string functions be chained together so that I only need to create $santised_input once? <?php function test_input($data) { $santised_input = trim($data); $santised_input = stripslashes($data); $santised_input = htmlspecialchars($data); echo $santised_input; } test_input("%22%3E%3Cscript%3Ealert('hacked')%3C/script%3E\ "); //Does not output desired result "&quot;&gt;&lt;script&gt;alert('hacked')&lt;/script&gt;" ?>

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• Why use shorter VARCHAR(n) fields?

  - by chryss

  It is frequently advised to choose database field sizes to be as narrow as possible. I am wondering to what degree this applies to SQL Server 2005 VARCHAR columns: Storing 10-letter English words in a VARCHAR(255) field will not take up more storage than in a VARCHAR(10) field. Are there other reasons to restrict the size of VARCHAR fields to stick as closely as possible to the size of the data? I'm thinking of Performance: Is there an advantage to using a smaller n when selecting, filtering and sorting on the data? Memory, including on the application side (C++)? Style/validation: How important do you consider restricting colunm size to force non-sensical data imports to fail (such as 200-character surnames)? Anything else? Background: I help data integrators with the design of data flows into a database-backed system. They have to use an API that restricts their choice of data types. For character data, only VARCHAR(n) with n <= 255 is available; CHAR, NCHAR, NVARCHAR and TEXT are not. We're trying to lay down some "good practices" rules, and the question has come up if there is a real detriment to using VARCHAR(255) even for data where real maximum sizes will never exceed 30 bytes or so. Typical data volumes for one table are 1-10 Mio records with up to 150 attributes. Query performance (SELECT, with frequently extensive WHERE clauses) and application-side retrieval performance are paramount.

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• How to avoid the linebreak inside a word (Static Layout

  - by Addev

  I'm trying to make a text as big as I can making it fit a Rect. basically I use a StaticLayout for pre-calculate the text size and make it fit the Rect's height: // Since the width is fixed for the StaticLayout it should only fit the height while (currentHeight>Rect.getHeight()){ size-=2; } textPaint.setTextSize(size); The problem is that if the Rect is very high, the exit condition is reached but breaking the words (see the capture). Is there a way for avoid this? Goal: Actual: Current code: textSize=MAX_TEXT_SIZE do { if (textSize < mMinTextSize) { Log.i(TAG, "Min reached"); textSize = mMinTextSize; textPaint.setTextSize(textSize); fits = true; } else { textPaint.setTextSize(textSize); StaticLayout layout = new StaticLayout(text, textPaint, targetWidth, Alignment.ALIGN_NORMAL, 1.0, 0, true); layout.draw(canvas); float heightRatio= (float) layout.getHeight() / (float) targetHeight; boolean fitsHeight = heightRatio<= 1f; if (fitsHeight) { fits = true; } else { textSize -= 2; } } Log.i(TAG, "textSize=" + textSize + " fits=" + fits); } while (!fits); thanks

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• is there something equivalent to 'Address of' or offset operator in .net?

  - by Gio

  We have nested stuctures as such, used as an interface for some device drivers. On occasion we have to update individual elements. An 'address of' operator would be helpful, but an 'offset' function or operator is what I'm really looking for, but not sure how to go about it. In other words, how far is structureN.elementX away from the start of the structure in bytes? [StructLayout(LayoutKind.Sequential)] public struct s1 { UInt16 elem1; UInt16 elem2; UInt16 elem3; } [StructLayout(LayoutKind.Sequential)] public struct s2 { UInt16 elem1; UInt16 elem2; UInt16 elem3; } [StructLayout(LayoutKind.Sequential)] public struct driver { public S1 s1; public S2 s2; } For instance we need to send the device driver some data to update driver.s1.elem3, by way of providing an offset address, data block and length. We would update our local copy, then call the device api with the afore mentioned data. Not sure I have to do this with 'unsafe' method calls. Any help?

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• Writing a program which uses voice recogniton... where should I start?

  - by Katsideswide

  Hello! I'm a design student currently dabbling with Arduino code (based on c/c++) and flash AS3. What I want to do is to be able to write a program with a voice control input. So, program prompts user to spell a word. The user spells out the word. The program recognizes if this is right, adds one to a score if it's correct, and corrects the user if it's wrong. So I'm seeing a big list of words, each with an audio file of the word being read out, with the voice recognition part checking to see if the reply matches the input. Ideally i'd like to be able to interface this with an Arduino microcontroller so that a physical output with a motor could be achieved in reaction also. Thing is i'm not sure if I can make this program in flash, in Processing (associated with arduino) or if I need another CS3 program-making-program. I guess I need to download a good voice recognizing program, but how can I interface this with anything else? Also, I'm on a mac. (not sure if this makes a difference) I apologize for my cluelessness, any hints would be great! -Susan

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• Financial Market Developer dilemma...

  - by Sahat

  ...In the future I am planning to work in the financial sector as a programmer. I have a couple of options right now (1 or 2): Learn and master .NET since presumably that's widely used in that industry OR Learn the programming concepts, learn algorithms, learn a little bit of c,c++,c#,java,objective-c,sql,oracle,cobol - in other words learn the fundamental principles that tie all programming languages together without going too deep in any particular language. Someone has told me that most of the time as a programmer you won't be writing any code, but instead maintaing and existing code that people before you have built. Does that mean I don't really need to master any specific language and as long as I have general concepts it'll be good enough? If you or if you know someone who has worked in the financial industry as a software developer could you please share the experience and what is the daily routine consists of? Also what should I be learning right now while I am still young and in college? Do I have to thoroughly understand the market and the current economy? What about Oracle or SQL Databases - do I need to know them inside out as a programmer? Thanks if you have anything else to add that I have not mentioned then please do so! Thanks in advance!

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• Is it possible to create ostream object, which outputs to multiple destinations?

  - by fiktor

  In 0-th approximation I have a class class MyClass{ public: ... std::ostream & getOStream(){return f;} private: ofstream f; ... }; Which is used sometimes in the following way: MyClass myclass; myclass.getOStream()<<some<<information<<printed<<here; But now I want to change the class MyClass, so that information will be printed both to f and to std::out, i.e. I want the above line to be equivalent to myclass.f<<some<<information<<printed<<here; std::cout<<some<<information<<printed<<here; I don't know any good way to do that. Do you? Is there any standard solution (for example in stl or in boost)? P.S. I tried to search on this, but it seems that I don't know good keywords. Words multiple, output, ostream, C++, boost seem to be too general.

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• Javascript not reading value from hidden textBox - JQuery C#

  - by Paul van Valkenburgh

  I'm a non-specialist with JavaScript / JQuery and I'm having trouble figuring out why my script doesn't work. When my C# page loads, I have a hidden textBox txtHiddenKeywordArray which gets dynamically filled with comma separated values like... horse, buggy, track I'm trying to use the highlight functionality in jquery.highlight-3.js where I have a label text field that will contain and highlight the words in the keywords list. I'm using the script <script language="javascript" type="text/javascript"> var myString = document.getElementById('<%=txtHiddenKeywordArray.ClientID%>').val() myArray = myString.split(" "); $(document).ready(function () { for (i = 0; i < myArray.length; i++) $("p").highlight(myArray[i]) }); </script> Here is the textBox declaration : <asp:TextBox ID="txtHiddenKeywordArray" ClientIDMode="Static" runat="server" Visible="false"></asp:TextBox> It worked great when I hard coded the values of var myString. I've tried researching it and keep seeing the same example of the way I have it done. The page does use a MasterPage. Could this affect it? Any idea how I can get the script to see the values from the textbox? Do I need a RegisterStartUpScript or something? Thanks for any help you can provide.

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• How to implement a search page which shows results on the same page?

  - by Andrew

  I'm using ASP.NET MVC 2 for the first time on a project at work and am feeling like a bit of a noob. I have a page with a customer search control/partial view. The control is a textbox and a button. You enter a customer id into the textbox and hit search. The page then "refreshes" and shows the customer details on the same page. In other words, the customer details appear below the customer search control. This is so that if the customer isn't the right one, the user can search again without hitting back in the browser. Or, perhaps they mistyped the customer id and need to try again. I want the URL to look like this: /Customer/Search/1 Obviously, this follows the default route in the project. Now, if I type the URL above directly into my browser, it works fine. However, when I then use the search control on that page to search for say customer 2, the page refreshes with the correct customer details but the URL does not change! It stays as /Customer/Search/1 When I want it to be /Customer/Search/2 How can I get it to change to the correct URL? I am only using the default route in Global.asax. My Search method looks like this: <AcceptVerbs(HttpVerbs.Get)> _ Function Search(ByVal id As String) As ActionResult Dim customer As Customer = New CustomerRepository().GetById(id) Return View("SearchResult", customer) End Function

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• Dynamically assign class to paragraph

  - by user1684300

  How do you assign a class dynamically to a paragraph (via javascript/CSS) IF the paragraph contains the wording "Time Recorded:"? You'll notice that I have manually assigned the with class . However, I'd like to dynamically assign this class to any tag which contain the words "Time Recorded:". Please can you help ? Thank you. PLJ <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> <title>Untitled Document</title> <link href="css.css" rel="stylesheet" type="text/css" /> </head> <body> <script type="text/javascript"> if (document.all || document.getElementById){ //if IE4 or NS6+ document.write('<style type="text/css">') document.write('.dyncontent{display:none;}') document.write('</style>') } </script> <div class="right"> <ul> <li class="say agent public"> <p>Description line 1</p> <p class="dyncontent">Time Recorded: 5MIN(S)</p> <p>Another description line</p> </li> </ul> </div> </body> </html>

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• Getting the error "Missing $ inserted" in LaTeX

  - by Espenhh

  Hey, I try to write the following in latex: \begin{itemize} \item \textbf{insert(element|text)} inserts the element or text passed at the start of the selection. \item \textbf{insert_after(element|text)} inserts the element or text passed at the end of the selection. \item \textbf{replace(element|text)} replaces the selection with the passed text/element. \item \textbf{delete()} deletes the selected text. \item \textbf{annotate(name,value)} annotates the selected text with the passed name and value-pair. This can either be a hidden meta-data about the selection, or can alter the visible appearance. \item \textbf{clear_annotation()} removes any annotation for this specific selection. \item \textbf{update_element(value)} performs an update of the element at the selection with the passed value. \end{itemize} For some reason, I get a bunch of errors. I think there is something with the use of the word "insert". I get errors like "Missing $ inserted", so it seems like the parses tries to fix some "errors" on my parts. Do I need to escape words like "insert", how do I do that?

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• "pseudo-atomic" operations in C++

  - by dan

  So I'm aware that nothing is atomic in C++. But I'm trying to figure out if there are any "pseudo-atomic" assumptions I can make. The reason is that I want to avoid using mutexes in some simple situations where I only need very weak guarantees. 1) Suppose I have globally defined volatile bool b, which initially I set true. Then I launch a thread which executes a loop while(b) doSomething(); Meanwhile, in another thread, I execute b=true. Can I assume that the first thread will continue to execute? In other words, if b starts out as true, and the first thread checks the value of b at the same time as the second thread assigns b=true, can I assume that the first thread will read the value of b as true? Or is it possible that at some intermediate point of the assignment b=true, the value of b might be read as false? 2) Now suppose that b is initially false. Then the first thread executes bool b1=b; bool b2=b; if(b1 && !b2) bad(); while the second thread executes b=true. Can I assume that bad() never gets called? 3) What about an int or other builtin types: suppose I have volatile int i, which is initially (say) 7, and then I assign i=7. Can I assume that, at any time during this operation, from any thread, the value of i will be equal to 7? 4) I have volatile int i=7, and then I execute i++ from some thread, and all other threads only read the value of i. Can I assume that i never has any value, in any thread, except for either 7 or 8? 5) I have volatile int i, from one thread I execute i=7, and from another I execute i=8. Afterwards, is i guaranteed to be either 7 or 8 (or whatever two values I have chosen to assign)?

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• Is CDS a valid analogy for pointers? [closed]

  - by Flinkman

  So.. bear with me. I just found an analogy to c++ pointers and CDS. This clip describes CDS(Credit Default Swaps). http://www.youtube.com/watch?v=KPNdYtrlgaU#t=120s "Here we know we have an instrument of a particular financial instrument that is demonstrably dangerous, it creates long chains of risk which are vulnerable to the failure of individual trader or market partipants, in that chain and these instruments in an affect permit the creation of vicious spirals. In which the CDS price interact with the bound price, the market price and you can have a downward spiral." What my ears are telling me: "Don't create dependences that will create long chains of crashing systems." Update: Trying to clarify with something that is closer to the readers. If I change the words: instrument = construct financial = language trader = object market partipants = c structs CDS price = uptime bound price = outcome market price = ROI(return on incestment) The quote become more understandable. Look: "Here we know we have construct of a particular language construct that is demonstrably dangerous, it creates long chains of risk which are vulnerable to the failure of individual object or structs in that chain and these system in an affect permit the creation of vicious spirals. In which the uptime interact with the outcome, the ROI and you can have a downward spiral."

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• regexp to match string with (comma-separated) number at start and to split into number and rest?

  - by mix

  Given a string such as: 23,234,456 first second third How can I split string this into two parts, where part 1 contains the number at the beginning and part 2 contains the rest---but only if the string STARTS with a number, and the number can be comma-separated or not? In other words, I want two results: 23,234,456 and first second third. If there's a number in that string that isn't part of the first number then it should be in the second result. My best stab at this so far, to grab the number at the beginning, is something like this: ^[0-9]+(,[0-9]{3})* Which seems to grab a comma-separated or non-comma-separated number that starts the line. However, when I run this in the Javascript console I get not only the full number, but also a match on just the last 3 digits with their preceeding ,. (e.g. 23,234,456 and ,456). As for getting the rest into another var I'm having trouble. I tried working with \b, etc., but I think I must be missing something fundamental about grabbing the rest of the line. I'm doing this in Javascript in case it matters. More examples of what to match and what not to match. 2 one two three should return 2 and one two three 2345 one two three should return 2345 and one two three 2 one 2 three should return 2 and one 2 three 2,234 one two 3,000 should return 2,234 and one two 3,000 The space between parts 1 and two could be included in the beginning of part 2.

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• JavaScript array random index insertion and deletion

  - by Tomi

  I'm inserting some items into array with randomly created indexes, for example like this: var myArray = new Array(); myArray[123] = "foo"; myArray[456] = "bar"; myArray[789] = "baz"; ... In other words array indexes do not start with zero and there will be "numeric gaps" between them. My questions are: Will these numeric gaps be somehow allocated (and therefore take some memory) even when they do not have assigned values? When I delete myArray[456] from upper example, would items below this item be relocated? EDIT: Regarding my question/concern about relocation of items after insertion/deletion - I want to know what happens with the memory and not indexes. More information from wikipedia article: Linked lists have several advantages over dynamic arrays. Insertion of an element at a specific point of a list is a constant-time operation, whereas insertion in a dynamic array at random locations will require moving half of the elements on average, and all the elements in the worst case. While one can "delete" an element from an array in constant time by somehow marking its slot as "vacant", this causes fragmentation that impedes the performance of iteration.

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• Email server; Is this method spam-safe?

  - by Camran

  I have a classifieds website, and on each classified there is a tip-form where users may tip a friend about the classified. The tip-forms' action is set to a php-page, which mails the email after sanitizing etc... I have to filter away spam etc so that my email-server don't get blacklisted or anything... I have my own server (VPS, Linux) and have thought about a solution... How does this sound to you: 1- Install a mail-server 2- Configure Firewall to ONLY allow connections to the mail-server from my website 3- Configure the mail-server so that a maximum of 'x' emails may be sent every 5 minutes or so 4- Create a php filter before sending the mail, which checks for 'bad' words. 5- If necessary, as last resort, ask the user a question (ex 5+5) before submitting form I would rather preferr if I didn't have to implement the 5th implementation above... What do you think? Also, another q I have that you may answer is: If an email-server gets blacklisted, is there any way to un-blacklist it? Or whats the solution if this happens? Thanks

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• Linux: Find all symlinks of a given 'original' file? (reverse 'readlink')

  - by sdaau

  Hi all, Consider the following command line snippet: $ cd /tmp/ $ mkdir dirA $ mkdir dirB $ echo "the contents of the 'original' file" > orig.file $ ls -la orig.file -rw-r--r-- 1 $USER $USER 36 2010-12-26 00:57 orig.file # create symlinks in dirA and dirB that point to /tmp/orig.file: $ ln -s $(pwd)/orig.file $(pwd)/dirA/ $ ln -s $(pwd)/orig.file $(pwd)/dirB/lorig.file $ ls -la dirA/ dirB/ dirA/: total 44 drwxr-xr-x 2 $USER $USER 4096 2010-12-26 00:57 . drwxrwxrwt 20 root root 36864 2010-12-26 00:57 .. lrwxrwxrwx 1 $USER $USER 14 2010-12-26 00:57 orig.file -> /tmp/orig.file dirB/: total 44 drwxr-xr-x 2 $USER $USER 4096 2010-12-26 00:58 . drwxrwxrwt 20 root root 36864 2010-12-26 00:57 .. lrwxrwxrwx 1 $USER $USER 14 2010-12-26 00:58 lorig.file -> /tmp/orig.file At this point, I can use readling to see what is the 'original' (well, I guess the usual term here is either 'target' or 'source', but those in my mind can be opposite concepts as well, so I'll just call it 'original') file of the symlinks, i.e. $ readlink -f dirA/orig.file /tmp/orig.file $ readlink -f dirB/lorig.file /tmp/orig.file ... However, what I'd like to know is - is there a command I could run on the 'original' file, and find all the symlinks that point to it? In other words, something like (pseudo): $ getsymlinks /tmp/orig.file /tmp/dirA/orig.file /tmp/dirB/lorig.file Thanks in advance for any comments, Cheers!

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• Overhead of calling tiny functions from a tight inner loop? [C++]

  - by John

  Say you see a loop like this one: for(int i=0; i<thing.getParent().getObjectModel().getElements(SOME_TYPE).count(); ++i) { thing.getData().insert( thing.GetData().Count(), thing.getParent().getObjectModel().getElements(SOME_TYPE)[i].getName() ); } if this was Java I'd probably not think twice. But in performance-critical sections of C++, it makes me want to tinker with it... however I don't know if the compiler is smart enough to make it futile. This is a made up example but all it's doing is inserting strings into a container. Please don't assume any of these are STL types, think in general terms about the following: Is having a messy condition in the for loop going to get evaluated each time, or only once? If those get methods are simply returning references to member variables on the objects, will they be inlined away? Would you expect custom [] operators to get optimized at all? In other words is it worth the time (in performance only, not readability) to convert it to something like: ElementContainer &source = thing.getParent().getObjectModel().getElements(SOME_TYPE); int num = source.count(); Store &destination = thing.getData(); for(int i=0;i<num;++i) { destination.insert(thing.GetData().Count(), source[i].getName(); } Remember, this is a tight loop, called millions of times a second. What I wonder is if all this will shave a couple of cycles per loop or something more substantial? Yes I know the quote about "premature optimisation". And I know that profiling is important. But this is a more general question about modern compilers, Visual Studio in particular.

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• error in a c code while trying to remove whitespace

  - by mekasperasky

  this code is the base of lexer , and it does the basic operation of removing the whitespaces from a source file and rewrites it into another file with each word in separate lines . But i am not able to understand why the file lext.txt not getting updated? #include<stdio.h> /* this is a lexer which recognizes constants , variables ,symbols, identifiers , functions , comments and also header files . It stores the lexemes in 3 different files . One file contains all the headers and the comments . Another file will contain all the variables , another will contain all the symbols. */ int main() { int i; char a,b[20],c; FILE *fp1,*fp2; fp1=fopen("source.txt","r"); //the source file is opened in read only mode which will passed through the lexer fp2=fopen("lext.txt","w"); //now lets remove all the white spaces and store the rest of the words in a file if(fp1==NULL) { perror("failed to open source.txt"); //return EXIT_FAILURE; } i=0; while(!feof(fp1)) { a=fgetc(fp1); if(a!="") { b[i]=a; printf("hello"); } else { b[i]='\0'; fprintf(fp2, "%.20s\n", b); i=0; continue; } i=i+1; /*Switch(a) { case EOF :return eof; case '+':sym=sym+1; case '-':sym=sym+1; case '*':sym=sym+1; case '/':sym=sym+1; case '%':sym=sym+1; case ' */ } return 0; }

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• How to synchronize two (or n) replication processes for SQL Server databases?

  - by Yauheni Sivukha

  There are two master databases and two read-only copies updated by standard transactional replication. It is needed to map some entity from both read-only databases, lets say that A databases contains orders and B databases contains lines. The problem is that replication to one database can lag behind replication of second database, and at the moment of mapping R-databases will have inconsistent data. For example. We stored 2 orders with lines at 19:00 and 19:03. Mapping process started at 19:05, but to the moment of mapping A database replication processed all changes up to 19:03, but B database replication processed only changes up to 19:00. After mapping we will have order entity with order as of 19:03 and lines as of 19:00. The troubles are guaranteed:) In my particular case both databases have temporal model, so it is possible to fetch data for every time slice, but the problem is to identify time of latest replication. Question: How to synchronize replication processes for several databases to avoid situation described above? Or, in other words, how to compare last time of replication in each database? UPD: The only way I see to synchronize is to continuously write timestamps into service tables in each database and to check these timestamps on replicated servers. Is that acceptable solution?

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