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• matrix = *((fxMatrix*)&d3dMatrix); //Evil?

  - by Xilliah

  I've been using matrix = *((fxMatrix*)&d3dMatrix); for quite a while. It worked fine until my screen turned black and received a bucket of frustration on my desk. fxMatrix contains 4 fxVectors. fxVector used to be 16 bytes, but now it was suddenly 20. This was because it inherited fxStreamable, which added the vTable. So one solution is of course just to not inherit fxStreamable, and leave a comment saying that it must always be 16 bytes and never more. Another solution would be to make conversion functions, and copy the matrix completely. This makes it more secure, but has an impact on the performance. I suppose this is the best idea. Another solution is to not convert at all, and stick to D3DXMATRIX, but this makes the engine inconsistent and I personally really dislike this idea. What is your opinion?

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• Lots of pointer casts in QGraphicsView framework and performance

  - by kleimola

  Since most of the convenience functions of QGraphicsScene and QGraphicsItem (such as items(), collidingItems(), childItems() etc.) return a QList you're forced to do lots of qgraphicsitem_cast or static_cast and QGraphicsItem::Type() checks to get hold of the actual items when you have lots of different type of items in the scene. I thought doing lots of subclass casts were not a desirable coding style, but I guess in this case there are no other viable way, or is there? QList<QGraphicsItem *> itemsHit = someItem->collidingItems(Qt::IntersectsItemShape); foreach (QGraphicsItem *item, itemsHit) { if (item->type() == QGraphicsEllipseItem::type()) { QGraphicsEllipseItem *ellipse = qgraphicsitem_cast<QGraphicsEllipseItem *>(item); // do something } else if (item->type() == MyItemSubclass::type()) { MyItemSubClass *myItem = qgraphicsitem_cast<MyItemSubClass *>(item); // do something } // etc } The above qgraphicsitem_cast could be replaced by static_cast since correct type is already verified. When doing lots of these all the time (very dynamic scene), will the numerous casting affect performance beyond the normal if-else evaluation?

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• hierarchical data from self referencing table in tree form

  - by Beta033

  It looks like this has been asked and answered in all the simple cases, excluding the one that I'm having trouble with. I've tried using a recursive CTE to generate this; however maybe a cursor would be better? Or maybe a set of recursive functions will do the trick? Can this be done in a cte? consider the following table PrimaryKey ParentKey 1 NULL 2 1 3 6 4 7 5 2 6 1 7 NULL should yield PK 1 -2 --5 -6 --3 7 -4 where the number of - marks equal the depth, my primary difficulty is the ordering.

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• Bootstrap jquery methods Magento's prototype lib

  - by user1722527

  Wonder if anyone has had this issue. I've integrated Bootstrap nicely into a Magento theme I'm building, all good. That is, until I try using the accordian functions. There seems to be an issue with the code finding the Prototype Libs Methods instead of jQuery's. I've tried the usual fixes, $ - jQuery and no conflict but it only works when I disable the prototype lib - which obviously is not good. Anyone out there come across this and can advise me on a work round? At the moment I'm resigned to using Scriptaculous for the accordian.

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• VB.NET logical expression evaluator

  - by Tim

  I need to test a logical expression held in a string to see if it evaluate to TRUE or FALSE.(the strig is built dynamically) For example the resulting string may contain "'dog'<'cat' OR (14 AND 4<6)". There are no variables in the string, it will logically evaluate. It will only contain simple operators = < < = <= and AND , OR and Open and Close Brackets, string constants and numbers. (converted to correct syntax && || etc.) I currently acheive this by creating a jscipt function and compiling it into a .dll. I then reference the .dll in my VB.NET project. class ExpressionEvaluator { function Evaluate(Expression : String) { return eval(Expression); } } Is there a simpler method using built in .NET functions or Lamdba expressions.

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• Infor PM (Business Intelligence solution)

  - by Andrew

  We are currently implementing the commercial Infor PM (Performance Management) package as a business intelligence tool. Infor PM website It is apparently used by over 1,000 companies around the world, but I have found scant information about it on the net except for what's on their own website. It covers the whole range of data warehousing and BI functions with: an OLAP environment an ETL tool a report writer (called Application Studio) an add-on to Excel to connect to the data in the cubes through a pivot table etc Does anyone have any experience with using this package? How does it compare to the big players in BI (Cognos, Microsoft SSAS, Business Objects, etc). Any pitfalls I should know about? On the other hand, does it do anything better than its competitors?

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• C++: Switching from MSVC to G++: Global Variables

  - by feed the fire

  I recently switched to Linux and wanted to compile my Visual Studio 2010 C++ source code, which uses only the STL, on G++. My Linux machine currently isn't available but I can try to tell you what is going on, first: As I try to compile my project, all global variables I use in main and which perfectly work on MSVC result in myGlobalVar is not defined in this scope errors. My project is built nearly the same as the example below: // myclass.h class myClass { // .... }; extern myClass globalInstance; // myclass.cpp #include "myclass.h" // myClass functions located here myClass globalInstance; // main.cpp #include "myclass.h" int main( ) { // Accessing globalInstance results in an error: Not defined in this scope } What am I doing wrong? Where are the differences between G++ and MSVC in terms of global variables?

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• Sum of distinc rows after a 1-many table join

  - by Lock

  I have 2 tables that I am joining. Table 1 has 1-many relationship with table 2. That is, table 2 can return multiple rows for a single row of table 1. Because of this, the records of table 1 is duplicated for as many rows as are on table 2.. which is expected. Now, I have a sum on one of the columns from table 1, but because of the multiple rows that get returned on the join, the sum is obviously multiplying. Is there a way to get this number back to its original number? I tried dividing by the count of rows from table 2 but this didnt quite give me the expected result. Are there any analytical functions that could do this? I almost want something like "if this row has not yet been counted in the sum, add it to the sum"

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• C++ conversion operator between types in other libraries

  - by Dave

  For convenience, I'd like to be able to cast between two types defined in other libraries. (Specifically, QString from the Qt library and UnicodeString from the ICU library.) Right now, I have created utility functions in a project namespace: namespace MyProject { const icu_44::UnicodeString ToUnicodeString(const QString& value); const QString ToQString(const icu_44::UnicodeString& value); } That's all well and good, but I'm wondering if there's a more elegant way. Ideally, I'd like to be able to convert between them using a cast operator. I do, however, want to retain the explicit nature of the conversion. An implicit conversion should not be possible. Is there a more elegant way to achieve this without modifying the source code of the libraries? Some operator overload syntax, perhaps?

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• When are C++ macros beneficial?

  - by Motti

  The C preprocessor is justifiably feared and shunned by the C++ community. In-lined functions, consts and templates are usually a safer and superior alternative to a #define. The following macro: #define SUCCEEDED(hr) ((HRESULT)(hr) >= 0) is in no way superior to the type safe: inline bool succeeded(int hr) { return hr >= 0; } But macros do have their place, please list the uses you find for macros that you can't do without the preprocessor. Please put each use-cases in a seperate answer so it can be voted up and if you know of how to achieve one of the answers without the preprosessor point out how in that answer's comments.

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• C++ code generation for repeted task

  - by sateesh

  Hi, I have something like below which will get repeated many times based on the function that get called for e.g acceptfunction() { inserter["quantity"] = sdd.getfloat(quantity); inserter["prodtype"] = sdd.getstring(prodtype); : : so on } Like accept above there are 20 more functions(reject,cancel etc) which will do the similar thing.But the parameteres they insert can differ based on function called. How can I automate this kind of code.So that I dont need to write new function from scratch.Basically what I need is if i provide parametres like ("quantity",prodtype) through some text file or xml, it should generate the required function with the input parametres. Is this task can be handled through C++ tempalte Meta programming or someother code generation tool will help me to do this?

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• How to combine two arrays of same length to one array with two fields (not append/merge)

  - by Raj

  Say, I have an array with months $months = array('Jan', 'Feb', 'Mar'...'Dec'); And another, with days (say, for year 2010) $mdays = array(31, 28, 31...31); I want to merge/combine these two arrays, into an array like this: $monthdetails[0] = ('month' => 'Jan', 'days' => 31) $monthdetails[1] = ('month' => 'Feb', 'days' => 28) ... $monthdetails[11] = ('month' => 'Dec', 'days' => 31) I can loop through both the arrays and fill the $monthdetails. I want to know whether there are any functions/easier way for achieving the same result. Thanks! Raj

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• Unexpected result from reduce function

  - by StackedCrooked

  I would like to get the smallest element from a vector. For this I use combine the reduce and min functions. However, when providing my own implementation of min I get unexpected results: user=> (reduce (fn [x y] (< x y) x y) [1 2 3 2 1 0 1 2]) 2 user=> (reduce min [1 2 3 2 1 0 1 2 3]) 0 The reduce with standard min returns 0 as expected. However, when I provide my own implementation it returns 2. What am I doing wrong?

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• Implementing N-tire structure in .net

  - by pravakar

  Hi friends, my requirement is suppose i have three classes namely Employee, Customer and Department where Employee contains attributes i.e. id,name,dept and Customer class contains Id,name and Department class contains i.e. id and name. Now all these three class has common function i.e. create, update and delete. This functions i want to implement using interface. So can any one suugest me to perform these things in n-tier architecture.

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• Indexing XMLType columns

  - by Chris

  Hello, I am working with a XMLType and currently experiencing significant performance issues and would like to incorporate indexing to the column type. Currently I am taking the approach of using the XMLTable() and XQuery functions to create a virtual table. I would like to use this Virtual Table to create a function based index on the table containing the XMLType, but I am receiving this error: Error report: SQL Error: ORA-00907: missing right parenthesis 00907. 00000 - "missing right parenthesis" *Cause: *Action: This is the index.. any assistance would be greatly appreciated. CREATE INDEX indx_medicinalproduct ON d.ProductName XMLTable('for $i at $a in /safetyreport/patient//drug for $j in $i/medicinalproduct return element r { $i/medicinalproduct }' PASSING s.safetyreport COLUMNS ProductName varchar2(70) PATH 'medicinalproduct') d;

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• Syncronizing indices of function pointer table to table contents

  - by Thomas Matthews

  In the embedded system I'm working on, we are using a table of function pointers to support proprietary Dynamic Libraries. We have a header file that uses named constants (#define) for the function pointer indices. These values are used in calculating the location in the table of the function's address. Example: *(export_table.c)* // Assume each function in the table has an associated declaration typedef void (*Function_Ptr)(void); Function_Ptr Export_Function_Table[] = { 0, Print, Read, Write, Process, }; Here is the header file: *export_table.h* #define ID_PRINT_FUNCTION 1 #define ID_READ_FUNCTION 2 #define ID_WRITE_FUNCTION 3 #define ID_PROCESS_FUNCTION 4 I'm looking for a scheme to define the named constants in terms of their location in the array so that when the order of the functions changes, the constants will also change. (Also, I would like the compiler or preprocessor to calculate the indices to avoid human mistakes like typeo's.)

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• Is there a way to read 10000 lines from a file in python?

  - by windsound

  I am relatively new in python, was working on C a lot. Since I was seeing so many new functions in python that I do not know, I was wondering if there is a function that can request 10000 lines from a file in python. Something like this is what I expect if that kind of function exist: lines = get_10000_lines(file_pointer) Did python have a build-in function or is there any module that I can download for this? If not, how do I do this to be easiest way. I need to analyze a huge file so I want to read 10000 lines and analyze per time to save memory. Thanks for helping!

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• How can I set breakpoints in an external JS script in Firebug

  - by Manu

  I can easily set breakpoints in embedded JS functions, but I don't see any way of accessing extarnal JS scripts via Firebug unless I happen to enter them during a debug session. Is there a way to do this w/o having to 'explore' my way into the script? @Jason: This is a good point, but in my case I do not have easy access to the script. I am specifically talking about the client scripts which are invoked by the ASP.Net Validators that I would like to debug. I can access them during a debug session through entering the function calls, but I could not find a way to access them directly.

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• Assign grid.arrange to object

  - by Tyler Rinker

  I want to arrange plots with grid.arrange to make more complex coplots and then use grid.arrange to combine these complex coplots. I am using the following solution (http://stackoverflow.com/a/13295880/1000343) in this task to arrange mutliple plots and ensure they have equal widths. Here is a demo of the code: library(ggplot2); library(gridExtra) gA <- ggplotGrob(A) gB <- ggplotGrob(B) maxWidth = grid::unit.pmax(gA$widths[2:5], gB$widths[2:5]) gA$widths[2:5] <- as.list(maxWidth) gB$widths[2:5] <- as.list(maxWidth) x <- grid.arrange(gA, gB, ncol=1) y <- grid.arrange(gA, gB, ncol=1) grid.arrange(x, y, ncol=2) To be clear in my case x and y are slightly different plots with different values. I know grid.arrange isn't returning the plot as other grid based functions.

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• using ajax url to call function

  - by Steven Vanerp

  Hopefully I can ask this correctly cuz I know what I want it to do but can't seem to find any answers from searching. I have a func.php page where I have all my functions and I want ajax to use one function from that page. func.php function toptable() { echo"something happens in here"; } index.php <?php include 'func.php'; ?> <script type="text/javascript"> function check_username() { uname=document.getElementById("username").value; var params = "user_id="+uname; var url = "topoftable()"; $.ajax({ type: 'POST', url: url, dataType: 'html', data: params, beforeSend: function() { document.getElementById("right").innerHTML= 'checking' ; }, complete: function() { }, success: function(html) { document.getElementById("right").innerHTML= html ; } }); } </script> Make sense?

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• Java combine parents of two large inheritance chains

  - by Soylent Green

  I have two parent classes in a huge project, let's say ClassA and ClassB. Each class has many subclasses, which in turn have many subclasses, which in turn have many subclasses, etc. My task is to "marry" these two "families" so that both inherit from a SINGLE parent. I need to essentially make ClassA and ClassB one class (parent) to both of their combined subclasses (children). ClassA and ClassB both currently implement Serializable. I am currently trying to make both inheritance chains inherit from ClassA, and then copy all functions and data members from ClassB into ClassA. This is tedious, and I think a terrible solution. What would be the CORRECT way to solve this problem?

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• How are clientside security vulnerabilities generally discovered?

  - by Jehjoa

  I mean in operating systems or their applications. The only way I can think of is examine binaries for the use of dangerous functions like strcpy(), and then try to exploit those. Though with compiler improvements like Visual Studio's /GS switch this possibility should mostly be a thing of the past. Or am I mistaken? What other ways do people use to find vulnerabilities? Just load your target in a debugger, then send unexpected input and see what happens? This seems like a long and tedious process. Could anyone recommend some good books or websites on this subject? Thanks in advance.

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• strtok program crashing.

  - by baskin

  Hi, the program for strtok given on http://www.opengroup.org/onlinepubs/000095399/functions/strtok.html crashes everytime.. #include <string.h> ... char *token; char *line = "LINE TO BE SEPARATED"; char *search = " "; /* Token will point to "LINE". */ token = strtok(line, search); /* Token will point to "TO". */ token = strtok(NULL, search); If I use a char array for variable 'line', it works. i.e. char line[] = "LINE TO BE SEPARATED" works. Kindly explain.

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• How to give 'Everybody' full rights to a file (programmatically)

  - by egrunin

  I'm modifying an old C++ program to run on Vista. It does not require Admin privileges. I've changed the code to put logfiles in \ProgramData\MyApp\. These logfiles are written with the stdio functions (fopen, fprintf, fclose). Here's the problem: UserA runs the program first, it creates \ProgramData\MyApp\MyLogFile.txt UserB runs the program next, it tries to append to MyLogFile.txt and gets access denied. I tried creating a null SECURITY_DESCRIPTOR and passing that to CreateFile(). That does create a file with "no permissions assigned", but it seems as if the first user to write to the file takes ownership and afterwards all the other non-admin users are out of luck. It's important that all users share the same logfiles, but it's also important that I change as little code as possible.

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• Return from parent sub in Perl

  - by JS Bangs

  I want to write a subroutine which causes the caller to return under certain conditions. This is meant to be used as a shortcut for validating input to a function. What I have so far is: sub needs($$) { my ($condition, $message) = @_; if (not $condition) { print "$message\n"; # would like to return from the *parent* here } return $condition; } sub run_find { my $arg = shift @_; needs $arg, "arg required" or return; needs exists $lang{$arg}, "No such language: $arg" or return; # etc. } The advantage of returning from the caller in needs would then be to avoid having to write the repetitive or return inside run_find and similar functions.

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