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  • Custom setter methods in Core-Data

    - by andrewebling
    I need to write a custom setter method for a field (we'll call it foo) in my subclass of NSManagedObject. foo is defined in the data model and Xcode has autogenerated @property and @dynamic fields in the .h and .m files respectively. If I write my setter like this: - (void)setFoo: (NSObject *)inFoo { [super setFoo: inFoo]; [self updateStuff]; } then I get a compiler warning on the call to super. Alternatively, if I do this: - (void)setFoo: (NSObject *)inFoo { [super setValue: inFoo forKey: inFoo]; [self updateStuff]; } then I end up in an infinite loop. So what's the correct approach to write a custom setter for a subclass of NSManagedObject?

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  • How to parse (infinite) nested object notation?

    - by kyogron
    I am currently breaking my head about transforming this object hash: "food": { "healthy": { "fruits": ['apples', 'bananas', 'oranges'], "vegetables": ['salad', 'onions'] }, "unhealthy": { "fastFood": ['burgers', 'chicken', 'pizza'] } } to something like this: food:healthy:fruits:apples food:healthy:fruits:bananas food:healthy:fruits:oranges food:healthy:vegetables:salad food:healthy:vegetables:onions food:unhealthy:fastFood:burgers food:unhealthy:fastFood:chicken food:unhealthy:fastFood:pizza In theory it actually is just looping through the object while keeping track of the path and the end result. Unfortunately I do not know how I could loop down till I have done all nested. var path; var pointer; function loop(obj) { for (var propertyName in obj) { path = propertyName; pointer = obj[propertyName]; if (pointer typeof === 'object') { loop(pointer); } else { break; } } }; function parse(object) { var collection = []; }; There are two issues which play each out: If I use recurse programming it looses the state of the properties which are already parsed. If I do not use it I cannot parse infinite. Is there some idea how to handle this? Regards

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  • MinGW screw up with COLORREF and RGB

    - by kjoppy
    I am trying to build a 3rd party open source project using MinGW. One of the dependencies is wxWidgets. When I try to make the project from MSYS I get a compiler error from /MinGW/msys/1.0/local/include/wx-2.8/wx/msw/private.h In function 'COLORREF wxColourToRGB(const wxColour&)': error: cannot convert 'RGB' to 'COLORREF {aka long unsigned in}' in return This is somewhat odd given that, according to Microsoft the RGB macro returns a COLORREF. In fact, looking in H:\MinGW\include I find wingdi.h with the following code #define RGB(r,g,b) ((COLORREF)((BYTE)(r)|((BYTE)(g) << 8)|((BYTE)(b) << 16))) What sort of thing would cause this error? Is there some way I can check to see if COLORREF and RGB are being included from wingdi.h and not somewhere else? Is that even worth checking? Specifications GCC version 4.7.2 wxWidgets version 2.8.12 (I'm new to C++ and MinGW specifically but generally computer and programming literate)

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  • Appropriate uses of Monad `fail` vs. MonadPlus `mzero`

    - by jberryman
    This is a question that has come up several times for me in the design code, especially libraries. There seems to be some interest in it so I thought it might make a good community wiki. The fail method in Monad is considered by some to be a wart; a somewhat arbitrary addition to the class that does not come from the original category theory. But of course in the current state of things, many Monad types have logical and useful fail instances. The MonadPlus class is a sub-class of Monad that provides an mzero method which logically encapsulates the idea of failure in a monad. So a library designer who wants to write some monadic code that does some sort of failure handling can choose to make his code use the fail method in Monad or restrict his code to the MonadPlus class, just so that he can feel good about using mzero, even though he doesn't care about the monoidal combining mplus operation at all. Some discussions on this subject are in this wiki page about proposals to reform the MonadPlus class. So I guess I have one specific question: What monad instances, if any, have a natural fail method, but cannot be instances of MonadPlus because they have no logical implementation for mplus? But I'm mostly interested in a discussion about this subject. Thanks! EDIT: One final thought occured to me. I recently learned (even though it's right there in the docs for fail) that monadic "do" notation is desugared in such a way that pattern match failures, as in (x:xs) <- return [] call the monad's fail. It seems like the language designers must have been strongly influenced by the prospect of some automatic failure handling built in to haskell's syntax in their inclusion of fail in Monad.

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  • How we run a .NET 32-bit application in a 64-bit Windows server?

    - by Geo
    We are installing a third party application in one of our 64-bit Windows servers. This application apparently was build with the compiler option set to choose the platform at run time. When we run the application it gives us an error: System.BadImageFormatException: is not a valid Win32 application. I have seen in MSDN forums that in order to fix this error I have to build the application set to 32-bit, and that way it will run fine on a 64-bit server. I check on other StackOverflow links Other Posts. How to get around this situation? For everyone that wants to know more information: The application is running fine in a 32-bit test server. IIS version 6 using SQL Server Express 2005 On the Web Service Extension there are both Framework64\v2.0.50727\aspnet_isapi.dll and Framework\v2.0.50727\aspnet_isapi.dll

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  • How to define and use a local variable in aspx page?

    - by Bruskvilla
    Hello how can I define a local variable in aspx page. I just did the below code it gives errors. I'm new please help. Thanks. <% Devamsizlik.Models.DevamDurumu obj; % <% foreach (var item in Model){ %> .....blabla <% obj = item; %> <%} %>//end of foreach < p <%: Html.ActionLink("Create New", "DevamsizEkle", new { ogrId = obj.devamOgrenciID }, new { subeId = obj.devamsizlikSubeID })% < / p > ....< /p cause a compilation error Compiler Error Message: CS0165: Use of unassigned local variable 'obj'

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  • SIFR, JAVASCRIPT & PHP - How to apply SIFR to dynamically loaded content.

    - by user311039
    Well here's the problem: I have a PHP index page which uses show/hide layers javascript. I am using the on menu.click function to show and hide content relevant to each menu. On.click all divs are hidden except the content for that menu item , which fades in. The content relating to each menu item are displayed within separate DIVS. The property is applied to all the text within all the divs. See: http://jobe-group.com/jobeco/uk/2010live/dynamic/content/index.php# The trouble is that SIFR only appears to be applied to the displayed on.load when the page is first loaded. When this is hidden and the other s shown through the "show" function they load in classic CSS fonts without the SIFR applied. Is this unavoidable with the SIFR setup. Or am I not calling the divs properly. I have set the SIFR to apply to the selector and indeed it works fine on the for the displayed on load. It doesn't work for the within other . In theory I would think its possible to load the SIFR on all divs on page.load even if those divs are presently visibility:hidden. What's the verdict on this? Hope someone can help. Cheers, John

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  • Is there a good collection library for C-language?

    - by matti
    We have to maintain and even develop C-code of our legacy system. Is there good collection library that would support Java/C# (new versions) style collections. Hashtable, HashSet, etc. Of course without objects, but with structs. The HashTable key limitations to "strings" and ints is not a problem. It wouldn't be bad if it's free even for commercial use. I'm back to C from C# and I must say i'm depressed using our own libraries and the language in general. We're using VS2005 and MS C-compiler if that has nothing to do with anything. Thanks & BR -Matti

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  • Function template accepting nothing less than a bidirectional iterator or a pointer

    - by san
    I need a function template that accepts two iterators that could be pointers. If the two arguments are random_access iterators I want the return type to be an object of std::iterator<random_access_iterator_tag, ...> type else a std::iterator<bidirectional_iterator_tag, ...> type. I also want the code to refuse compilation if the arguments are neither a bidirectional iterator, nor a pointer. I cannot have dependency on third party libraries e.g. Boost Could you help me with the signature of this function so that it accepts bidirectional iterators as well as pointers, but not say input_iterator, output_iterator, forward_iterators. One partial solution I can think of is the following template<class T> T foo( T iter1, T iter2) { const T tmp1 = reverse_iterator<T>(iter1); const T tmp2 = reverse_iterator<T>(iter2); // do something } The idea is that if it is not bidirectional the compiler will not let me construct a reverse_iterator from it.

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  • Connect to a website via HTTP in C

    - by sfactor
    i have a C code that parses a file and generates another file for the processed data. i now need to send these files to a web server (website). i guess there way is to do a HTTP POST. but i have never done this in c (Linux gcc compiler in ubuntu). Does anyone know how to do this. i need to a starting point as i have no clue of doing this in C. i also need to be able to authenticate with the website.

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  • C++ - defining static const integer members in class definition

    - by HighCommander4
    My understanding is that C++ allows static const members to be defined inside a class so long as it's an integer type. Why, then, does the following code give me a linker error? #include <algorithm> #include <iostream> class test { public: static const int N = 10; }; int main() { std::cout << test::N << "\n"; std::min(9, test::N); } The error I get is: test.cpp:(.text+0x130): undefined reference to `test::N' collect2: ld returned 1 exit status Interestingly, if I comment out the call to std::min, the code compiles and links just fine (even though test::N is also referenced on the previous line). Any idea as to what's going on? My compiler is gcc 4.4 on Linux.

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  • HOW TO understand the programmming of operation system..!!!

    - by piemesons
    Hello, I want to learn the operating system. How it works. I dont want to make my own operating system. I just want to learn how it works. As i can find out source code of any open source OS. But how to start. Like stating from the first elementary kernal(what ever it is). Some body suggested me try to implement linux from scratch.etc etc.Please guide me in a proper way. i want to know about the proper path to follow. I am ready to invest three four years just to understand the basics. I am having good fundamentals of c c++,php, Oops, compiler design

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  • Generics Type issue

    - by JohnJohnGa
    ArrayList<Integer> arrI = new ArrayList<Integer>(); ArrayList arrO = arrI; // Warning /* It is ok to add a String as it is an ArrayList of Objects but the JVM will know the real type, arrO is an arrayList of Integer... */ arrO.add("Hello"); /* How I can get a String in an ArrayList<Integer> ?? Even if the compiler told me that I will get an Integer! */ System.out.println(arrI.get(0)); Anybody can explain what's happening here?

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  • Using typedefs (or #defines) on built in types - any sensible reason?

    - by jb
    Well I'm doing some Java - C integration, and throught C library werid type mappings are used (theres more of them;)): #define CHAR char /* 8 bit signed int */ #define SHORT short /* 16 bit signed int */ #define INT int /* "natural" length signed int */ #define LONG long /* 32 bit signed int */ typedef unsigned char BYTE; /* 8 bit unsigned int */ typedef unsigned char UCHAR; /* 8 bit unsigned int */ typedef unsigned short USHORT; /* 16 bit unsigned int */ typedef unsigned int UINT; /* "natural" length unsigned int*/ Is there any legitimate reason not to use them? It's not like char is going to be redefined anytime soon. I can think of: Writing platform/compiler portable code (size of type is underspecified in C/C++) Saving space and time on embedded systems - if you loop over array shorter than 255 on 8bit microprocessor writing: for(uint8_t ii = 0; ii < len; ii++) will give meaureable speedup.

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  • Design pattern: polymorphisim for list of objects

    - by ziang
    Suppose I have a class A, and A1, A2 inherits from A. There are 2 functions: List<A1> getListA1(){...} List<A2> getListA2(){...} Now I want to do something similar to both A1 and A2 in another function public void process(List<A>){...} If I want to pass the instance of either ListA1 or ListA2, of course the types doesn't match because the compiler doesn't allow the coercion from List< A1 to List< A. I can't do something like this: List<A1> listA1 = getListA1(); List<A> newList = (List<A>)listA1; //this is not allowed. So what is the best approach to the process()? Is there any way to do it in a universal way rather than write the similar code to both List and List?

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  • floating constants in C

    - by Daziplqa
    Hi floks, I have a question concerning floating constants in C. In Java, the default type of floating point constants in double, so the following will causes a compilation error in java: float f = 100.0; // we either need to uses type case operator or put f at the end of the number constant. This is because the default floating-point constants are of type double and casting from double to float without type cast operator is an error, so we need either add a type case operator or put f at the end of the number. So, Why in C this doesn't produce an error, Is it because the default floating-point constants are of type float, or because the compiler do an implicit down-cast conversion (that doesn't requires type case operator in C)????

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  • When will YOU adopt C++0x?

    - by HighCommander4
    I'm particularly looking for input from managers of ongoing C++ projects: Have you already adopted C++0x? If so, what has your experience been like? If you haven't adopted C++0x yet, are you planning to? If so, what is your timeline (in rough terms)? Are there any obstacles that are holding you back from adopting C++0x? Perhaps you are waiting for your favourite compiler or IDE to catch up? For managers of open source projects: are you afraid that adopting C++0x will mean less developers who are willing/able to contribute because they don't know the new features? Or, on the other hand, do you think most developers have been eagerly awaiting C++0x, and and will jump at the opportunity to use it? Do you think C++0x is stable enough to be adopted by a large project?

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  • An easy way to replace fread()'s with reading from a byte array?

    - by Sam Washburn
    I have a piece of code that needs to be run from a restricted environment that doesn't allow stdio (Flash's Alchemy compiler). The code uses standard fopen/fread functions and I need to convert it to read from a char* array. Any ideas on how to best approach this? Does a wrapper exist or some library that would help? Thanks! EDIT: I should also mention that it's reading in structs. Like this: fread(&myStruct, 1, sizeof(myStruct), f);

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  • How should open source libraries be used on Windows?

    - by Jason Owen
    There are many open-source libraries that can be compiled with Visual Studio. I'm porting a program from Linux to Windows, but it depends on a number of libraries. I don't know what the best practices regarding libraries are on Windows. On Linux, these libraries are typically part of the distribution. To use sqlite on Debian, for example, you need only to install libsqlite3-dev and the include files and libraries (both static and dynamic) are automatically installed and available to your program. If you need a different version than your distribution supplies, you can compile it in your home directory, install it to ~/include and ~/lib, and set the appropriate environment variables so that your compiler includes those directories in its search path. What is the best way to use libraries that are distributed as source on Windows? If I link dynamically rather than statically, is there an easy way to copy required DLLs into the output directory to ease redistribution (assuming license requirements are met)?

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  • How to include header files in Visual Studio 2008?

    - by Sergio
    I am currently trying to compile a simple program that includes two header files. I see them in the Solution Explorer, where I included them through "include existing files". However, when I run my program it get the following error. fatal error C1083: Cannot open include file: 'FileWrite.h': No such file or directory. THe problem is that I see the file included in the Header's folder and in the code I have written: #include "FileWrite.h" and then the rest of the program code. Is there something else needed to do so that the compiler can see the header file and link it to the .cpp file I'm trying to compile?

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  • Avoiding repeated subqueries when 'WITH' is unavailable

    - by EloquentGeek
    MySQL v5.0.58. Tables, with foreign key constraints etc and other non-relevant details omitted for brevity: CREATE TABLE `fixture` ( `id` int(11) NOT NULL auto_increment, `competition_id` int(11) NOT NULL, `name` varchar(50) NOT NULL, `scheduled` datetime default NULL, `played` datetime default NULL, PRIMARY KEY (`id`) ); CREATE TABLE `result` ( `id` int(11) NOT NULL auto_increment, `fixture_id` int(11) NOT NULL, `team_id` int(11) NOT NULL, `score` int(11) NOT NULL, `place` int(11) NOT NULL, PRIMARY KEY (`id`) ); CREATE TABLE `team` ( `id` int(11) NOT NULL auto_increment, `name` varchar(50) NOT NULL, PRIMARY KEY (`id`) ); Where: A draw will set result.place to 0 result.place will otherwise contain an integer representing first place, second place, and so on The task is to return a string describing the most recently played result in a given competition for a given team. The format should be "def Team X,Team Y" if the given team was victorious, "lost to Team X" if the given team lost, and "drew with Team X" if there was a draw. And yes, in theory there could be more than two teams per fixture (though 1 v 1 will be the most common case). This works, but feels really inefficient: SELECT CONCAT( (SELECT CASE `result`.`place` WHEN 0 THEN "drew with" WHEN 1 THEN "def" ELSE "lost to" END FROM `result` WHERE `result`.`fixture_id` = (SELECT `fixture`.`id` FROM `fixture` LEFT JOIN `result` ON `result`.`fixture_id` = `fixture`.`id` WHERE `fixture`.`competition_id` = 2 AND `result`.`team_id` = 1 ORDER BY `fixture`.`played` DESC LIMIT 1) AND `result`.`team_id` = 1), ' ', (SELECT GROUP_CONCAT(`team`.`name`) FROM `fixture` LEFT JOIN `result` ON `result`.`fixture_id` = `fixture`.`id` LEFT JOIN `team` ON `result`.`team_id` = `team`.`id` WHERE `fixture`.`id` = (SELECT `fixture`.`id` FROM `fixture` LEFT JOIN `result` ON `result`.`fixture_id` = `fixture`.`id` WHERE `fixture`.`competition_id` = 2 AND `result`.`team_id` = 1 ORDER BY `fixture`.`played` DESC LIMIT 1) AND `team`.`id` != 1) ) Have I missed something really obvious, or should I simply not try to do this in one query? Or does the current difficulty reflect a poor table design?

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  • Is it possible to come over the time out issue for a function call in C#?

    - by infant programmer
    In my program I call a method xslTransform.Load(strXmlQueryTransformPath, xslSettings, new XmlUrlResolver()); The problem I am facing is: sometimes this function doesn't execute well within the time. Sometimes compiler raises the time out issue after a long time of trial.. which inturn causes this part of application to shut. That is what I want to avoid. So if it exceeds certain time say 10 seconds I need to recall the method. Is it possible to add some code lines adjacent to this, which can meet the requirement?

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  • The implicit function __strcpy_chk() call

    - by Summer_More_More_Tea
    Hi everyone: I'm now performing a stack buffer overflow attack test on my own PC( Ubuntu 9.10, gcc-4.4.1 ) based on the article http://www.tenouk.com/Bufferoverflowc/Bufferoverflow4.html. Yet I haven't achieved the goal. Each time a segfault is thrown accompanied with some error informaiton. I compile the source code, and wanna get further information using objdump. Function __strcpy_chk is invoked in the assembly code dumped out, and it's said that "The __strcpy_chk() function is not in the source standard; it is only in the binary standard." Does this the mechanism a compiler employed to protect runtime stack? To finish my test, how can I bypass the protection? Regards.

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  • Fix DB duplicate entries (MySQL bug)

    - by Silence
    I'm using MySQL 4.1. Some tables have duplicates entries that go against the constraints. When I try to group rows, MySQL doesn't recognise the rows as being similar. Example: Table A has a column "Name" with the Unique proprety. The table contains one row with the name 'Hach?' and one row with the same name but a square at the end instead of the '?' (which I can't reproduce in this textfield) A "Group by" on these 2 rows return 2 separate rows This cause several problems including the fact that I can't export and reimport the database. On reimporting an error mentions that a Insert has failed because it violates a constraint. In theory I could try to import, wait for the first error, fix the import script and the original DB, and repeat. In pratice, that would take forever. Is there a way to list all the anomalies or force the database to recheck constraints (and list all the values/rows that go against them) ? I can supply the .MYD file if it can be helpful.

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  • C static variables and intialization

    - by yCalleecharan
    Hi, If I have a global static variable x like in this code #include <stdio.h> #include <stdio.h> static int x; int main(void) { DO SOMETHING WITH x HERE x++; } What will be difference if I opted to initialize x to a value first say as in static int x = 0; before entering "main"? In my first case where I didn't assign a value to x, does the compiler implicitly know that x is to be set to zero as it's a static variable? I heard that we can do this with static variables. Thanks a lot...

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