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  • Fault exception trashes a register causing a crash in [NSInvocation invoke]

    - by Mike Weller
    I have an NSOperation which fetches some objects from a core data persistent store and sums up a few totals. Sometimes an object is deleted while the operation in in progress, so a core data fault exception occurs. I try/catch the exception while summing to ignore it because I just want to skip objects that cannot be faulted in. However, when one of these fault exceptions occurs (and I swallow it) there is a crash after the invocation returns in [NSInvocation invoke]. It's a bad memory access when dereferencing the value in r10 which according to GDB on a successful run points to one of these: (gdb) x 0x38388348 0x38388348 <OBJC_IVAR_$_NSInvocation._retdata>: 0x00000008 If a fault exception occured a value of 0x02 is in the register which causes the crash. A quick google search tells me that r10 should be saved by the callee, meaning it is not being restored by whatever code is changing it when this exception occurs. Can anybody explain this? I'm not an expert when it comes to these kinds of low-level details

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  • Will Emacs --batch run in cron will hang when require user input?

    - by J Spen
    I have a job in crontab that requires emacs --batch but if the file is currently open it requests (s, p, q) to (steal, quit, etc...) which is fine if this file is being edited to not run the script but I want to make sure it kills the cron running script so it's not sitting in the background taking up memory. I have the output set to go to a log file so I can see this happening but no way to tell whether the script was terminated even though asked for user input. Does cron terminate these scripts and how to check the PID to make sure?

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  • How do you mentally handle going from writing managed to non-managed code?

    - by Glenn Sandoval
    ~80% of the code I write is in C#. The other ~20% is in C++. Whenever I have to switch from C# to C++, it takes me quite a while to mentally "shift gears" to thinking in C++. I make simple mistakes using pointers and memory allocation that I would not have made when I was in university. Is this normal? Does anyone else experience something similar and if so, what do you do to cut down on the time this wastes?

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  • Is there a way to read 10000 lines from a file in python?

    - by windsound
    I am relatively new in python, was working on C a lot. Since I was seeing so many new functions in python that I do not know, I was wondering if there is a function that can request 10000 lines from a file in python. Something like this is what I expect if that kind of function exist: lines = get_10000_lines(file_pointer) Did python have a build-in function or is there any module that I can download for this? If not, how do I do this to be easiest way. I need to analyze a huge file so I want to read 10000 lines and analyze per time to save memory. Thanks for helping!

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  • Are @property's necessary for Interface Builder?

    - by Rits
    In my UIViewController subclass, I have 3 UIView's with each a @property as an IBOutlet. I do not use these properties at all in my code. The views get instantiated as soon as the view controller is created and they are deallocated when the view controller is deallocated. I was thinking; can't I just remove the @property's? I did, and I could still connect my instance variables (with IBOutlet) in Interface Builder. So my question now is; is there any use for properties in combination with Interface Builder, or is it OK to leave them out? Is it required for some memory management or something? Or are they really just for use in your own code? And if I do leave them out, do I still need to release them in dealloc?

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  • Free object/widget in GTK?

    - by wag2639
    I've got a pack box in my GTK application and I'm replacing it every once in a while with a completely new entry (at least for now cause I'm in a hurry). Since I'm replacing it with a new instance, do I need to explicitly free from memory the old pack box contents or is there some garbage collection in GTK? If I do need to explicitly need to free the object, is there a command that will recursively go to all objects in that tree (like will it clear my button in a box container inside my main pack box)? I'm using C/GTK-2.0 (gcc v4.4.3 and GTK 2.20.0).

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  • Primary language - QtC++, C#, Java?

    - by Airjoe
    I'm looking for some input, but let me start with a bit of background (for tl;dr skip to end). I'm an IT major with a concentration in networking. While I'm not a CS major nor do I want to program as a vocation, I do consider myself a programmer and do pretty well with the concepts involved. I've been programming since about 6th grade, started out with a proprietary game creation language that made my transition into C++ at college pretty easy. I like to make programs for myself and friends, and have been paid to program for local businesses. A bit about that- I wrote some programs for a couple local businesses in my senior year in high school. I wrote management systems for local shops (inventory, phone/pos orders, timeclock, customer info, and more stuff I can't remember). It definitely turned out to be over my head, as I had never had any formal programming education. It was a great learning experience, but damn was it crappy code. Oh yeah, by the way, it was all vb6. So, I've used vb6 pretty extensively, I've used c++ in my classes (intro to programming up to algorithms), used Java a little bit in another class (had to write a ping client program, pretty easy) and used Java for some simple Project Euler problems to help learn syntax and such when writing the program for the class. I've also used C# a bit for my own simple personal projects (simple programs, one which would just generate an HTTP request on a list of websites and notify if one responded unexpectedly or not at all, and another which just held a list of things to do and periodically reminded me to do them), things I would've written in vb6 a year or two ago. I've just started using Qt C++ for some undergrad research I'm working on. Now I've had some formal education, I [think I] understand organization in programming a lot better (I didn't even use classes in my vb6 programs where I really should have), how it's important to structure code, split into functions where appropriate, document properly, efficiency both in memory and speed, dynamic and modular programming etc. I was looking for some input on which language to pick up as my "primary". As I'm not a "real programmer", it will be mostly hobby projects, but will include some 'real' projects I'm sure. From my perspective: QtC++ and Java are cross platform, which is cool. Java and C# run in a virtual machine, but I'm not sure if that's a big deal (something extra to distribute, possibly a bit slower? I think Qt would require additional distributables too, right?). I don't really know too much more than this, so I appreciate any help, thanks! TL;DR Am an avocational programmer looking for a language, want quick and straight forward development, liked vb6, will be working with database driven GUI apps- should I go with QtC++, Java, C#, or perhaps something else?

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  • How can I determine whether xml serializer can serialize a file

    - by ldsenow
    Hi, How can I determine whether xml serializer can serialize a file which is in a shared location and monitored by a file monitor. The file monitor has a list of parsers which are used to parse files in the shared folder. Once a file gets dropped into the folder, the file monitor will ask the registered parsers whether any of them can handle this file, if yes, the monitor will move the file out from the shared folder and assigns the task to the parser. Since some of the files are quite big, so I need to have a quick check on each parsers. How can I determine my xml parser can serialize the file without loading the full file into the memory?

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  • Shortest command to calculate the sum of a column of output on Unix?

    - by Andrew
    I'm sure there is a quick and easy way to calculate the sum of a column of values on Unix systems (using something like awk or xargs perhaps), but writing a shell script to parse the rows line by line is the only thing that comes to mind at the moment. For example, what's the simplest way to modify the command below to compute and display the total for the SEGSZ column (70300)? ipcs -mb | head -6 IPC status from /dev/kmem as of Mon Nov 17 08:58:17 2008 T ID KEY MODE OWNER GROUP SEGSZ Shared Memory: m 0 0x411c322e --rw-rw-rw- root root 348 m 1 0x4e0c0002 --rw-rw-rw- root root 61760 m 2 0x412013f5 --rw-rw-rw- root root 8192

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  • Insert problem using ADO with classic ASP

    - by Kemal Akcali
    ' Setting variables Dim con, sql_insert, data_source data_source = "project_db" sql_insert = "insert into cart ( UserID,Count,ProductName,ProductDescription,ProductPrice) values ('"&user_id&"','"&count&"','"&product_name&"','"&product_description&"','"&product_price&"')" ' Creating the Connection Object and opening the database Set con = Server.CreateObject("ADODB.Connection") con.Open data_source ' Executing the sql insertion code con.Execute sql_insert ' Done. Now Close the connection con.Close Set con = Nothing AS you can see , it is a simple code . and it worked in my local host for 5 or 6 times. but now it didn't work. What's the problem ? I think , it's about my database or memory. i setup 2 different iis in 2 different computer and they behave same... please help.. Thanks

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  • Is it a good idea to define a variable in a local block for a case of a switch statement?

    - by Paperflyer
    I have a rather long switch-case statement. Some of the cases are really short and trivial. A few are longer and need some variables that are never used anywhere else, like this: switch (action) { case kSimpleAction: // Do something simple break; case kComplexAction: { int specialVariable = 5; // Do something complex with specialVariable } break; } The alternative would be to declare that variable before going into the switch like this: int specialVariable = 5; switch (action) { case kSimpleAction: // Do something simple break; case kComplexAction: // Do something complex with specialVariable break; } This can get rather confusing since it is not clear to which case the variable belongs and it uses some unnecessary memory. However, I have never seen this usage anywhere else. Do you think it is a good idea to declare variables locally in a block for a single case?

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  • How to download files directly to disk on the iPhone os?

    - by favo
    Hi, I would like to download files directly from an URL to the disk using objective-c on the iPhone os. Currently I am using NSURLConnection to send a synchronousRequest, writing the returned NSData into a file. How can I change the download handling (still having the request beeing synchronous, it is already in a background thread) to write the data directly to disk, not using memory variables to store the complete content (only small parts)? A sample code would be appreciated. Thank you all in advance for your responses!

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  • iphone - how to properly handle exceptional situations (signals ?)

    - by pmilosev
    Hi In my iphone app, I want to provide some sort of app termination handler that will do some final work (delete some sensitive data) before the application terminates. I want to handle as much of the termination situations as possible: 1) User terminates the app 2) The device runs out of battery 3) The system terminates the app due to some reason (e.g. out of memory or app freeze) 4) Application crashes (EXC_BAD_ACCESS or SIGSEGV) Any other exceptional situation ? What is the best way to achieve this (e.g. is applicationWillTerminate method called in situation 2) ? Is it possible to do the cleanup in a signal handler (includes iPhone Security framework calls) ? regards

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  • Import small number of records from a very large CSV file in Biztalk 2006

    - by rwmnau
    I have a Biztalk project that imports an incoming CSV file and dumps it to a database table. The import works fine, but I only need to keep about 200-300 records from a file with upwards of a million rows. My orchestration discards these rows, but the problem is that the flat file I'm importing is still 250MB, and when converted to XML using a regular flat file pipeline, it takes hours to process and sometimes causes the server to run out memory. Is there something I can do to have the Custom Pipeline itself discard rows I don't care about? The very first item in each CSV row is one of a few strings, and I only want to keep rows that start with a certain string. Thanks for any help you're able to provide.

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  • HTTP Download very Big File

    - by Luca
    I'm working at a web application in Python/Twisted. I want the user to be able to download a very big file ( 100 Mb). I don't want to load all the file in memory (of the server), of course. server side I have this idea: ... request.setHeader('Content-Type', 'text/plain') fp = open(fileName, 'rb') try: r = None while r != '': r = fp.read(1024) request.write(r) finally: fp.close() request.finish() I expected this to work, but I have problems: I'm testing with FF... It seems the browser make me wait until the file is completed downloaded, and then I have the open/save dialog box. I expected the dialog box immediately, and then the progress bar in action... Maybe I have to add something in the Http header... Something like the size of the file?

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  • How to create an iPad directory view like animation?

    - by mahes25
    In the recent iOS 4.2 update, Apple introduced a nice animation for creating one level directories. I am trying to figure out how to implement a similar animation in my project. I would deeply appreciate it if anyone could give me any pointers to do this efficiently. From my investigation, I believe this animation or effect could be done very efficiently using Core Image which would allow me to write a custom filter. Unfortunately, Core Image is not available in iPhone. So how can do it? I read a blog post that explained a core animation scheme to create an iPad flip clock. The problem I have is similar but has important differences. Besides, I not excited about saving the subimage combinations, which I believe can cause a memory issue. Please enlighten me on the possible ways of doing this animation. I am relatively new to iOS programming, so I might have missed obvious ways of doing this animation or effect.

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  • Does anyone else think instance variables are problematic in database-backed applications?

    - by Ben Aston
    It occurs to me that state control in languages like C# is not well supported. By this, I mean, it is left upto the programmer to manage the state of in-memory objects. A common use-case is that instance variables in the domain-model are copies of information residing in persistent storage (i.e. the database). Clearly this violates the single point of authority principle, and "synchronisation" has to be managed by the developer. I envisage a system where instead of instance variables, we have simple public access/mutator methods marked with attributes that link them to the database, and where reads and writes are mediated by a framework that decides whether to hit the database. Does such a system exist? Am I completely missing the point, or is there some truth to this idea?

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  • PHP reporting error. DB verify how to?

    - by iamfab
    Error reporting Notice: Undefined variable: random_chars in wamp\www\php_sandbox\idgen.php on line 21 Call Stack: # Time Memory Function Location 1 0.0045 678928 {main}( ) ..\idgen.php:0 GPB7446 How do I fix this error? Using this code like an automatic unique id generator. How do I connect to DB to verify code is truly unique before allowing it to be assigned to a user creating a new account? Thanks <?php $characters = array( "A","B","E","F","G","H","J","K","M","N","P","R","S","T","W","X","Y","Z"); $keys = array(); while(count($keys) < 3) { $x = mt_rand(0, count($characters)-1); if(!in_array($x, $keys)) { $keys[] = $x; } } foreach($keys as $key){ $random_chars .= $characters[$key];} $randNum = rand(2327,9987); $randLet = rand(2327,9987); echo $random_chars . $randNum; ?>

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  • From xcode not able to execute DISTINCT keyword for sqlite

    - by mac
    -(void) readProductsFromDatabase { // Setup the database object sqlite3 *database; // Init the animals Array products = [[NSMutableArray alloc] init]; // Open the database from the users filessytem if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) { NSLog(@"db opened"); // Setup the SQL Statement and compile it for faster access const char *sqlStatement = "SELECT DISTINCT productname FROM iphone "; sqlite3_stmt *compiledStatement; if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) { // Loop through the results and add them to the feeds array while(sqlite3_step(compiledStatement) == SQLITE_ROW) { NSLog(@"inside sqlite3 prepare"); // Read the data from the result row NSString *aName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 2)]; } } // Release the compiled statement from memory sqlite3_finalize(compiledStatement); } sqlite3_close(database); } My problem is const char *sqlStatement = "SELECT DISTINCT productname FROM iphone "; This line not executing ,i am using sqlite3, thanks in advance,

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  • Strange errors in Visual C++ :: 'malloc' : function does not take 1 arguments

    - by pecker
    Error 38 error C2660: 'malloc' : function does not take 1 arguments C:\VolumeRenderer\render.cpp 296 1 VolumeRenderer Error 39 error C2660: 'malloc' : function does not take 1 arguments C:\VolumeRenderer\render.cpp 412 1 VolumeRenderer Error 40 error C2660: 'malloc' : function does not take 1 arguments C:\VolumeRenderer\render.cpp 414 1 VolumeRenderer Error 41 error C2660: 'read_den' : function does not take 4 arguments C:\VolumeRenderer\render.cpp 506 1 VolumeRenderer My all malloc sections are like this: /* allocate space for the raw data */ density_size = BRAIN_XLEN * BRAIN_YLEN * BRAIN_ZLEN; density = (unsigned char*)malloc(density_size); if (density == NULL) { fprintf(stderr, "out of memory\n"); exit(1); } regarding read_den (last error) unsigned char *read_den(char *filename,int *xptr,int *yptr,int *zptr)// function prototype src_volume = read_den(src_file, &src_xlen, &src_ylen, &src_zlen);// fucntion call Is it my code or the errors that are absurd. How to rectify them?

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  • Removing items from lists and all references to them.

    - by LiamV
    I'm facing a situation where I have dependent objects and I would like to be able to remove an object and all references to it. Say I have an object structure like the code below, with a Branch type which references two Nodes. public class Node { // Has Some Data! } public class Branch { // Contains references to Nodes public Node NodeA public Node NodeB } public class Graph { public List<Node> Nodes; public List<Branch> Branches; } If I remove a Node from the Nodes list in the Graph class, it is still possible that one or more Branch objects still contains a reference to the removed Node, thus retaining it in memory, whereas really what I would quite like would be to set any references to the removed Node to null and let the garbage collection kick in. Other than enumerating through each Branch and checking each Node reference sequentially, are there any smart ideas on how I remove references to the Node in each Branch instance AND indeed any other class which reference the removed Node?

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  • How do I bind a key to "the function represented by the following key sequence"?

    - by katrielalex
    I'm just starting to learn emacs (woohoo!) and I've been mucking around in my .emacs quite happily. Unfortunately, I don't know Lisp yet, so I'm having issues with the basics. I've already remapped a few keys until I fix my muscle memory: (global-set-key (kbd "<f9>") 'recompile) That's fine. But how can I tell a key to 'simulate pressing several keys'? For instance, I don't know, make <f1> do the same as C-u 2 C-x } (widen buffer by two chars). One way is to look up that C-x } calls shrink-window-horizontally, and do some sort of lambda thing. This is of course the neat and elegant way (how do you do this?). But surely there's a way to define <f1> to send the keystrokes C-u 2 C-x }?

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  • what mysql table structure is better

    - by Sergey
    I have very complicated search algorithm on my site, so i decided to make a table with cache or maybe all possible results. I wanna ask what structure would be better, or maybe not the one of them? (mySQL) 1) word VARCHAR, results TEXT or BLOB where i'll store ids of found objects (for example 6 chars for each id) 2) word VARCHAR, result INT, but words are not unique now i think i'll have about 200 000 rows in 1) with 1000-10000 ids each row or 200 000 000+ rows in 2) First way takes more storage memory but i think it would be much faster to find 1 unique row among 200 000, than 1000 rows among 200 mln non unique rows i think about index on word column and no sphinx. So that do YOU think? p.s. as always, sorry for my english if it's not very good.

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  • SQL Server 2008 vs 2005 udf xml perfomance problem.

    - by user344495
    Ok we have a simple udf that takes a XML integer list and returns a table: CREATE FUNCTION [dbo].[udfParseXmlListOfInt] ( @ItemListXml XML (dbo.xsdListOfInteger) ) RETURNS TABLE AS RETURN ( --- parses the XML and returns it as an int table --- SELECT ListItems.ID.value('.','INT') AS KeyValue FROM @ItemListXml.nodes('//list/item') AS ListItems(ID) ) In a stored procedure we create a temp table using this UDF INSERT INTO @JobTable (JobNumber, JobSchedID, JobBatID, StoreID, CustID, CustDivID, BatchStartDate, BatchEndDate, UnavailableFrom) SELECT JOB.JobNumber, JOB.JobSchedID, ISNULL(JOB.JobBatID,0), STO.StoreID, STO.CustID, ISNULL(STO.CustDivID,0), AVL.StartDate, AVL.EndDate, ISNULL(AVL.StartDate, DATEADD(day, -8, GETDATE())) FROM dbo.udfParseXmlListOfInt(@JobNumberList) TMP INNER JOIN dbo.JobSchedule JOB ON (JOB.JobNumber = TMP.KeyValue) INNER JOIN dbo.Store STO ON (STO.StoreID = JOB.StoreID) INNER JOIN dbo.JobSchedEvent EVT ON (EVT.JobSchedID = JOB.JobSchedID AND EVT.IsPrimary = 1) LEFT OUTER JOIN dbo.Availability AVL ON (AVL.AvailTypID = 5 AND AVL.RowID = JOB.JobBatID) ORDER BY JOB.JobSchedID; For a simple list of 10 JobNumbers in SQL2005 this returns in less than 1 second, in 2008 this run against the exact same data returns in 7 min. This is on a much faster machine with more memory. Any ideas?

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  • Does iOS 4 Have "Real" Multitasking?

    - by pkulak
    Ever since the first beta came out I've been trying to find out if "real" multitasking is possible. I.E., can you put a program in the background and have it hang on to a network connection indefinitely? I'm thinking about IM or IRC apps, for example. I've compiled an app myself on OS 4, and without changing a thing it appeared to stay running in the background, but for all I know it was just suspended to memory. The docs say the best you can do is request up to 10 minutes, but in the developer presentation they showed off Skype sitting in the background and then notifying the user that a call was coming in. Does anyone know for sure how this is all going to work?

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