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  • Is there a leak in this copy code?

    - by Don Wilson
    Is there a leak in this code? // Move the group Group *movedGroup = [[Group alloc] init]; movedGroup = [[[[GroupList sharedGroupList] groups] objectAtIndex:fromIndex] copy]; [[GroupList sharedGroupList] deleteGroup:fromIndex]; [[GroupList sharedGroupList] insertGroup:movedGroup atIndex:toIndex]; // Update the loadedGroupIndex pointer if (loadedGroupIndex < fromIndex & loadedGroupIndex >= toIndex) { loadedGroupIndex = loadedGroupIndex + 1; } else if (loadedGroupIndex > fromIndex & loadedGroupIndex < toIndex) { loadedGroupIndex = loadedGroupIndex - 1; } else if (loadedGroupIndex == fromIndex) { loadedGroupIndex = toIndex; } [movedGroup release]

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  • Resources for memory management in embedded application

    - by Elazar Leibovich
    How should I manage memory in my mission critical embedded application? I found some articles with google, but couldn't pinpoint a really useful practical guide. The DO-178b forbids dynamic memory allocations, but how will you manage the memory than? preallocate everything in advance and send a pointer to each function that needs allocation? Allocate it on the stack? Use a global static allocator (but then it's very similar to dynamic allocation)? Answers can be of the form of regular answer, reference to a resource, or reference to good opensource embedded system for example. clarification: The issue here is not whether or not memory management is availible for the embedded system. But what is a good design for an embedded system, to maximize reliability.

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  • Copying pointers in C++

    - by tunnuz
    Hello, I have a class A containing two pointers to objects of another class B. I want to initialize one pointer or the other depending on which one is passed to init(), which also takes other parameters. My situation is thus the following: class A { public: A(); init(int parameter, int otherParameter, B* toBeInitialized); protected: B* myB; B* myOtherB; }; Now my point is that I want to call init() as: init(640, 480, this->myB); or init(640, 480, this->myOtherB); Now, my init is implemented as: void init( int parameter, int otherParameter, B* toBeInitialized ) { toBeInitialized = someConstructorFunction(parameter, otherParameter); } The problem is that the two pointers are not initialized, I suspect that toBeInitialized is overwritten, but the original parameter is not modified. I am doing something wrong? Should I use references to pointers? Thank you Tommaso

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  • Performing time consuming operation on STL container within a lock

    - by Ashley
    I have an unordered_map of an unordered_map which stores a pointer of objects. The unordered map is being shared by multiple threads. I need to iterate through each object and perform some time consuming operation (like sending it through network etc) . How could I lock the multiple unordered_map so that it won't blocked for too long? typedef std::unordered_map<string, classA*>MAP1; typedef std::unordered_map<int, MAP1*>MAP2; MAP2 map2; pthread_mutex_lock(&mutexA) //how could I lock the maps? Could I reduce the lock granularity? for(MAP2::iterator it2 = map2.begin; it2 != map2.end; it2++) { for(MAP1::iterator it1 = *(it2->second).begin(); it1 != *(it2->second).end(); it1++) { //perform some time consuming operation on it1->second eg sendToNetwork(*(it1->second)); } } pthread_mutex_unlock(&mutexA)

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  • typedef resolution rule

    - by kumar_m_kiran
    Hi All, Can you Please tell me the resolution rule involved in resolving the meaning of the variable in a typedef. Any link related to the same will be very useful. Example #typedef string* pstring; const pstring parr; Here confusion arises whether const'ness is for pointer or the content. Now based on what thumb rule do can we start resolving the above interpretation of the pstring?. Smilarly, If I have a very complex typedef'ed variable, like #typedef void (func*)()(int), I should be able to resolve it using the thumb rule. Thanks in advance for your suggestions

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  • Can I use memcpy in C++ to copy classes that have no pointers or virtual functions

    - by Shane MacLaughlin
    Say I have a class, something like the following; class MyClass { public: MyClass(); int a,b,c; double x,y,z; }; #define PageSize 1000000 MyClass Array1[PageSize],Array2[PageSize]; If my class has not pointers or virtual methods, is it safe to use the following? memcpy(Array1,Array2,PageSize*sizeof(MyClass)); The reason I ask, is that I'm dealing with very large collections of paged data, as decribed here, where performance is critical, and memcpy offers significant performance advantages over iterative assignment. I suspect it should be ok, as the 'this' pointer is an implicit parameter rather than anything stored, but are there any other hidden nasties I should be aware of?

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  • Unexpected key-value behavior in a Core Data Context

    - by ????
    If I create an array of strings (via key-value coding) containing the names of a Managed Object entity's attributes which are stored in the App Delegate the first time, I get an array of NSStrings without any problems. If I subsequently make the same call later from the same entry point in code, that same collection becomes an array of NULL objects- even though nothing in the Core Data Context has changed. One unappealing work-around involves re-creating the string array every time, but I'm wondering if anyone has a guess as to what's happening behind the scenes. // Return an array of strings with the names of attributes the Activity entity - (NSArray *)activityAttributeNames { #pragma mark ALWAYS REFRESH THE ENTITY NAMES? //if (activityAttributeNames == nil) { // Create an entity pointer for Activity NSEntityDescription *entity = [NSEntityDescription entityForName:@"Activity" inManagedObjectContext:managedObjectContext]; NSArray *entityAttributeArray = [[NSArray alloc] initWithArray:[[entity attributesByName] allValues]]; // Extract the names of the attributes with Key-Value Coding activityAttributeNames = [entityAttributeArray valueForKeyPath:@"name"]; [entityAttributeArray release]; //} return activityAttributeNames; }

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  • What does this error mean when using OpenAL in the iPhone Simulator?

    - by mystify
    I'm getting this in the console, when creating my OpenAL Sources and Buffers: Cannot find executable for CFBundle/CFPlugIn 0xf530d0 </Library/Audio/Plug-Ins/HAL/Hear.plugin> (not loaded) 2010-05-05 17:11:13.934 Testproj[43173:207] Cannot find function pointer HearCFPlugInFactory for factory 5268FAAB-0147-4272-93FD-4D60A2433C1C in CFBundle/CFPlugIn 0xf430d0 </Library/Audio/Plug-Ins/HAL/Hear.plugin> (not loaded) However, the sounds play nicely. I think HAL is not available on the iPhone, it's just on Mac OS X, right? Do you guys also get that error in the simulator when using OpenAL?

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  • Help for CSS Menu Dropdown, FF OK and IE6 Problem

    - by Taruhku
    IE Problem, FF OK. Please help..???? Screen Shoot problem click here This is my CSS dolphincontainer { position:relative; height:56px; color:#E0E0E0; background:#143D55; width:100%; font-family:Tahoma; left: 0px; } dolphinnav {position:absolute;;height:33px;font-size:12px;font-weight:bold;background:#fff url(images/dolphin_bg.gif) repeat-x bottom left;padding:0 0 0 10px;width:975px;} dolphinnav ul {margin:0;padding:0;list-style-type:none;width:auto;float:left;} dolphinnav ul li {display:block;float:left;margin:0 1px;} dolphinnav ul li a {display:block;float:left;color:#001b2c;text-decoration:none;padding:0 0 0 10px;height:33px;} dolphinnav ul li a span {padding:12px 20px 0 0;height:21px;float:left;font-weight:bold;} dolphinnav ul li a:hover {color:#fff;background:transparent url(images/dolphin_bg-OVER.gif) repeat-x bottom left;} dolphinnav ul li a:hover span {display:block;width:auto;cursor:pointer;} dolphinnav ul li a.current,#dolphinnav ul li a.current:hover {color:#fff;background:#00517e url(images/dolphin_left-ON.gif) no-repeat top left;line-height:275%;} dolphinnav ul li a.current span {display:block;padding:0 20px 0 0;width:auto;background:#00517e url(images/dolphin_right-ON.gif) no-repeat top right;height:33px;} .tuckUp { display:block; width:90px; height:30px; overflow:hidden; cursor:pointer; } .pullDown { width:90px; height:56px; } .item a:link, .item a:visited { display:inline; float:left; background:#fff url(images/dolphin_bg.gif) repeat-x top left;padding:0 0 0 10px; text-align:left; color:#444; font-size:11px; font-weight:bold; text-decoration:none; line-height:25px; margin:0 5px 0px 0px; width:80px; } .item a:hover { display:inline; float:left; background:#39c; color:#FFF; text-decoration:none; text-align:left; font-size:11px; font-weight:700; font-weight:bold; line-height:25px; padding:0 0 0 10px; margin:0 5px 0px 0px; width:80px; } HTML: <div id="dolphincontainer"> <div id="dolphinnav"> <ul> <li><a href="index.php"><span>Home</span></a></li> <li><a href="chooseus.php"><span>Why Choose Us</span></a></li> <li><a href="peraturan.php"><span>Rules</span></a></li> <li class="tuckUp" onmousemove="this.className='pullDown'" onmouseout="this.className='tuckUp'"><a href="#"><span>Transaction</span></a> <div class="item"> <a href="drop1.php">Drop Down 1</a><br /> <a href="drop2.php">Drop Down 2</a></a><br /> <a href="drop3.php">Drop Down 3</a><br /> </div> </li> <li><a href="download.php"><span>Download</span></a></li> <li><a href="aboutus.php"><span>About Us</span></a></li> <li><a href="help.php" class="current"><span>Support</span></a></li> <li><a href="promo.php"><span><font color="#FF0000"><blink>PROMO</blink> </font></span></a></li> </ul> </div> </div>

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  • A programming language for teaching data structures and algorithms with? [closed]

    - by Andreas Grech
    Possible Duplicate: Choice of programming language for learning data structures and algorithms Teachers have different opinions on what programming language they would choose to teach data structures and algorithms with. Some would prefer a lower level language such as C because it allows the student to learn more about what goes on beyond the abstractions in terms of memory allocation and deallocation and pointers and pointer arithmetic. On the other hand, others would say that they would prefer a higher level language like Java because it allows the student to learn more about the concepts of the structures and the algorithm design rather than 'waste time' and fiddle around with memory segmentation faults and all the blunders that come with languages where memory management is manual. What is your take on this issue? And also, please post any references you may know of that also discuss this argument.

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  • Writing a PHP web crawler using cron

    - by Horse
    Hi all I have written myself a web crawler using simplehtmldom, and have got the crawl process working quite nicely. It crawls the start page, adds all links into a database table, sets a session pointer, and meta refreshes the page to carry onto the next page. That keeps going until it runs out of links That works fine however obviously the crawl time for larger websites is pretty tedious. I wanted to be able to speed things up a bit though, and possibly make it a cron job. Any ideas on making it as quick and efficient as possible other than setting the memory limit / execution time higher?

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  • Confused about "override" vs. "new" in C#

    - by iTayb
    I'm having the following classes: class Base { public virtual void Print() { Console.WriteLine("Base"); } } class Der1 : Base { public new virtual void Print() { Console.WriteLine("Der1"); } } class Der2 : Der1 { public override void Print() { Console.WriteLine("Der2"); } } This is my main method: Base b = new Der2(); Der1 d1 = new Der2(); Der2 d2 = new Der2(); b.Print(); d1.Print(); d2.Print(); The output is Base, Der2, Der2. As far as I know, Override won't let previous method to run, even if the pointer is pointing to them. So the first line should output Der2 as well. However Base came out. How is it possible? How the override didn't work there?

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  • What will be the setup process for website development?

    - by Vijay Shanker
    Hi, I want to create a simple site for my personal usage. And this only in python based technologies. So I want to get a expert oponian on this topic. What should i used as platform? I did a search for available options and found Django, grok, web2py and many more of these. Which one a novice use should use? If I choose to use only the basic python scripts then what option i have to work on? http://wiki.python.org/moin/WebBrowserProgramming. This link on python site confused me more, instead of solving my curiosity about the topic. Please give some pointer to accurate and easy to understand reading materials. I have got a idea of developing java based web applications using either spring-webmvc and struts. Can I relate Java process to python process for web development?

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  • Marshalling a C structure to C#

    - by Hilbert
    Hi, I don't know how to marshall this structure in Mono. typedef struct rib_struct { rib_used_t used; rib_status_t status; rib_role_t role; uint8_t conf; rib_dc_t *pending; pthread_mutex_t mutex; pthread_cond_t cond; rib_f_t *props; } rib_t; And for example, rib_dc_t is like: typedef struct rib_dc_struct { uint16_t id; uint8_t min_id; uint8_t conf; struct rib_dc_struct *next; } rib_dc_t; I don't know how to marshall the pthread structures. And the pointers... should I use IntPtr or a managed structures? How to mashall the pointer in the last struct to the struct itself? Thanks in adanvaced

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  • Send copy of class to view class so it can render him? ( iPhone )

    - by Johannes Jensen
    I'm making a game for the iPhone, and I have a class called Robot. Then I have a class called View, which renders everything. I want to send a copy of my Robot, which I defined in my ViewController, and I send it to gameView (which is View *gameView), like this: robot = [Robot new]; [gameView setRobot: [robot copy]]; I tried to make a copy but that didn't work, I could also do it with a pointer to Robot (&robot) but sometimes it just crashes ? I tried this in my View.h @interface definition: @property (copy) Robot* robot; but I get the error /RobotsAdventure/Classes/View.h:24: error: setter '-robot' argument type does not match property type :/ Help? I'm pretty new at this, heh.

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  • Avoiding Nested Blocks

    - by Helium3
    If there is a view controller that wants to execute a number of block based tasks one at a time, how can the control be given back to the view controller after a completion block has executed. Lets say ViewControllerOne wants to execute a number of tasks, each relying on the result of the previous one, how would this control be given back to the viewcontroller after each completion block has been executed? I started thinking about this and I was heading towards a deeply nested block pattern that will surely only cause confusion to whoever else reads or tests it. A task executes and the completion block returns the result or error which is needed by the next task, which has its own completion task, that the next task relies on and so forth. How can the control be managed in one place, the viewcontroller? Would the completion block just call the next function that handles the next task, using a pointer to the view controller?

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  • Trouble creating a makefile

    - by catia
    Hi everyone! I'm having some trouble making a Makefile. Write now I just compile everything every time. Although, the professor is ok with that, I do want to get it working faster and to avoid unnecessary compiling. Here's what I have. FILES= p6.cpp SetIter.cpp Node.cpp Set.cpp CFLAGS= -ansi -pendantic -Wall -Wextra CC= g++ MakePg6: p6.cpp SetIter.cpp Node.cpp Set.cpp $(CC) $(CFLAGS) $(FILES) -o pg6 Node.cpp - node class Set.cpp - uses nodes. Friend of Node. SetIter.cpp - gets a set and uses a pointer to iterator through I'm confused with some of the depencies arising from the friends thing and the point of lib.o being included in the Makefile as some sites have. Any help is greatly appreciated. Thanks in advance.

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  • one document.createElement, append it twice, only shows once

    - by Sirber
    I have a button I want to use in the beginning and the end of the page: var button_save = document.createElement('button'); $("#compteurs").append(button_save); [...] $("#compteurs").append(button_save); but it only appear at the end of the page. If I remove it from the bottom of the page, it appear at the begining of page. It's a kind of pointer. Is there a way to create the button only once and use it twice? Thanks!

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  • Manage bad_alloc exception in C++ construtor

    - by Jimmy zhang
    I have Java experience and recently am doing some C++ coding. My question is that if I have class A, in which I have to instantiate class B and class C as two of the member variables of A. If in the constructor of A, should I assume that allocations of class B and C never fail, and handle the bad allocation exception in the destructor of A? If I don't make that assumption, meaning that I add some try catch block to catch bad_alloc of class B and class C, then if the allocation exception occurs, should I do clean up in the constructor of A? What are the recommended practices? If "new" generates a bad allocation, what value does the pointer carry?

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  • delete & new in c++

    - by singh
    Hi This may be very simple question,But please help me. i wanted to know what exactly happens when i call new & delete , For example in below code char * ptr=new char [10]; delete [] ptr; call to new returns me memory address. Does it allocate exact 10 bytes on heap, Where information about size is stored.When i call delete on same pointer,i see in debugger that there are a lot of byte get changed before and after the 10 Bytes. Is there any header for each new which contain information about number of byte allocated by new. Thanks a lot

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  • Are self-described / auto-descriptive services loosely or tightly coupled in a SOA architecture ?

    - by snowflake
    I consider a self-described / auto-descriptive service as a good thing in a SOA architecture, since (almost) everything you know to call the service is present in the service contract (such a WSDL). Sample of a non self-described service for me is Facebook Query Language (FQL http://wiki.developers.facebook.com/index.php/FQL), or any web service exchanging XML flow in a one String parameter for then parsing XML and performing treatments. Last ones seem further more technically decoupled, since technically you can switch implementations without technical impact on the caller, handling compatibility between implementations/versions at a business level. On the other side, having no strong interface (diluted into the service and its version), make the service tightly coupled to the existing implementation (more difficulty to interchange the service and to ensure perfect compatibility). This question is related to http://stackoverflow.com/questions/2503071/how-to-implement-loose-coupling-with-a-soa-architecture So, are self-described / auto-descriptive services loosely or tightly coupled in a SOA architecture ? What are the impacts regarding ESBs ? Any pointer will be appreciated.

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  • Regular Expression to match unlimited number of options

    - by Pekka
    I want to be able to parse file paths like this one: /var/www/index.(htm|html|php|shtml) into an ordered array: array("htm", "html", "php", "shtml") and then produce a list of alternatives: /var/www/index.htm /var/www/index.html /var/www/index.php /var/www/index.shtml Right now, I have a preg_match statement that can split two alternatives: preg_match_all ("/\(([^)]*)\|([^)]*)\)/", $path_resource, $matches); Could somebody give me a pointer how to extend this to accept an unlimited number of alternatives (at least two)? Just regarding the regular expression, the rest I can deal with. The rule is: The list needs to start with a ( and close with a ) There must be one | in the list (i.e. at least two alternatives) Any other occurrence(s) of ( or ) are to remain untouched.

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  • How to convert from integer to unsigned char in C, given integers larger than 256?

    - by Alf_InPogform
    As part of my CS course I've been given some functions to use. One of these functions takes a pointer to unsigned chars to write some data to a file (I have to use this function, so I can't just make my own purpose built function that works differently BTW). I need to write an array of integers whose values can be up to 4095 using this function (that only takes unsigned chars). However am I right in thinking that an unsigned char can only have a max value of 256 because it is 1 byte long? I therefore need to use 4 unsigned chars for every integer? But casting doesn't seem to work with larger values for the integer. Does anyone have any idea how best to convert an array of integers to unsigned chars?

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  • Cannot implicitly convert type 'char*' to 'bool'

    - by neeraj
    i was trying to passing pointer value in the function , i really got stuck here I am a beginner , not getting what value should be put this is programme from the reference of the book "Cracking the coding interview " By Gayle Laakmann McDowell, class Program { unsafe void reverse(char *str) { char* end = str; char tmp; if (str) //Cannot implicitly convert type 'char*' to 'bool' { while(*end) //Cannot implicitly convert type 'char*' to 'bool' { ++end; } --end; while(str<end) { tmp = *str; *str+= *end; *end-= tmp; } } } public static void Main(string[] args) { } }

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  • small string optimization for vector?

    - by BuschnicK
    I know several (all?) STL implementations implement a "small string" optimization where instead of storing the usual 3 pointers for begin, end and capacity a string will store the actual character data in the memory used for the pointers if sizeof(characters) <= sizeof(pointers). I am in a situation where I have lots of small vectors with an element size <= sizeof(pointer). I cannot use fixed size arrays, since the vectors need to be able to resize dynamically and may potentially grow quite large. However, the median (not mean) size of the vectors will only be 4-12 bytes. So a "small string" optimization adapted to vectors would be quite useful to me. Does such a thing exist? I'm thinking about rolling my own by simply brute force converting a vector to a string, i.e. providing a vector interface to a string. Good idea?

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