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• What languages should a microISV use to write commercial software?

  - by Wal

  I've been writing software in Java for many years now, but it was always for internal applications that would be deployed to a server. I'd like to get into writing desktop applications now but I don't know where to start. I've written a few Java/Swing applications but again they were for internal use. My understanding is that Java and other semi-compiled and interpreted languages are too easy to reverse engineer, making them unsuitable for commercial software. I am aware that there are compilers for Java and some other interpreted language, but I've also heard that they are pricey and/or unreliable. Assuming I start a microISV and wish to develop and sell applications to a broad audience, what's my best bet? I would prefer something that can be written close to once, and compiled for different operating systems but I am not opposed to .NET and a Windows-only audience if other languages would compromise the experience (installation ease & user experience) in Windows. My only issue there is that I don't have a large starting budget and paying out the wazoo for the required development tools is not really in the cards.

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• Why isn't !locks working for me?

  - by jeffamaphone

  I'm using windbg (the latest available from the MSDN download page). I'm trying to debug a deadlock in my app, and !locks would be very useful. However, it's not working: 0:023> !locks NTSDEXTS: Unable to resolve ntdll!RTL_CRITICAL_SECTION_DEBUG type NTSDEXTS: Please check your symbols I don't know why it's upset. I've got symbols properly loaded: 0:023> .sympath Symbol search path is: srv* Expanded Symbol search path is: cache*c:\debuggers\sym;SRV*http://msdl.microsoft.com/download/symbols And NTSD agrees: 0:023> lmv m ntdll start end module name 777b0000 77930000 ntdll (pdb symbols) c:\debuggers\sym\wntdll.pdb\E9D10FA3EB884A23A5854E04FB7E2F0C2\wntdll.pdb Loaded symbol image file: C:\Windows\SysWOW64\ntdll.dll Image path: ntdll.dll Image name: ntdll.dll Timestamp: Mon Jul 13 18:11:23 2009 (4A5BDB3B) CheckSum: 00148A78 ImageSize: 00180000 File version: 6.1.7600.16385 Product version: 6.1.7600.16385 File flags: 0 (Mask 3F) File OS: 40004 NT Win32 File type: 2.0 Dll File date: 00000000.00000000 Translations: 0409.04b0 CompanyName: Microsoft Corporation ProductName: Microsoft® Windows® Operating System InternalName: ntdll.dll OriginalFilename: ntdll.dll ProductVersion: 6.1.7600.16385 FileVersion: 6.1.7600.16385 (win7_rtm.090713-1255) FileDescription: NT Layer DLL LegalCopyright: © Microsoft Corporation. All rights reserved. And the stack looks good: 0:036> k ChildEBP RetAddr 1506fdd8 7784f546 ntdll!DbgBreakPoint 1506fe08 75bf3677 ntdll!DbgUiRemoteBreakin+0x3c 1506fe14 777e9d72 kernel32!BaseThreadInitThunk+0xe 1506fe54 777e9d45 ntdll!__RtlUserThreadStart+0x70 1506fe6c 00000000 ntdll!_RtlUserThreadStart+0x1b Any help is appreciated.

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• Pass checkbox values with Jquery to PHP and display result in div

  - by user1343955

  I want to filter realtime results with jQuery (just like on this site http://shop.www.hi.nl/hi/mcsmambo.p?M5NextUrl=RSRCH). So when someones checks a checkbox the results should update realtime (in a div). Now I'm a newbie with jQuery and I've tried lots of examples but I can't get it to work. Here's my code, could anyone tell what I'm doing wrong? Thank you very much! HTML <div id="c_b"> Kleur:<br /> <input type="checkbox" name="kleur[1]" value="Blauw"> Blauw <br /> <input type="checkbox" name="kleur[2]" value="Wit"> Wit <br /> <input type="checkbox" name="kleur[3]" value="Zwart"> Zwart <br /> <br /> Operating System:<br /> <input type="checkbox" name="os[1]" value="Android"> Android <br /> <input type="checkbox" name="os[2]" value="Apple iOS"> Apple iOS <br /> </div> <div id="myResponse">Here should be the result</div> jQuery function updateTextArea() { var allVals = []; $('#c_b :checked').each(function() { allVals.push($(this).val()); }); var dataString = $(allVals).serialize(); $.ajax({ type:'POST', url:'/wp-content/themes/u-design/filteropties.php', data: dataString, success: function(data){ $('#myResponse').html(data); } }); } $(document).ready(function() { $('#c_b input').click(updateTextArea); updateTextArea(); }); PHP //Just to see if the var passing works echo var_export($_POST);

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• Scheme: what are the benefits of letrec?

  - by Ixmatus

  While reading "The Seasoned Schemer" I've begun to learn about letrec. I understand what it does (can be duplicated with a Y-Combinator) but the book is using it in lieu of recurring on the already defined function operating on arguments that remain static. An example of an old function using the defined function recurring on itself (nothing special): (define (substitute new old lat) (cond ((null? l) '()) ((eq? (car l) old) (cons new (substitute new old (cdr l)))) (else (cons (car l) (substitute new old (cdr l)))))) Now for an example of that same function but using letrec: (define (substitute new old lat) (letrec ((replace (lambda (l) (cond ((null? l) '()) ((eq? (car l) old) (cons new (replace (cdr l)))) (else (cons (car l) (replace (cdr l)))))))) (replace lat))) Aside from being slightly longer and more difficult to read I don't know why they are rewriting functions in the book to use letrec. Is there a speed enhancement when recurring over a static variable this way because you don't keep passing it?? Is this standard practice for functions with arguments that remain static but one argument that is reduced (such as recurring down the elements of a list)? Some input from more experienced Schemers/LISPers would help!

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• Why this code generates different numbers?

  - by frbry

  Hello, I have this function that creates a unique number for hard-disk and CPU combination. DWORD hw_hash() { char drv[4]; char szNameBuffer[256]; DWORD dwHddUnique; DWORD dwProcessorUnique; DWORD dwUniqueKey; char *sysDrive = getenv ("SystemDrive"); strcpy(drv, sysDrive); drv[2] = '\\'; drv[3] = 0; GetVolumeInformation(drv, szNameBuffer, 256, &dwHddUnique, NULL, NULL, NULL, NULL); SYSTEM_INFO si; GetSystemInfo(&si); dwProcessorUnique = si.dwProcessorType + si.wProcessorArchitecture + si.wProcessorRevision; dwUniqueKey = dwProcessorUnique + dwHddUnique; return dwUniqueKey; } It returns different numbers if I format my hard-disk and install a new Windows. Any ideas, why? Thank you. Edit: OK, Got it: This function returns the volume serial number that the operating system assigns when a hard disk is formatted. To programmatically obtain the hard disk's serial number that the manufacturer assigns, use the Windows Management Instrumentation (WMI) Win32_PhysicalMedia property SerialNumber. I should do more research before posting my problems online. Sorry to bother you, let's keep this here in case anybody else can need it.

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• Advantages of Using Linux as primary developer desktop

  - by Nick N

  I want to get some input on some of the advantages of why developers should and need to use Linux as their primary development desktop on a daily basic as opposed to using Windows. This is particulary helpful when your Dev, QA, and Production environments are Linux. The current analogy that I keep coming back to is. If I build my demo car as a Ford Escort, but my project car is a Ford Mustang, it doesn't make sense at all. I'm currently at an IT department that allows dual boot with Windows and Linux, but some run Linux while the vast majority use Windows. Here's several advantages that I've came up with since using Linux as a primary desktop. Same Exact operating system as Dev, QA, and Production Same Scripts (.sh) instead of maintaining (.bat and *.sh). Somewhat mitigated by using cygwin, but still a bit different. Team learns simple commands such as: cd, ls, cat, top Team learns Advanced commands like: pkill, pgrep, chmod, su, sudo, ssh, scp Full access to installs typically for Linux, such as RPM, DEB installs just like the target environments. The list could go on and on, but I want to get some feedback of anything that I may have missed, or even any disadvantages (of course there are some). To me it makes sense to migrate an entire team over to using Linux, and using Virtual Box, running Windows XP VM's to test functional items that 95% of most of the world uses. This is similar but a little different thread going on here as well. link text

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• Upload using python script takes very long on one laptop as compared to another

  - by Engr Am

  I have a python 2.7 code which uses STORBINARY function for uploading files to an ftp server and RETRBINARY for downloading from this server. However, the issue is the upload is taking a very long time on three laptops from different brands as compared to a Dell laptop. The strange part is when I manually upload any file, it takes the same time on all the systems. The manual upload rate and upload rate with the python script is the same on the Dell Laptop. However, on every other brand of laptop (I have tried with IBM, Toshiba, Fujitsu-Siemens) the python script has a very low upload rate than the manual attempt. Also, on all these other laptops, the upload rate using the python script is the same (1Mbit/s) while the manual upload rate is approx. 8 Mbit/s. I have tried to vary the filesize for the upload to no avail. TCP Optimizer improved the download rate on all the systems but had no effect on the upload rate. Download rate using this script on all the systems is fine and same as the manual download rate. I have checked the server and it has more than 90% free space. The network connection is the same for all the laptops, and I try uploading only with one laptop at a time. All the laptops have almost the same system configurations, same operating system and approximately the same free drive space. If anything the Dell laptop is a little less in terms of processing power and RAM than 2 of the others, but I suppose this has no effect as I have checked many times to see how much was the CPU usage and network usage during these uploads and downloads, and I am sure that no other virus or program has been eating up my bandwidth. Here is the code ('ftp' and 'file_path' are inputs to the function): path,filename=os.path.split(file_path) filesize=os.path.getsize(file_path) deffilesize=(filesize/1024)/1024 f = open(file_path, "rb") upstart = time.clock() print ftp.storbinary("STOR "+filename, f) upende = time.clock()-upstart outname="Upload " f.close() return upende, deffilesize, outname

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• WM_NOTIFY and superclass chaining issue in Win32

  - by DasMonkeyman

  For reference I'm using the window superclass method outlined in this article. The specific issue occurs if I want to handle WM_NOTIFY messages (i.e. for custom drawing) from the base control in the superclass I either need to reflect them back from the parent window or set my own window as the parent (passed inside CREATESTRUCT for WM_(NC)CREATE to the base class). This method works fine if I have a single superclass. If I superclass my superclass then I run into a problem. Now 3 WindowProcs are operating in the same HWND, and when I reflect WM_NOTIFY messages (or have them sent to myself from the parent trick above) they always go to the outermost (most derived) WindowProc. I have no way to tell if they're messages intended for the inner superclass (base messages are supposed to go to the first superclass) or messages intended for the outer superclass (messages from the inner superclass are intended for the outer superclass). These messages are indistinguishable because they all come from the same HWND with the same control ID. Is there any way to resolve this without creating a new window to encapsulate each level of inheritance? Sorry about the wall of text. It's a difficult concept to explain. Here's a diagram. single superclass: SuperA::WindowProc() - Base::WindowProc()---\ ^--------WM_NOTIFY(Base)--------/ superclass of a superclass: SuperB::WindowProc() - SuperA::WindowProc() - Base::WindowProc()---\ ^--------WM_NOTIFY(Base)--------+-----------------------/ ^--------WM_NOTIFY(A)-----------/ The WM_NOTIFY messages in the second case all come from the same HWND and control ID, so I cannot distinguish between the messages intended for SuperA (from Base) and messages intended for SuperB (from SuperA). Any ideas?

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• Attempting to Convert Byte[] into Image... but is there platform issues involved

  - by user305535

  Greetings, Current, I'm attempting to develop an application that takes a Byte Array that is streamed to us from a Linux C language program across a TCPClient (stream) and reassemble it back into an image/jpg. The "sending" application was developed by a off-site developer who claims that the image reassembles back into an image without any problems or errors in his test environment (all Linux)... However, we are not so fortunate. I (believe) we successfully get all of the data sent, storing it as a string (lets us append the stream until it is complete) and then we convert it back into a Byte[]. This appears to be working fine... But, when we take the byte[] we get from the streaming (and our string assembly) and try to convert it into an image using the System.Drawing.Image.FromStream() we get errors.... Anyone have any idea what we're doing wrong? Or, does anyone know if this is a cross-platform issue? We're developing our app for Windows XP and C# .net, but the off-site developer did his work in c and Linux... perhaps there's some difference as to how each Operating System Coverts Images into Byte Arrays? Anyway, here's the code for converting our received ByteArray (from the TCPClient Stream) into an image. This code works when we send an image from a test machine we built that RUNS on XP, but not from the Linux box... System.Text.ASCIIEncoding encoding = new System.Text.ASCIIEncoding(); byte[] imageBytes = encoding.GetBytes(data); MemoryStream ms = new MemoryStream(imageBytes, 0, imageBytes.Length); // Convert byte[] to Image ms.Write(imageBytes, 0, imageBytes.Length); System.Drawing.Image image = System.Drawing.Image.FromStream(ms, false); <-- DIES here, throws a {System.ArgumentException: Parameter is not valid.} error Any advice, suggestions, theories, or HELP would be GREATLY appreciated! Please let me know??? Best wishes all! Thanks in advance! Greg

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• Tablet interface for the physically disabled?

  - by Glenn

  My sister has Cerebral Palsy, which in her case means she has only gross motor control and her speech is slurred. Implications should be obvious: traditional computer/phone/tablet interfaces won't work for her and she can't speak clearly enough for speech recognition software to help her at all. She enjoys reading but has difficulty holding the book and/or turning a page. There are a few options for helping her use a computer, but nothing for tablets or eReaders. That's where you come in. I would like to make (or buy, if such a thing exists) a better interface to an Android tablet that would work for someone with little to no physical dexterity or speech ability. I'd also be interested in work on the Kindle or iPad, but I'm most familiar with Android so I'm starting there. I know Android has Bluetooth capability. Is it possible to interface a joystick to control the Android device? By "control", I mean the entire operating system - selecting an app, launching it, controlling the menus, etc. I want to give her control over the whole thing, not just a specific app. On a PC this can be accomplished by creating a generic USB HID interface and an arcade joystick to move the mouse over the screen and click on thigns. Is it possible to do something like that in Android? Any help you can offer would be greatly appreciated. Thanks!

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• php parsing speed optimization

  - by Arnaud

  I would like to add tooltip or generate link according to the element available in the database, for exemple if the html page printed is: to reboot your linux host in single-user mode you can ... I will use explode(" ", $row[page]) and the idea is now to lookup for every single word in the page to find out if they have a related referance in this exemple let's say i've got a table referance an one entry for reboot and one for linux reboot: restart a computeur linux: operating system now my output will look like (replaced < and by @) to @a href="ref/reboot"@reboot@/a@ your @a href="ref/linux"@linux@/a@ host in single-user mode you can ... Instead of have a static list generated when I saved the content, if I add more keyword in the future, then the text will become more interactive. My main concerne and question is how can I create a efficient enough process to do it ? Should I store all the db entry in an array and compare them ? Do an sql query for each word (seems to be crazy) Dump the table in a file and use a very long regex or a "grep -f pattern data" way of doing it? Or or or or I'm sure it must be a better way of doing it, just don't have a clue about it, or maybe this will be far too resource un-friendly and I should avoid doing such things. Cheers!

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• With a browser, how do I know which decimal separator does the client use?

  - by Quassnoi

  I'm developing a web application. I need to display some decimal data correctly so that it can be copied and pasted into a certain GUI application that is not under my control. The GUI application is locale sensitive and it accepts only the correct decimal separator which is set in the system. I can guess the decimal separator from Accept-Language and the guess will be correct in 95% cases, but sometimes it fails. Is there any way to do it on server side (preferably, so that I can collect statistics), or on client side? Update: The whole point of the task is doing it automatically. In fact, this webapp is a kind of online interface to a legacy GUI which helps to fill the forms correctly. The kind of users that use it mostly have no idea on what a decimal separator is. The Accept-Language solution is implemented and works, but I'd like to improve it. Update2: I need to retrive a very specific setting: decimal separator set in Control Panel / Regional and Language Options / Regional Options / Customize. I deal with four kinds of operating systems: Russian Windows with a comma as a DS (80%). English Windows with a period as a DS (15%). Russian Windows with a period as a DS to make poorly written English applications work (4%). English Windows with a comma as a DS to make poorly written Russian applications work (1%). All 100% of clients are in Russia and the legacy application deals with Russian goverment-issued forms, so asking for a country will yield 100% of Russian Federation, and GeoIP will yield 80% of Russian Federation and 20% of other, incorrect answers.

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• Optimal Eclipse CDT (C++) experience in March of 2010

  - by ahoffer

  I am a student who will be using C++ next quarter. I really enjoyed using the Galileo release of Eclipse with Java and I would like to continue using Eclipse for for C++ development. I am now experimenting with C++ development on Eclipse. I am running Eclipse 3.5 SR2 with CDT 6.02. My operating system is Windows 7 and I have installed MinGW-5.1.6. Version 6.3 of GDB is installed. I have it compiling and stepping through code. However, I have the suspicion that I'm just crawling along and have yet to "shift the car out of first gear". I've spent about a week poking around on the Web to learn what constitutes and "optimal" C++ Eclipse experience. In particular, I'm interested in round-tripping with UML and unit testing. My exploration of the Web became an archeological dig. I turned up how-to articles from 2003, alternative MinGW distros, references to plugins, dead-links, more references to plugins, passionate discussions on gdb bugs, and more references to plugins. I no longer have any idea what might constitute an optimal C++ Eclipse environment. Would members of the community like to weigh-in on what they consider to be the current optimal experience for C++ development using Eclipse?

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• Should a Trim method generally in the Data Access Layer or with in the Domain Layer?

  - by jpierson

  I'm dealing with a database that contains data with inconsistencies such as white leading and trailing white space. In general I see a lot of developers practice defensive coding by trimming almost all strings that come from the database that may have been entered by a user at some point. In my oppinoin it is better to do such formating before data is persisted so that it is done only once and then the data can be in a consistent and reliable state. Unfortunatley this is not the case however which leads me to the next best solution, using a Trim method. If I trim all data as part of my data access layer then I don't have to concern myself with defensive trimming within the business objects of my domain layer. If I instead put the trimming responsibility in my business objects, such as with set accessors of my C# properties, I should get the same net results however the trim will be operating on all values assigned to my business objects properties not just the ones that come from the inconsistent database. I guess as a somewhat philisophical question that may determine the answer I could ask "Should the domain later be responsible for defensive/coercive formatting of data?" Would it make sense to have a set accessor for a PhoneNumber property on a business object accept a unformatted or formatted string and then attempt to format it as required or should this responsibility be pushed to the presentation and data access layers leaving the domain layer more strict in the type of data that it will accept? I think this may be the more fundamental question. Update: Below are a few links that I thought I should share about the topic of data cleansing. Information service patterns, Part 3: Data cleansing pattern LINQ to SQL - Format a string before saving? How to trim values using Linq to Sql?

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• How do I create an "iframe popup" when I hover over an <a> tag?

  - by Angela

  Here is the scenario: a User will see a list of company names, each wrapped in an tag. He is able to see dynamic information and as he hover over each name and then make a request. So Given a list of companies, each wrapped in an tag. When the cursor hovers over an tag Then a "pop-up" appears that contains an -based, dynamic content. Given the pop-up When the User clicks on the "submit" button in the pop-up Then the form (based on the framework" is submitted and ajax displays "request succesful" So, because I am using a php-framework, I'd like to use iframe to contain the form. Some challenges: When the cursor is no longer hovering over the tag, the hover disappears. How do I keep it operating? How do I make it appear in an so I can have full form-submission and POST-ing dynamic values through the URL? How do the "popup" disappear when the cursor is no longer on either the -tag or the pop-up itself? Can I do it without loading a bunch of 's onto the page, because the list of companies could be long.

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• How to create platform independent 3D video on 3D TV via HDMI 1.4?

  - by artif

  I am writing a real-time, interactive 3D visualization program and at each point in the program, I can compute 2 images (bitmaps) that are meant to look 3D together by means of stereoscopy. How do I get my program to display the image pairs such that they look 3D on a 3D TV? Is there a platform independent way of accomplishing it? (By platform I mean independent of GPU brand, operating system, 3D TV vendor, etc.) If not, which is preferable-- to lock in by GPU, OS, or 3D TV? I suppose I need to be using an HDMI 1.4 cable with the 3D TV? HDMI 1.4 can encode stereoscopy via side-by-side method. But how do I send such an encoded signal to the monitor? What kind of libraries do I use for this sort of thing? Windows DirectShow? If DirectShow is correct, is there a cross platform equivalent available? If anyone asks, yes I have seen this question: http://stackoverflow.com/questions/2811350/generating-3d-tv-stereoscopic-output-programmatically. However, correct me if I am wrong, it does not appear to be what I'm looking for. I do not have an OpenGL or Direct3D program that generates polygons, for which a Nvidia card can do ad-hoc impromptu stereoscopy simply by rendering the scene from 2 slightly offset points of view and then displaying those 2 images on the monitor-- my program already has those image pairs and needs to display them (and they are not the result of rendering polygons). Btw, I have never done any major multimedia programming before and know very little about HDMI, Direct Show, 3D TVs, etc so pardon me if any parts of this question did not make any sense at all.

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• Agile language for 2d game prototypes?

  - by instanceofTom

  Occasionally ( read: when my fiancé allows ) I like to prototype different game or game-like ideas I have. Usually I use Java or C# (not xna yet) because they are the languages I have the most practice with. However I would like to learn something more suited to agile development; a language in which it would be easier to knock out quick prototypes. At my job I have recently been working with looser (weak/dynamically typed) languages, specifically python and groovy, and I think something similar would fit what I am looking for. So, my question is: What languages (and framework/engine) would be good for rapidly developing prototypes of 2d game concepts? A few notes: I don't need blazing fast bitcrunching performance. In this case I would strongly prefer ease of development over performance. I'd like to use a language with a healthy community, which to me means a fair amount of maintained 3rd party, libraries. I'd like the language to be cross-platform friendly, I work on a variety of different operating systems and would like something that is portable with minimum effort. I can't imagine myself using a language with out decent options for debugging and editor syntax highlighting support. Note: If you are aware of a Java or C# library/framework that you think streamlines producing game prototypes I open to learning something new for those languages too

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• Shared Memory and Process Sempahores (IPC)

  - by fsdfa

  This is an extract from Advanced Liniux Programming: Semaphores continue to exist even after all processes using them have terminated. The last process to use a semaphore set must explicitly remove it to ensure that the operating system does not run out of semaphores.To do so, invoke semctl with the semaphore identifier, the number of semaphores in the set, IPC_RMID as the third argument, and any union semun value as the fourth argument (which is ignored).The effective user ID of the calling process must match that of the semaphore’s allocator (or the caller must be root). Unlike shared memory segments, removing a semaphore set causes Linux to deallocate immediately. If a process allocate a shared memory, and many process use it and never set to delete it (with shmctl), if all them terminate, then the shared page continues being available. (We can see this with ipcs). If some process did the shmctl, then when the last process deattached, then the system will deallocate the shared memory. So far so good (I guess, if not, correct me). What I dont understand from that quote I did, is that first it say: "Semaphores continue to exist even after all processes using them have terminated." and then: "Unlike shared memory segments, removing a semaphore set causes Linux to deallocate immediately."

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• How is a referencing environment generally implemented for closures?

  - by Alexandr Kurilin

  Let's say I have a statically/lexically scoped language with deep binding and I create a closure. The closure will consist of the statements I want executed plus the so called referencing environment, or, to quote this post, the collection of variables which can be used. What does this referencing environment actually look like implementation-wise? I was recently reading about ObjectiveC's implementation of blocks, and the author suggests that behind the scenes you get a copy of all of the variables on the stack and also of all the references to heap objects. The explanation claims that you get a "snapshot" of the referencing environment at the point in time of the closure's creation. Is that more or less what happens, or did I misread that? Is anything done to "freeze" a separate copy of the heap objects, or is it safe to assume that if they get modified between closure creation and the closure executing, the closure will no longer be operating on the original version of the object? If indeed there's copying being made, are there memory usage considerations in situations where one might want to create plenty of closures and store them somewhere? I think that misunderstanding of some of these concepts might lead to tricky issues like the ones Eric Lippert mentions in this blog post. It's interesting because you'd think that it wouldn't make sense to keep a reference to a value type that might be gone by the time the closure is called, but I'm guessing that in C# the compiler will figure out that the variable is needed later and put it into the heap instead. It seems that in most memory-managed languages everything is a reference and thus ObjectiveC is a somewhat unique situation with having to deal with copying what's on the stack.

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• How to benchmark on multi-core processors

  - by Pascal Cuoq

  I am looking for ways to perform micro-benchmarks on multi-core processors. Context: At about the same time desktop processors introduced out-of-order execution that made performance hard to predict, they, perhaps not coincidentally, also introduced special instructions to get very precise timings. Example of these instructions are rdtsc on x86 and rftb on PowerPC. These instructions gave timings that were more precise than could ever be allowed by a system call, allowed programmers to micro-benchmark their hearts out, for better or for worse. On a yet more modern processor with several cores, some of which sleep some of the time, the counters are not synchronized between cores. We are told that rdtsc is no longer safe to use for benchmarking, but I must have been dozing off when we were explained the alternative solutions. Question: Some systems may save and restore the performance counter and provide an API call to read the proper sum. If you know what this call is for any operating system, please let us know in an answer. Some systems may allow to turn off cores, leaving only one running. I know Mac OS X Leopard does when the right Preference Pane is installed from the Developers Tools. Do you think that this make rdtsc safe to use again? More context: Please assume I know what I am doing when trying to do a micro-benchmark. If you are of the opinion that if an optimization's gains cannot be measured by timing the whole application, it's not worth optimizing, I agree with you, but I cannot time the whole application until the alternative data structure is finished, which will take a long time. In fact, if the micro-benchmark were not promising, I could decide to give up on the implementation now; I need figures to provide in a publication whose deadline I have no control over.

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• Read a specific range of lines from a file using c

  - by James Joy

  I have the following content in a file: hhasfghgsafjgfhgfhjf gashghfdgdfhgfhjasgfgfhsgfjdg jfshafghgfgfhfsghfgffsjgfj . . . . . startread hajshjsfhajfhjkashfjf hasjgfhgHGASFHGSHF hsafghfsaghgf . . . . . stopread . . . . . . jsfjhfhjgfsjhfgjhsajhdsa jhasjhsdabjhsagshaasgjasdhjk jkdsdsahghjdashjsfahjfsd I need to read the lines from the next line of startread till the previous line of stopread using a c code and store it to a string variable(of course with a \n for every line breaks). How can i achieve this? I have used fgets(line,sizeof(line),file); but it starts reading from the beginning. I don't have the exact line number to start and stop reading since the file is written by another C code. But there are these identifiers startread and stopread to identify whereto start reading. Operating platform is linux. Thanks in advance.

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• Is there a way to increase the efficiency of shared_ptr by storing the reference count inside the co

  - by BillyONeal

  Hello everyone :) This is becoming a common pattern in my code, for when I need to manage an object that needs to be noncopyable because either A. it is "heavy" or B. it is an operating system resource, such as a critical section: class Resource; class Implementation : public boost::noncopyable { friend class Resource; HANDLE someData; Implementation(HANDLE input) : someData(input) {}; void SomeMethodThatActsOnHandle() { //Do stuff }; public: ~Implementation() { FreeHandle(someData) }; }; class Resource { boost::shared_ptr<Implementation> impl; public: Resource(int argA) explicit { HANDLE handle = SomeLegacyCApiThatMakesSomething(argA); if (handle == INVALID_HANDLE_VALUE) throw SomeTypeOfException(); impl.reset(new Implementation(handle)); }; void SomeMethodThatActsOnTheResource() { impl->SomeMethodThatActsOnTheHandle(); }; }; This way, shared_ptr takes care of the reference counting headaches, allowing Resource to be copyable, even though the underlying handle should only be closed once all references to it are destroyed. However, it seems like we could save the overhead of allocating shared_ptr's reference counts and such separately if we could move that data inside Implementation somehow, like boost's intrusive containers do. If this is making the premature optimization hackles nag some people, I actually agree that I don't need this for my current project. But I'm curious if it is possible.

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• PHP - upload.class image and $_FILES

  - by Ockonal

  Hello, I'm using class.upload.php to upload pictures onto the server. Here is my form: <form action="<?="http://".$_SERVER['SERVER_NAME'].$_SERVER['REQUEST_URI'];?>" method="post" enctype="multipart/form-data"> <table style="width: 100%; padding-top: 20px;"> <tr> <td>Image file:</td> <td><input type="file" name="image_file" /></td> </tr> <tr> <td>&nbsp;</td> <td align="right"><input type="submit" name="add_new" value="Add image" /><td></td> </tr> </table> </form> In php code I do: if( array_key_exists('add_new', $_POST) ) { echo 'add new is in array'; echo '<pre>'; print_r($_POST); print_r($_FILES); echo '</pre>'; $handle = new Upload($_FILES['image_file']); ... } Here is an output of print_r: Array ( [image_file] => somefile.png [add_new] => Add image ) Array ( ) As you can see second array is empty ($_FILES), so image doesn't upload. Why? operating system : Linux PHP version : 5.2.12 GD version : 2.0.34 supported image types : png jpg gif bmp open_basedir : /home/httpd/vhosts/kz-gbi.ru/httpdocs:/tmp

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• Python modules not updating after restarting the main module.

  - by Ian

  I've recently come back to a project having had to stop for about 6 months, and after reinstalling my operating system and coming back to it I'm having all kinds of crazy things happen. I made sure to install the same version(2.6) of python that I was using before. It started by giving me strange tkinter error that I hadn't had trouble with before, the program is relatively simple and the 2 or 3 bugs that were left when i quit, I had documented and weren't related to the interface. Things got even weirder when the same error would pop up even after I had removed the offending section of code. In fact, the traceback pointed to a line that didn't even exist in the module it was referencing, eg: line 262 when the module was only 200 lines long. After just starting a completely new file for the main module and copy/pasting it finally recognized that the offending code was gone and I stopped getting the error only to find that any updates to the code I made in another module didn't show up when I restarted the program through the shell. (I didn't forget to save.) After fiddling with this, of course, the old interface error came back, only in a different section of code that had been working previously. In fact, if I revert back to the files I had six months ago, the program works fine. As soon as I change anything in the main module, however, the interface bug comes back. Here's the original error: Exception in Tkinter callback Traceback (most recent call last): File "C:\Python26\lib\lib-tk\Tkinter.py", line 1410, in __call__ return self.func(*args) File "C:\PyStuff\interface.py", line 202, in dispOne __main__.top.destroy() File "C:\Python26\lib\lib-tk\Tkinter.py", line 1938, in destroy self.tk.call('destroy', self._w) TclError: can't invoke "destroy" command: application has been destroyed I'm guessing something else is going on here other than my own poor programming. Anyone have any ideas?

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• How to create nested ViewComponents in Monorail and NVelocity?

  - by rob_g

  I have been asked to update the menu on a website we maintain. The website uses Castle Windors Monorail and NVelocity as the template. The menu is currently rendered using custom made subclasses of ViewComponent, which render li elements. At the moment there is only one (horizontal) level, so the current mechanism is fine. I have been asked to add drop down menus to some of the existing menus. As this is the first time I have seen Monorail and NVelocity, I'm a little lost. What currently exists: <ul> #component(MenuComponent with "title=Home" "hover=autoselect" "link=/") #component(MenuComponent with "title=Videos" "hover=autoselect") #component(MenuComponent with "title=VPS" "hover=autoselect" "link=/vps") #component(MenuComponent with "title=Add-Ons" "hover=autoselect" "link=/addons") #component(MenuComponent with "title=Hosting" "hover=autoselect" "link=/hosting") #component(MenuComponent with "title=Support" "hover=autoselect" "link=/support") #component(MenuComponent with "title=News" "hover=autoselect" "link=/news") #component(MenuComponent with "title=Contact Us" "hover=autoselect" "link=/contact-us") </ul> Is it possible to have nested MenuComponents (or a new SubMenuComponent) something like: <ul> #component(MenuComponent with "title=Home" "hover=autoselect" "link=/") #component(MenuComponent with "title=Videos" "hover=autoselect") #blockcomponent(MenuComponent with "title=VPS" "hover=autoselect" "link=/vps") #component(SubMenuComponent with "title="Plans" "hover=autoselect" "link=/vps/plans") #component(SubMenuComponent with "title="Operating Systems" "hover=autoselect" "link=/vps/os") #component(SubMenuComponent with "title="Supported Applications" "hover=autoselect" "link=/vps/apps") #end #component(MenuComponent with "title=Add-Ons" "hover=autoselect" "link=/addons") #component(MenuComponent with "title=Hosting" "hover=autoselect" "link=/hosting") #component(MenuComponent with "title=Support" "hover=autoselect" "link=/support") #component(MenuComponent with "title=News" "hover=autoselect" "link=/news") #component(MenuComponent with "title=Contact Us" "hover=autoselect" "link=/contact-us") </ul> I need to draw the sub menu (ul and li elements) inside the overridden Render method on MenuComponent, so using nested ViewComponent derivatives may not work. I would like a method keep the basically declarative method for creating menus, if at all possible.

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