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  • iphone @property(retain), init(), and standards

    - by inyourcorner
    I'm new to the memory management of the iphone and had a question about standards/correctness. My header file declares: IBOutlet UITabBarController *tabBarController; @property (nonatomic, retain) UITabBarController *tabBarController; In my init() code I was doing something like the following: self.tabBarController = [[UITabBarController alloc] init]; [tabBarController release]; NSLog(@"Retain count of tbc: %d",[tabBarController retainCount]); to get the retain count back to one. Is this correct from a standardization point of view? It just looked a bit different to me, but again I'm new to this. Thanks

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  • Address of array vs. address of array[0] - C language

    - by user324994
    My question is why does the address of an array differ from the address of its first position? I'm trying to write my own malloc, but to start out I'm just allocating a chunk of memory and playing around with the addresses. My code looks roughly like this: #define BUFF_SIZE 1024 static char *mallocbuff; int main(){ mallocbuff = malloc(BUFF_SIZE); printf("The address of mallocbuff is %d\n", &mallocbuff); printf("The address of mallocbuff[0] is %d\n", &mallocbuff[0]); } &mallocbuff is the same address every time I run it. &mallocbuff[0] is some random address every time. I was expecting the addresses to match each other. Can anyone explain why this isn't the case?

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  • What is the difference between the * and the & operators in c programming?

    - by Wesley
    I am just making sure I understand this concept correctly. With the * operator, I make a new variable, which is allocated a place in memory. So as to not unnecessarily duplicate variables and their values, the & operator is used in passing values to methods and such and it actually points to the original instance of the variable, as opposed to making new copies...Is that right? It is obviously a shallow understanding, but I just want to make sure I am not getting them mixed up. Thanks!

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  • Simple integer encryption

    - by tloflin
    Is there a simple algorithm to encrypt integers? That is, a function E(i,k) that accepts an n-bit integer and a key (of any type) and produces another, unrelated n-bit integer that, when fed into a second function D(i,k) (along with the key) produces the original integer? Obviously there are some simple reversible operations you can perform, but they all seem to produce clearly related outputs (e.g. consecutive inputs lead to consecutive outputs). Also, of course, there are cryptographically strong standard algorithms, but they don't produce small enough outputs (e.g. 32-bit). I know any 32-bit cryptography can be brute-forced, but I'm not looking for something cryptographically strong, just something that looks random. Theoretically speaking it should be possible; after all, I could just create a dictionary by randomly pairing every integer. But I was hoping for something a little less memory-intensive.

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  • About first-,second- and third-class value

    - by forest58
    First-class value can be passed as an argument returned from a subroutine assigned into a variable. Second-class value just can be passed as an argument. Third-class value even can't be passed as an argument. Why should these things defined like that? As I understand, "can be passed as an argument" means it can be pushed into the runtime stack;"can be assigned into a variable" means it can be moved into a different location of the memory; "can be returned from a subroutine" almost has the same meaning of "can be assigned into a variable" since the returned value always be put into a known address, so first class value is totally "movable" or "dynamic",second class value is half "movable" , and third class value is just "static", such as labels in C/C++ which just can be addressed by goto statement, and you can't do nothing with that address except "goto" .Does My understanding make any sense? or what do these three kinds of values mean exactly?

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  • Is there a way to launch an aggressive and complete garbage collection in Java?

    - by Gnoupi
    For memory optimization reasons, I'm launching myself the garbage collector during profiling, to check if objects are correctly cleaned after disposing of them. The call to garbage collector is not enough, though, and it seems that there is no guarantee of what it will clean. Is there a way to call it, to be sure it will recover as much as it can, in profiling conditions (this would have no point in production, of course)? Or is "calling it several times" the only way to be "almost sure"? Or did I simply misunderstand something about the Garbage Collector?

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  • Possible to implement an IsViewPortVisible dependencyproperty for an item in an ItemsControl?

    - by Matt H.
    I need to enable/disable spell checking in a richtextbox in an ItemsControl, based on whether the RichTextBox is visible in the ItemsControl's Scrollviewer. I think the route is to implement an IsViewPortVisible dependency property and wire an event handler for a changed event... I found this article that describes the lengthy process for determining if an item is in the viewport: http://social.msdn.microsoft.com/Forums/en/wpf/thread/e6ccfec3-3dc0-4702-9d0d-1cfa55ecfc90 Any ideas on where to start? I'm familiar with implementing my own dependency property for the sake of simple bindings (integers, strings, etc...). I have no idea how to undergo something like this though) This is the end result I'm hoping for: <DataTemplate> <Grid> ...Stuff in the Grid <local:CustomRichTextBox SpellCheck.IsEnabled={Binding RelativeSource={RelativeSource Self}, Path=IsViewPortVisible}/> </Grid> </DataTemplate> Help will be EXTREMELY appreciated... you'll be saving me about 500MB in memory consumption while the program is running!!!! :)

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  • Extracting a reference from a c++ vector

    - by Archanimus
    Hello folks, I have a vector< vector< vector< int and I would like to extract from it a vector< vector< int to process it individually. The problem is that when I write : myMatrix = myCube[anIndex]; the matrix is copied but I only want a reference in order to save memory. Can you please help me out ? Thanks a lot!

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  • Fast, cross-platform timer?

    - by dsimcha
    I'm looking to improve the D garbage collector by adding some heuristics to avoid garbage collection runs that are unlikely to result in significant freeing. One heuristic I'd like to add is that GC should not be run more than once per X amount of time (maybe once per second or so). To do this I need a timer with the following properties: It must be able to grab the correct time with minimal overhead. Calling core.stdc.time takes an amount of time roughly equivalent to a small memory allocation, so it's not a good option. Ideally, should be cross-platform (both OS and CPU), for maintenance simplicity. Super high resolution isn't terribly important. If the times are accurate to maybe 1/4 of a second, that's good enough. Must work in a multithreaded/multi-CPU context. The x86 rdtsc instruction won't work.

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  • Load python module not from a file

    - by user575061
    Hello, I've got some python code in a library that attempts to load a simple value from a module that will exist for the applications that use this library from somemodule import simplevalue Normally, the application that uses the library will have the module file and everything works fine. However, in the unit tests for this library the module does not exist. I know that I can create a temporary file and add that file to my path at runtime, but I was curious if there is a way in python to load something in to memory that would allow the above import to work. This is more of a curiosity, saying "add the module to your test path" is not helpful :P

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  • How does the WP7 Pivot control dynamically load pivot items?

    - by mztan
    IIRC, the Pivot control only loads a child PivotItem if it is the currently shown child. I would then guess that the previously seen child is also somehow unloaded, presumably still stored in memory, but hidden from the UI. What I'm wondering is, how does the Pivot control dynamically load/unload a child control, and can that behavior be imitated within a custom UserControl? As for unloading, is it as simple as collapsing the previous child's visibility, or is something trickier going on? That is to say, supposing I use my own UserControl like: <my:CustomUserControl> <TextBlock x:Name="_textBlock" Text="wait for it ..." /> </my:CustomUserControl> Normally, the child TextBlock is instantiated when the surrounding PhoneApplicationPage is instantiated, via InitializeComponent and all that. Is there any way to postpone this behavior and load the child programmatically?

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  • Can I make a pointer to the code, and pass to the next instruction?

    - by drigoSkalWalker
    Like this link http://gcc.gnu.org/onlinedocs/gcc-3.3.1/gcc/Labels-as-Values.html I can get the memory address of an label, so if I declare a label, get your address, and add your address, i will pass to next instruction? some ilustration int main () { void *ptr; label: instruction 1; instruction 2; ptr = &&label; // So if I do it... ptr = ptr + 1; // I will get the instruction 2 correct?? Thanks for all answers.

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  • Unity and web service

    - by zachary
    I had this awesome idea... but I am afraid maybe it is actually a bad idea.... we use unity for dependency injection. I make interfaces from my web services using partial classes for the purpose of mocking and web services.... What I want to do is put my web services into unity and get them via dependency injection... What do you think? Is there too much overhead somewhere? Memory leaks? Is this a bad idea?

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  • Execute hidden process in Windows Mobile 6

    - by kingo
    Hello everyone, I have a test.exe that need to be called in my main application and run in the background (my main app must stay on top). I know we can use CreateProcess with hide option in MFC, but in windows mobile library the startupinfo is unavailable. So does anyone have an idea how to do ? Besides, is there any way that we can load and execute test.exe in the memory so that user can't see it in the running program dropdown list? Thank you very much.

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  • Aptana Studio is opening but not ever closing a python.exe process

    - by SC Ghost
    I am developing a small testing website using Django 1.2 in Aptana Studio build 2.0.4.1268158907. I have a Django project that I test by running the command "runserver 8001" on my project. This command runs the project on a small server that comes with Django. However the problem arises that every time I run this command Aptana opens two instances of the process "python.exe". Upon terminating the command only one of these instances is ended. The other process continues to run and use memory. My server is not online, and the process doesn't seem to do anything that I can find. This happens every time i run the runserver command on my project and therefore more and more python.exe instances will open up through my development period. Any help discovering either the purpose of this extra python.exe or a way to prevent it from opening would be much appreciated.

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  • How to get "printer ready bytes" from a source in c#?

    - by luis_villase
    Hey everyone! I'm in a bit of trouble here, hoping you can help a fellow programmer out. I have an application that receives a pointer to raw bytes (plus length and stuff) and sends said raw data to a printer. This is important, I have no choice but to use this method to get any printing done. If I send a raw string, it will print with no problem. However, I need to be able to print formatted text, images, etc. So the thing is... I would like to be able to get printer ready bytes from a given source (maybe a pdf, or html, does not matter as long as it contains formatted text and/or images). It would be like "splitting" the print command like so: a) Open file and read data b) Load printer data into memory c) Send bytes to printer Obviously, I've got a) and c) covered, it's b) the one that's breaking my head. Any thoughts? Thanks in advance for your help.

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  • Fastmm4 and leaking handles...

    - by JD
    Hi to all, I have just used FastMM4 to detect leaks. I did not realise our application was using a DLL which was leaking event handles and so I fixed any leaks reported by FastMM4 but not the handles as it was not reported. My questions are, would have FastMM4 have reported the leaking event handles? Would this require me to rebuild the dlls with FastMM4 included? I also heard someone mention ShareMM, do I need to add that? I am using Delphi2007, which I think is using the borland memory manager and if so, should I replace it with the fastMM4 one? What are the steps to do that? Sorry for asking so many questions, I am looking at delphi after a few years of doing .net development. JD.

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  • Using cachedwithin attibute inside cfquery

    - by Jason
    When you use the cachedwithin attribute in a cfquery how does it store the query in memory. Does it store it by only the name you assign to the query? For example, if on my index page I cache a query for an hour and name it getPeople will a query with the same name on a different page (or the same page for that matter) use the cached results or does it use some better logic to decide if it is the same query? Also, if there is a variable in your query does the cache take into account the value of the variable?

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  • how to update off screen pivot item

    - by Yama moto
    I want to have a pivot with many PivotItems. However, doing so will impact memory. So I bind pivot to my ViewModel, which has 3 item, and pivot will generate 3 PivotItems. My ViewModel is of type ObservableCollection and my item does implement INotifyPropertyChanged. This works fine. But when I update my ViewModel, only the current PivotItem, and the right PivotItem is updated. The left PivotItem, which is off screen, is not updated. You can see it when you drag pivot to the left. How to fix this? Or WP7 doesnot update off screen PivotItem ?

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  • how to save image and data locally in iphone device

    - by MaheshBabu
    Hi folks, I am getting image and some details from .net web server. I need to store these details in iphone device memory(not in sdcard),Because I need to connect web services only one time,that is at installing my app. From Next time onwards i need to get data from device. I have some knowledge in java,In java i use files to store image and Hash table to store details. How can i done this in iphone. can any one pls help me. Thank u in advance.

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  • Differences between extension methods in C#3 & 4

    - by Buh Buh
    I think I remember reading a long time ago that in C#3 extension methods could only be applied to primitive types and interfaces; and that in C#4 they could be used to extend any type. This doesn't seam to match up with what I am seeing now and I am finding it difficult to find this documented. Is there any truth to this or did my memory make it all up? What are the rules relating to which types can be extended? Are there any differences between C# 3 and 4?

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  • Reason for different segments in Linux on x86

    - by anjruu
    Hey all, So, I know that Linux uses four default segments for an x86 processor (kernel code, kernel data, user code, user data), but they all have the same base and limit (0x00000000 and 0xfffff), meaning each segment maps to the same set of linear addresses. Given this, why even have user/kernel segments? I understand why there should be separate segments for code and data (just due to how the x86 processor deals with the cs and ds registers), but why not have a single code segment and a single data segment? Memory protection is done through paging, and the user and kernel segments map to the same linear addresses anyway. Thanks! anjruu

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  • How to access controls collection of dynamically loaded aspx page?

    - by Naasir
    Let's say I have two webforms, A.aspx and B.aspx, where B.aspx contains some simple web controls such as a textbox and a button. I'm trying to do the following: When A.aspx is requested, I want to dynamically call and load B.aspx into memory and output details of all the controls contained in B.aspx. Here is what I tried in the codebehind for A.aspx: var compiledType = BuildManager.GetCompiledType("~/b.aspx"); if (compiledType != null) { var pageB = (Page)Activator.CreateInstance(compiledType); } foreach (var control in pageB.Controls) { //output some details for each control, like it's name and type... } When I try the code above, the controls collection for pageB is always empty. Any ideas on how I can get this to work? Some other important details: both webforms utilize a master page (so the web controls in b.aspx are actually placed within a "content" tag) I've also tried using BuildManager.CreateInstanceFromVirtualPath. No luck.

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  • What is the result of "new int[ 0 ]"? [closed]

    - by ArunSaha
    Possible Duplicates: What does zero-sized array allocation do/mean? C++ new int[0] — will it allocate memory? int * p; p = new int[ 0 ]; What is the expected outcome when new is called for zero number of elements? Is the outcome defined or undefined? Further, is it okay to call delete [] p; on that pointer? What is the intuition/analogy to this situation of pointer to an array of zero elements? Thanks in advance. Regards, Arun

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  • Which destructor is called when in C++?

    - by BastiBechtold
    I am hunting memory leaks in a program. I narrowed it down to some destructors not being called. However, I can't figure out why: class CMain : public CList { public: CMain(); virtual ~CMain(); ... } class CList : public CProc { public: CList(); virtual ~CList(); ... } CMain gets deallocated just fine, but ~CList() is never called. All parent classes of CList have virtual destructors, too. Do you have any hints about why the destructor for CList is never called?

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