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  • Qt: default value of variable in class

    - by Martin
    When creating my own class in Qt I would like my variables in the class to have a standard/default value if I haven't set them to anything. It would be perfect if this was possible to set in the h-file so I don't have to do it in each instance method of my class. You can see what I want to do in the code below. In the example myBool would have the value of false and myInt the value of 0 when the object have been created. Is this possible at all? In myclass.h: class MyClass { Q_OBJECT public: MyClass(); ~MyClass(); bool myBool = false; //I want to set myBool and myInt to a default/standard value int myInt = 0; };

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  • Multiple calls to /dev/stdin using python subprocess (*nix)

    - by Alex Leach
    Hi, I have a python subprocess call which I would like to link up to three pipes (two standard in and one standard out). I know that there is only one /dev/stdin, but there's all those other devices in /dev I don't know about, and don't know of any python os, sys or subprocess modules that will utilise them in a manner which allows me to give the device path to subprocess.Popen. The reason I ask is because I would like to pipe information from a mysql database or tar archive rather than a directory structure I currently have which has 28,000 directories in. The directory names alone uses a LOT of space! The alternative is to tar / gunzip the entire directory structure and manoeuvre through the compressed archive. With either solution, mysql or tar, I would still like to have two pipes into subprocess.Popen and one out, so that I can bypass the HDD. Any need for an example??

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  • I would like to learn C++, what is the first step ?

    - by Cesar
    My actual experience comes from PHP and Delphi(Borland) and recently also from Obj-C (iPhone sdk). In the past I also used Java, Python, VB 6 and some other scripting language. I would like to learn C++ because i need a standard tool for write compiled applications with good performance but i have no idea about witch environment i have to choose (Ex: Borland, Microsoft, Eclipse+MinGW, ...). Based those parameters: Most useful more opensource project or work requests Most standard not a proprietary versions Biggest community documentation, manuals, tutorials, forums... Better IDE add-ons, highlight, debug, cross platform, autocomplete... Easy setup A simple setup, to focus on learning the basics Actually I'm on OSX but I can use a VM if needed. Advices about tutorial or books are welcome. I hope it's not too generic as question.

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  • MySQL Query WHERE Including CASE or IF?

    - by handfix
    Strange problem. My Query looks like SELECT DISTINCT ID, `etcetc`, `if/elses over muliple joined tables` FROM table1 AS `t1` # some joins, eventually unrelated in that context WHERE # some standard where statements, they work/ CASE WHEN `t1`.`field` = "foo" THEN (`t1`.`anOtherField` != 123 AND `t1`.`anOtherField` != 456 AND `t1`.`anOtherOtherField` != "some String") WHEN `t1`.`field` = "bar" THEN `t1`.`aSecondOtherField` != 12345 END #ORDER BY CASE etc. Standard Stuff Apperantly MySQL returns a wrong rowcount and I think my problem is in the logic of the WHERE ... CASE statement. Maybe with the brackets? Maybe I should go for operator OR and not AND? Should my the second WHEN include brackets also, even when I only compare one field? Should I use IF and not CASE? Basically I want to exclude some rows with specific values IF theres a specific value in field foo or bar I would try that all out, but it takes a huge amount of time to complete that query... :(

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  • How Iostream file is located in computer by c++ code during execution

    - by user3702024
    i want to know that in a c++ code during execution how iostream file is founded. we write #include in c++ program and i know about #include which is a preprocessor directive to load files and is a file name but i don't know that how that file is located. i have some questions in my mind... Is Standard library present in compiler which we are using? Is that file is present in standard library or in our computer? Can we give directory path to locate the file through c++ code if yes then how?

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  • If I don't odr-use a variable, can I have multiple definitions of it across translation units?

    - by sftrabbit
    The standard seems to imply that there is no restriction on the number of definitions of a variable if it is not odr-used (§3.2/3): Every program shall contain exactly one definition of every non-inline function or variable that is odr-used in that program; no diagnostic required. It does say that any variable can't be defined multiple times within a translation unit (§3.2/1): No translation unit shall contain more than one definition of any variable, function, class type, enumeration type, or template. But I can't find a restriction for non-odr-used variables across the entire program. So why can't I compile something like the following: // other.cpp int x; // main.cpp int x; int main() {} Compiling and linking these files with g++ 4.6.3, I get a linker error for multiple definition of 'x'. To be honest, I expect this, but since x is not odr-used anywhere (as far as I can tell), I can't see how the standard restricts this. Or is it undefined behaviour?

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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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  • What are the advantages and disadvantages of plug-in based architecture?

    - by RP
    I want to do the architectural design for a software that can be used integrate various third party software’s (executable) under one platform. Standard project types will be added to the platform by default. The project type defines the way in which the different software will be executed and their input and output files. The user can customize the available standard project type and that will be added to the platform as new project type which defines new custom execution flow. Also it should support easy extension and customization of the features. I read that plug-in based architecture supports both. What are the advantages and disadvantages of plug-in based architecture? Do we have any better architecture which can be used for this kind of scenario? Thanks in advance:)

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  • F#: Can't hide a type abbreviation in a signature? Why not?

    - by Nels Beckman
    In F#, I'd like to have what I see as a fairly standard Abstract Datatype: // in ADT.fsi module ADT type my_Type // in ADT.fs module ADT type my_Type = int In other words, code inside the module knows that my_Type is an int, but code outside does not. However, F# seems to have a restriction where type abbreviations specifically cannot be hidden by a signature. This code gives a compiler error, and the restriction is described here. If my_Type were instead a discriminated union, then there is no compiler error. My question is, why the restriction? I seem to remember being able to do this in SML and Ocaml, and furthermore, isn't this a pretty standard thing to do when creating an abstract datatype? Thanks

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  • Windows service - supplying arguments in "path to executable"

    - by Jono
    I cannot figure out how to pass (constant) arguments into my Windows service when it is started. I'm using the standard .NET classes like ServiceBase to implement (and ServiceProcessInstaller and ServiceInstaller to install) my service. On the general tab of a Windows Service properties dialog box (once installed), there's a "Path to executable" in which I can see that some of the standard Windows services have command line arguments specified. System.ServiceProcess.ServiceBase.OnStart takes string[] args, which I presume would enable these arguments to be accessed from within .NET code. Are there some properties on ServiceProcessInstaller or ServiceInstaller that I can set to allow me to pass startup arguments to my own service, or does anyone know how it's supposed to be done?

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  • Are there any ASP.NET MVC Real Time View Editors?

    - by BenMaddox
    I'm looking for a tool and I'm not even sure of the proper name. Please be patient with me as I explain. I'm doing a lot of html/mvc 2 work. Using the standard MVC 2 view engine, I would like to have an editor that shows real time changes in the browser. If I re-arrange div elements containing standard HTML and some server side components, I would like the browser to update without a manual refresh. Are there any tools that are currently available that would meet that requirement?

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  • Would this union work if char had stricter alignment requirements than int?

    - by paxdiablo
    Recently I came across the following snippet, which is an attempt to ensure all bytes of i (nad no more) are accessible as individual elements of c: union { int i; char c[sizeof(int)]; }; Now this seems a good idea, but I wonder if the standard allows for the case where the alignment requirements for char are more restrictive than that for int. In other words, is it possible to have a four-byte int which is required to be aligned on a four-byte boundary with a one-byte char (it is one byte, by definition, see below) required to be aligned on a sixteen-byte boundary? And would this stuff up the use of the union above? Two things to note. I'm talking specifically about what the standard allows here, not what a sane implementor/architecture would provide. I'm using the term "byte" in the ISO C sense, where it's the width of a char, not necessarily 8 bits.

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  • How to track dealloc of an abstract object class (NSMutable...)

    - by Thomas Tempelmann
    I have a bug in my code caused by a premature freeing of a ObjC object. I seem not to be able to find it by just looking at my code. There's usually a simple trick to track the dealloc to any class: Implement dealloc, and set a breakpoint. This even usually works with standard objects, by subclassing them and making sure I instantiate the subclass instead of the standard class. However, this does not seem to work with NSMutableArray, and probably neither with similar NSMutable... classes. Some explanations for this can be found here: link text Any other ideas how to track the dealloc invocation of a particular class or object so that I can see the call stack? It's probably possible with DTrace. Any pointers without having to read the entire dtrace docs first?

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  • Formating phone numbers

    - by Sven
    Our customers often fill out "incorrect" formated phone-numbers. Do anyone know if there is any lib or standard to convert numbers into a more international style? This is a Swedish example but we have customers around the globe and i don't what to manually handle implementations for everyone. input often is like this: 0555 11122 and the wanted result is something like this: +46(0)555-11122 I can do the formating myself but different countries have different variations and systems so a C/Java/C# lib or a standard method to handle this would be great.

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  • How do I calculate the offset, in hours, of a given timezone from UTC in ruby?

    - by esilver
    I need to calculate the offset, in hours, of a given timezone from UTC in Ruby. This line of code had been working for me, or so I thought: offset_in_hours = (TZInfo::Timezone.get(self.timezone).current_period.offset.utc_offset).to_f / 3600.0 But, it turns out that was returning to me the Standard Offset, not the DST offset. So for example, assume self.timezone = "America/New_York" If I run the above line, offset_in_hours = -5, not -4 as it should, given that the date today is April 1, 2012. Can anyone advise me how to calculate offset_in_hours from UTC given a valid string TimeZone in Ruby that accounts for both standard time and daylight savings? Thanks!

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  • Access message inbox without Content UrI (content//:sms)

    - by Nishant Kumar
    Hi, I want to access the messages stored in inbox through my android project. I have tried the method of forming URI for sms (content://sms/ inbox) and then quering it for various parametres. But I cannot find any documentation for reading inbox sms in the standard Android Developr Docs. It was mentioned at various websites that this content has been removed from the standard sdk. The application may not support higher version of android. So, how can I create an apllication to read sms from inbox that is reliable in furture version of android. Please help !!

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  • Is allocating a dynamic array without specifying size well formed code?

    - by Als
    The following simple program snippet gives compilation errorswith gcc-4.3.4. Program: int main() { char *ptr = new char[10]; char *ptr1 = new char[]; return 0; } Compilation errors: prog.cpp: In function ‘int main()’: prog.cpp:4: error: expected primary-expression before ‘]’ token prog.cpp:3: warning: unused variable ‘ptr’ prog.cpp:4: warning: unused variable ‘ptr1’ But the same compiles cleanly with MSVC without any diagnostic message. So my question is: Does the Standard allow an new [] to be called without specifying the size? Or this a bug in MSVC? Can someone provide a reference from the standard which will conclusively say that the above code example is ill-formed or well-formed? I have had a look at: 5.3.4 New [expr.new] & 18.4.1.2 Array forms [lib.new.delete.array] but couldnt find any conclusive evidence about the behavior.

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  • Is there a unified way to know if a node is visible or not?

    - by zneak
    Hello guys, I'd like to be able to know if a node is visible and rendered on screen. As far as I know, there are at least 3 standard and easy ways of making HTML nodes not visible: Setting opacity: 0; Setting display: none; Setting visibility: hidden. I could check for just these three, but I'm afraid people can get creative when it comes to ways of hiding contents: Sending the element offscreen using negative margins; Using a width or height of 0 and hiding overflow; many more I trust people to have developed. So I was wondering if there is a standard way of determining if a node is rendered to the screen. I'm pretty sure all major browsers determine it for themselves to accelerate drawing, so maybe it's somehow exposed.

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  • What is a simple C library for a set of integer sets?

    - by conradlee
    I've got to modify a C program and I need to include a set of unsigned integer sets. That is, I have millions of sets of integers (each of these integer sets contains between 3 and 100 integers), and I need to store these in some structure, lets call it the directory, that can in logarithmic time tell me whether a given integer set already exists in the directory. The only operations that need to be defined on the directory is lookup and insert. This would be easy in languages with built-in support for useful data structures, but I'm a foreigner to C and looking around on Google did (surprisingly) not answer my question satisfactorily. This project looks about right: http://uthash.sourceforge.net/ but I would need to come up with my own hash key generator. This is a standard, simple problem, so I hope there is a standard and simple solution.

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  • What is the purpose of using -pedantic in GCC/G++ compiler?

    - by huahsin68
    Hi, -ansi: tells the compiler to implement the ANSI language option. This turns off certain "features" of GCC which are incompatible with the ANSI standard. -pedantic: used in conjunction with -ansi, this tells the compiler to be adhere strictly to the ANSI standard, rejecting any code which is not compliant. Text above is extract from this note. First thing first, what is the purpose of usage of -pedantic and -ansi option with GCC/G++ compiler, I couldn't understand the above description. Can anyone tell me the circumstances of using the above two options? When should I use it? Is it important one? THanks @!

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  • Preg_replace regex, newlines, connection resets

    - by bob_the_destroyer
    I have mixed html, custom code, and regular text I need to examine and change frequently on several, long wiki pages. I'm working with a proprietary wiki-like application and have no control over how the application functions or validates user input. The layout of pages that users add must follow a very specific standard layout and always include very specific text in only certain places - a standard which frequently changes. If users add pages that are so far out of the standard, they will be deleted. The fact that all this is obviously a complete waste of time when alternative platforms to do exactly what's needed here exist is already understood. I've built a PHP based API to automate this post-validation and frequent restandardization process for me. I've been able set up regex patterns to handle all this mixed text, and they all work fine for handling single lines. The problem I have is this: Poorly formed regex against long text with line breaks can lead to unexpected results, such as connection resets. I have no access to server-side logs to troubleshoot. How do I overcome this? This is just one example of what I currently have: {column} and {section} tags I'm searching for below can have any number of attributes, and wrap any text. {section} may or may not exist and may or may not be one or more lines under {column}, but it has to be wrapped inside {column}. {column} itself may or may not exist, and if it doesn't, I don't care. I want to grab the inner section contents and wrap it in an html div tag. I can't recall the exact pattern I'm using offhand at the moment, but it's close enough... $pattern = "/\{column:id=summary([|]?([a-zA-Z0-9-_ ]+[:][a-zA-Z0-9-_ ]+[ ]?))\}(.*)({section([|]([a-zA-Z0-9-_ ]+[:][a-zA-Z0-9-_ ]+[ ]?))\}(.*)\{section\}(.*))?{column\}/s"; $replacement = "{html}<div id='summary'$7</div{html}"; $text = preg_replace($pattern, $replacement, $subject); Handling the {column} and {section} attributes and passing only valid HTML parameters to the new html div or a subtext of it is itself a challenge, but my main focus above right now is getting that (.*) value within {section} above without causing a connection reset. Any pointers?

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  • Complicated Order By Clause?

    - by Todd
    Hi. I need to do what to me is an advanced sort. I have this two tables: Table: Fruit fruitid | received | basketid 1 20100310 2 2 20091205 3 3 20100220 1 4 20091129 2 Table: Basket id | name 1 Big Discounts 2 Premium Fruit 3 Standard Produce I'm not even sure I can plainly state how I want to sort (which is probably a big part of the reason I can't seem to write code to do it, lol). I do a join query and need to sort so everything is organized by basketid. The basketid that has the oldest fruit.received date comes first, then the other rows with the same basketid by date asc, then the basketid with the next earliest fruit.received date followed by the other rows with the same basketid, and so on. So the output would look like this: Fruitid | Received | Basket 4 20091129 Premuim Fruit 1 20100310 Premuim Fruit 2 20091205 Standard Produce 3 20100220 Big Discounts Any ideas how to accomplish this in a single execution?

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