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  • writing structs and classes to disk

    - by Phenom
    The following function writes a struct to a file. int btwrite(short rrn, BTPAGE *page_ptr) { long addr; addr = (long) rrn * (long) PAGESIZE + HEADERSIZE; lseek(btfd, addr, 0); return (write(btfd, page_ptr, PAGESIZE)); } The following is the struct. typedef struct { short keycount; /* number of keys in page */ int key[MAXKEYS]; /* the actual keys */ int value[MAXKEYS]; /* the actual values */ short child[MAXKEYS+1]; /* ptrs to rrns of descendants */ } BTPAGE; What would happen if I changed the struct to a class, would it still work the same? If I added class functions, would the size it takes up on disk increase?

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  • How to prevent inputting Russian characters in Word with a Word addin?

    - by Edwin
    Hi, Sorry for this vaguely described problem, but please look at the problem from the Win32 API's perspective. I'm writing a Word addin using Addin Express with Delphi, and I use some other 3rd party VCL's also, including virtual stringtree, TNT controls, etc. Now I cannot input Russian characters in Word anymore, but I can input English and Chinese.... Since it's a large project I don't know where to start finding the problem, would you give me some generic tips, I'll be appreciated that! Thank you, and have a nice day!

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  • Possible to exclude or reorder a column from `*` ?

    - by Earlz
    Is it possible to exclude a column from a select * from table statement with SQL Server? I have a need for this and this is my only option other than parsing a raw SQL string to get out the required field names (I really don't want to do that). Just to be bold. When the query is made I do not have access to the list of fields needed from the table but I do know which field I do not need. This is part of a complex multi-part query. Surely there must be some way even if it's "hackish" such as using table variables or views My other option is to reorder the columns. My problem is with ExecuteScalar SQL functions which get the first row and first column.

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  • Function to set an auth_token

    - by john mossel
    In my form I have a hidden field: <input type="hidden" name="auth_token" value="<?php echo $auth_token; ?>"> This value is also stored in a session and a variable: $_SESSION['auth_token'] = hash('sha256', rand() . time() . $_SERVER['HTTP_USER_AGENT']); # TODO: put this in a function $auth_token = $_SESSION['auth_token']; When the form is submitted the two values are compared. It's a basic form token. Should this be made into two functions or just one when refactored? set_form_token() and get_form_token(), get_form_token() returning the session value, then I can compare it in my main code. What is the proper way of doing this?

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  • I serialized a C++ object, how to allocate memory for it without knowing what type it is?

    - by Neo_b
    Hello, I have serialized a C++ object and I wish to allocate space for it, although I can't use the "new" operator, because I do not know the object's class. I tried using malloc(sizeof(object)), although trying to typecast the pointer to the type the serialized object is of, the program shut down. Where is the information about the object class stored? class object { public: virtual void somefunc(); int someint; }; class objectchild:public object { } object *o=(object*)malloc(sizeof(objectchild)); cout << int(dynamic_cast<objectchild*>(o)) << endl; This causes a program shutdown. Thank you in advance.

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  • from JS to iphone dev - what's the best language to start with?

    - by Enkai
    I am a total beginner and would like to eventually learn to develop for the iphone. I have just done a beginner's CS course where the language we learned was JavaScript. We studied basic concepts like: variables, arrays, loops (for,while,if,if..else..), properties and functions. I'm wondering if I am starting in the right/wrong place by following this book: Learn C on the Mac by Dave Mark? I have read a few chapters and am finding it a bit hard to get my head around the way that C works, for example the way that Strings are printed seems overly complicated as compared to JS. Do you think that JS was the wrong language to start off with and would I be better to go from JS straight to Objective-C rather than to C? I have tried to read up on previous threads on the merits/demerits of learning C first but haven't found any that relate JS to learning C/Obj C/ Cocoa. Any advice appreciated as I am very new to this. Thanks

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  • Per Process Memory Calculation Alogrithm in Linux (say kernel 2.6 and above)

    - by Vaibhav Singh
    How do you calculate the linux process's Acutal Memory Usage and Not Virtual Memory Usage through the information supplied by /proc//smaps or maps or status or stat. To be more precise I need the heap usage only. I need to do this on an PowerPc based embedded system and hence I do not have utilities like exmap, valgrind etc. I understand the concepts of shared/non shared memory. I have read through the other topics given in this forum about the same but they talk more using the tools mentioned. What I need is the native way of calculation done by the same tools so that I may write a shell script for the same.

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  • Is it good to use JQuery's validation plugin?

    - by kwokwai
    Hi all, I am learning JQuery, and I have checked out that JQUery has got a validation plugin. http://docs.jquery.com/Plugins/Validation#Validate_forms_like_you.27ve_never_been_validating_before.21 To use it, users have to include another script file in the Head tag in HTML. I am thinking if this will cause any code collisions to the codes in the validation plugin when more and more javascript files are included. Should I use JQuery to write myself new customed functions for checking data input from users or use the JQuery data validation plugin? Please advise.

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  • Implement abstract class as a local class? pros and cons

    - by sinec
    Hi, for some reason I'm thinking on implementing interface within a some function(method) as local class. Consider following: class A{ public: virtual void MethodToOverride() = 0; }; A * GetPtrToAImplementation(){ class B : public A { public: B(){} ~B(){} void MethodToOverride() { //do something } }; return static_cast<A *>(new B()); } int _tmain(int argc, _TCHAR* argv[]) { A * aInst = GetPtrToAImplementation(); aInst->MethodToOverride(); delete aInst; return 0; } the reason why I'm doing this are: I'm lazy to implement class (B) in separate files MethodToOverride just delegates call to other class Class B shouldn't be visible to other users no need to worry about deleting aInst since smart pointers are used in real implementation So my question is if I'm doing this right? Thanks in advance!

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  • What is an alternative to eval in this situation?

    - by CppLearner
    Many of my view functions do similar things. For the most part, they reverse to a different views upon clicking a button / a text link. So I wrote a helper function render_reverse def render_reverse(f, args): # args are all string type return eval('reverse(' + f + ', ' + args + ')' ) eval is a bad practice, and is pretty slow. It takes 3 seconds to start redirecting, whereas calling reverse directly takes less than 1 second to start redirecting. What alternative do I have? By the way, the function above doesn't work properly. I was modelling after this line (which works) eval('reverse("homepage", args=["abcdefg"])') Thanks.

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  • How to reference filtered ng-repeat items from a controller in AngularJS

    - by ParkerDigital
    I have some JSON data that is rendered out via the ng-repeat directive, and the results are then filtered via some checkboxes/drop-downs, and some custom filter functions in my controller. I now want to add a function to my controller that is triggered by an 'ng-change' on some of the checkboxes, that can reference the current list of items in my 'ng-repeat'. I realise I can reference these values from a custom filter, for example $scope.filterProvider = function(item), but this function is then called for each and every item in the ng-repeat, which isn't what I want - I want the function to just be called each time a checkbox is checked/unchecked, and I need that function to be able to reference the items in my ng-repeat...does that make sense to anyone?! And if so, does anyone know how I can do that? Thanks :-)

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  • Dynamic access to tables from another database inside an user function

    - by Alberto Martinez
    I have an user defined table function in SQL Server that aggregate data from several tables including a couple of tables of another database. That is done hardcoding the name of the database in the queries, but we want to make the database name configurable (because our databases usually share the server with the databases of other applications). I tried to construct a dynamic query string inside the function using the database name that is stored in a configuration table, but: When I tried exec(@sqlStatement) SQL Server said that execute string is not allowed inside a function. Then I tried exec sp_executesql @sqlStatement and the function was created, but when you execute it SQL Server says that inside a function you can only run extended functions and procedures. So the question is: is possible create a function or stored procedure that access a table in another database without having to recreate the function when the database name is different? TIA.

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  • Should I convert data arrays to objects in PHP in a CouchDB/Ajax app?

    - by karlthorwald
    I find myself converting between array and object all the time in PHP application that uses couchDB and Ajax. Of course I am also converting objects to JSON and back (for sometimes couchdb but mostly Ajax), but this is not so much disturbing my workflow. At the present I have php objects that are returned by the CouchDB modules I use and on the other hand I have the old habbit to return arrays like array("error"="not found","data"=$dataObj) from my functions. This leads to a mixed occurence of real php objects and nested arrays and I cast with (object) or (array) if necessary. The worst thing is that I know more or less by heart what a function returns, but not what type (array or object), so I often run into type errors. My plan is now to always cast arrays to objects before returning from a function. Of course this implies a lot of refactoring. Is this the right way to go? What about the conversion overhead? Other ideas or tips?

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  • Emacs and Long Shell Commands

    - by darrint
    Is there a way to run a shell command, have the output show up in a new buffer and have that output show up incrementally? Eshell and other emacs terminal emulators do a find job of this but I see no way to script them. What I'd like to do is write little elisp functions to do stuff like run unit tests, etc. and watch the output trickle into a buffer. The elisp function shell-command is close to what I want but it shows all the output at once when the process finishes.

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  • How to change the value of progressbar in C#?

    - by shekhar
    Hi, I want to add an progress bar into my C# based application. I would like to know what is the good way of updating its value at particular events? My problem is, I have single function in UI which does all the processing.This function in turn calls many more functions, creates objects, updates database, etc. (basically performs all the work) and returns values in an output file. I have access to that function only. So in this how to update the progressbar's value at the end of each step? What is the best practice for this kind of situation? What is the good way to keep UI logic and business logic seperate? I want to avoid writting progressbar related code in my library code. Please suggest some solution. Thanks and Regards,

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  • How to pass multiple params to function in python?

    - by user1322731
    I am implementing 8bit adder in python. Here is the adder function definition: def add8(a0,a1,a2,a3,a4,a5,a6,a7,b0,b1,b2,b3,b4,b5,b6,b7,c0): All function parameters are boolean. I have implemented function that converts int into binary: def intTObin8(num): bits = [False]*8 i = 7 while num >= 1: if num % 2 == 1: bits[i] = True else: bits[i] = False i = i - 1 num /= 2 print bits return [bits[x] for x in range(0,8)] I want this function to return 8 bits. And to use this two functions as follows: add8(intTObin8(1),intTObin8(1),0) So the question is: How to pass 8 parameters using one function?

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  • Composite pattern in C++ problem

    - by annouk
    Hello! I have to work with an application in C++ similar to a phone book: the class Agenda with an STL list of Contacts.Regarding the contacts hierarchy,there is a base-class named Contact(an abstract one),and the derived classes Friend and Acquaintance(the types of contact). These classes have,for instance, a virtual method called getName,which returns the name of the contact. Now I must implement the Composite pattern by adding another type of contact,Company(being derived from Contact),which also contains a collection of Contacts(an STL list as well),that can be either of the "leaf" type(Friends or Acquaintances),or they can be Companies as well. Therefore,Company is the Compound type. The question is: how and where can I implement an STL find_if to search the contact with a given name(via getName function or suggest me smth else) both among the "leaf"-type Contact and inside the Company collection? In other words,how do I traverse the tree in order to find possible matches there too,using an uniform function definition? I hope I was pretty clear...

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  • Add a custom class name to Wordpress body tag?

    - by Scott B
    I'd like to place a directive in my theme's functions.php file which appends a classname to the wordpress body tag. Is there a built-in API method for this? For example, my body tag code is... <body <?php if(function_exists("body_class") && !is_404()){body_class();} else echo 'class="page default"'?>> And it results in the following being written to the body tag (depending on the context in which the page is presented (page, post, logged-in, etc) <body class="home blog logged-in"> Depending on the child theme I'm using at the time, I want it to be... <body class="home blog logged-in mychildthemename">

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  • Why does the assignment operator return a value and not a reference?

    - by Nick Lowman
    I saw the example below explained on this site and thought both answers would be 20 and not the 10 that is returned. He wrote that both the comma and assignment returns a value, not a reference. I don't quite understand what that means. I understand it in relation to passing variables into functions or methods i.e primitive types are passed in by value and objects by reference but I'm not sure how it applies in this case. I also understand about context and the value of 'this' (after help from stackoverflow) but I thought in both cases I would still be invoking it as a method, foo.bar() which would mean foo is the context but it seems both result in a function call bar(). Why is that and what does it all mean? var x = 10; var foo = { x: 20, bar: function () {return this.x;} }; (foo.bar = foo.bar)();//returns 10 (foo.bar, foo.bar)();//returns 10

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  • Should I write small CGI scripts or a big, monolithic script?

    - by Space
    I am working on to create a web site to display some information about my system. This includes some graphs and some text information. For now I am creating different CGI scripts and calling them by creating links. A few days back one of my friends told me that instead of writting different CGI scripts, it's better to write single CGI script and create functions to call the part of code. I am confused. What do you prefer while creating a web site?

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  • Reserved Memory Addresses?

    - by Nate
    Is there a list of reserved memory addresses out there - a list of addresses that the memory of a user-space program could never be allocated to? I realize this is most likely per-OS or per-architecture, but I was hoping someone might know some of the more common OSes and Arches. I could only dig one up for a few versions of windows: for windows NT,2k and XP that would be: 0x00000000 - 0x0000ffff - lowest page is protected to simplify debugging 0x00001000 - 0x7ffeffff - memory area for your application 0x7fff0000 - 0x7fffffff - protected area to keep memory-functions from damaging the following part 0x80000000 - 0xffffffff - memory where the system including drivers and so on is located Anyone know about for Linux, or BSD (or anything else, for that matter)?

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  • On which Windows versions and configurations does my C++ app run?

    - by saas
    I've built a C++ application using MSVC 2010, default compile settings (note: Using "Multithreaded" instead of "Multithreaded DLL" to avoid the Microsoft C++ runtime being needed). I used only the STL and a few, old functions from the Win32 API (Windows.h). Where will my app run? (98-7?) Can the be any differences on how my app works on different PCs? As said: It's only a simple console app. I'd be glad if you could add some additional information if you have it!

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  • Can single-buffer blocking WSASend deliver partial data?

    - by CodeAngry
    I've pretty much always used send() with sockets and now I'm moving onto the WSA functions. With send(), I have a sendall() helper that ensured all data is delivered even if it didn't happen in one try and a partial send occurred on first call. So, instead of learning the hard way or over-complicating code when I don't have to, decided to ask you: Can a blocking WSASend() send partial data or does it send everything before it returns or fails? Or should I check the bytes sent vs. expected to send and keep at it until everything is delivered? ANSWER: Overlapped WSASend() does not send partial data but if it does, it means the connection has terminated. I've never encountered the case yet.

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  • Is PThread a good choice for multi-platorm C/C++ multi-threading program?

    - by RogerV
    Been doing mostly Java and smattering of .NET for last five years and haven't written any significant C or C++ during that time. So have been away from that scene for a while. If I want to write a C or C++ program today that does some multi-threading and is source code portable across Windows, Mac OS X, and Linux/Unix - is PThread a good choice? The C or C++ code won't be doing any GUI, so won't need to worry with any of that. For the Windows platform, I don't want to bring a lot of Unix baggage, though, in terms of unix emulation runtime libraries. Would prefer a PThread API for Windows that is a thin-as-possible wrapper over existing Windows threading APIs. ADDENDUM EDIT: Am leaning toward going with boost:thread - I also want to be able to use C++ try/catch exception handling too. And even though my program will be rather minimal and not particularly OOPish, I like to encapsulate using class and namespace - as opposed to C disembodied functions.

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  • What is the smallest Windows header I can #include to define DWORD?

    - by j_random_hacker
    I have a small header file of my own which declares a couple of functions, one of which has a return type of DWORD. I'm reluctant to drag in windows.h just to get the official definition of this type since that file is huge, and my header will be used in a number of source modules that don't otherwise need it. Of course, in practice I know that DWORD is just unsigned int, but I'd prefer the more hygienic approach of including an official header file if possible. On this page it says that DWORD is defined in windef.h, but unfortunately including just this small file directly leads to compilation errors -- apparently it expects to be included by other headers. (Also, the fact that my file is a header file also means I can't just declare WIN32_LEAN_AND_MEAN, since the source file that #includes my file might need this to be left undefined.) Any ideas? I know it's not the end of the world -- I can just continue to #include <windows.h> -- but thought someone might have a better idea!

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