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• Creating a Linq->HQL provider

  - by Mike Q

  Hi all, I have a client application that connects to a server. The server uses hibernate for persistence and querying so it has a set of annotated hibernate objects for persistence. The client sends HQL queries to the server and gets responses back. The client has an auto-generated set of objects that match the server hibernate objects for query results and basic persistence. I would like to support using Linq to query as well as Hql as it makes the queries typesafe and quicker to build (no more typos in HQL string queries). I've looked around at the following but I can't see how to get them to fit with what I have. NHibernate's Linq provider - requires using NHibernate ISession and ISessionFactory, which I don't have LinqExtender - requires a lot of annotations on the objects and extending a base type, too invasive What I really want is something that will generate give me a nice easy to process structure to build the HQL queries from. I've read most of a 15 page article written by one of the C# developers on how to create custom providers and it's pretty fraught, mainly because of the complexity of the expression tree. Can anyone suggest an approach for implementing Linq - HQL translation? Perhaps a library that will the cleanup of the expression tree into something more SQL/HQLish. I would like to support select/from/where/group by/order by/joins. Not too worried about subqueries.

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• Best practice accessing an array set within a class

  - by user350599

  I have created a basic class for a customer. I haven't done this before and want to know the best way to access the data. Should I have a get() method for every field in the customer array or should I simply pass the customer array back and access with the page. i.e. Just return the array class Customer { protected $id; protected $customer; public function __construct($customer_id) { $this->id = $customer_id; $this->set_customer(); } protected function set_customer() { $query = mysql_query("SELECT * FROM customer WHERE id = '$this->id'"); $this->customer = mysql_fetch_row($query); } public function get_customer() { return $this->customer; } } versus create a method for each item in the array class Customer { protected $id; protected $customer; public function __construct($customer_id) { $this->id = $customer_id; $this->set_customer(); } protected function set_customer() { $query = mysql_query("SELECT * FROM customer WHERE id = '$this->id'"); $this->customer = mysql_fetch_row($query); } public function get_customer_name() { return $this->customer->customer_name; } ... ... } versus option 3 based on Tobias' feedback: (not sure if syntax is correct) class Customer { protected $id; protected $customer; public function __construct($customer_id) { $this->id = $customer_id; return $this->set_customer(); } protected function set_customer() { $query = mysql_query("SELECT * FROM customer WHERE id = '$this->id'"); return mysql_fetch_row($query); } }

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• CSS Clearing Floats

  - by Frank

  I'm making more of an effort to separate my html structure from presentation, but sometimes when I look at the complexity of the hacks or workarounds to make things work cross-browser, I'm amazed at huge collective waste of productive hours that are put into this. As I understand it, floats were never created for creating layouts, but because many layouts need a footer, that's how they're often being used. To clear the floats, you can add an empty div that clears both sides (div class="clear"). That is simple and works cross browser, but it adds "non-semantic" html rather than solving the presentation problem within the CSS. I realize this, but after looking at all of the solutions with their benefits and drawbacks, it seems to make more sense to go with the empty div (predictable behavior across browsers), rather than create separate stylesheets, including various css hacks and workarounds, etc. which would also need to change as CSS evolves. Is it o.k. to do this as long as you do understand what you're doing and why you're doing it? Or is it better to find the CSS workarounds, hacks and separate structure from presentation at all costs, even when the CSS presentation tools provided are not evolved to the point where they can handle such basic layout issues?

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• Is There a Better Way to Feed Different Parameters into Functions with If-Statements?

  - by FlowofSoul

  I've been teaching myself Python for a little while now, and I've never programmed before. I just wrote a basic backup program that writes out the progress of each individual file while it is copying. I wrote a function that determines buffer size so that smaller files are copied with a smaller buffer, and bigger files are copied with a bigger buffer. The way I have the code set up now doesn't seem very efficient, as there is an if loop that then leads to another if loops, creating four options, and they all just call the same function with different parameters. import os import sys def smartcopy(filestocopy, dest_path, show_progress = False): """Determines what buffer size to use with copy() Setting show_progress to True calls back display_progress()""" #filestocopy is a list of dictionaries for the files needed to be copied #dictionaries are used as the fullpath, st_mtime, and size are needed if len(filestocopy.keys()) == 0: return None #Determines average file size for which buffer to use average_size = 0 for key in filestocopy.keys(): average_size += int(filestocopy[key]['size']) average_size = average_size/len(filestocopy.keys()) #Smaller buffer for smaller files if average_size < 1024*10000: #Buffer sizes determined by informal tests on my laptop if show_progress: for key in filestocopy.keys(): #dest_path+key is the destination path, as the key is the relative path #and the dest_path is the top level folder copy(filestocopy[key]['fullpath'], dest_path+key, callback = lambda pos, total: display_progress(pos, total, key)) else: for key in filestocopy.keys(): copy(filestocopy[key]['fullpath'], dest_path+key, callback = None) #Bigger buffer for bigger files else: if show_progress: for key in filestocopy.keys(): copy(filestocopy[key]['fullpath'], dest_path+key, 1024*2600, callback = lambda pos, total: display_progress(pos, total, key)) else: for key in filestocopy.keys(): copy(filestocopy[key]['fullpath'], dest_path+key, 1024*2600) def display_progress(pos, total, filename): percent = round(float(pos)/float(total)*100,2) if percent <= 100: sys.stdout.write(filename + ' - ' + str(percent)+'% \r') else: percent = 100 sys.stdout.write(filename + ' - Completed \n') Is there a better way to accomplish what I'm doing? Sorry if the code is commented poorly or hard to follow. I didn't want to ask someone to read through all 120 lines of my poorly written code, so I just isolated the two functions. Thanks for any help.

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• How can I have sub-elements of a complex/mixed type with unrestricted order and count?

  - by mbmcavoy

  I am working with XML where some elements will contain text with additional markup. This is similar to this example at W3Schools. However, I need the markup tags to be able to appear in any order and possibly more than once. To modify their example for illustration: <letter> Dear Mr.<name>John Smith</name>. Your order <orderid>1032</orderid> will be shipped on <shipdate>2001-07-13</shipdate>. Thank you, <name>Bob Adams</name> </letter> None of the options presented by W3Schools (on the page following the linked example) allow this XML due to the second <name> element. Their explanation of the "indicators" and my testing are consistent. <xs:sequence> - violates the element order <xs:choice> - more than one kind of element is used. <xs:all> - maxOccurs is restricted to "1". This seems like it should be basic, after all, XHTML allows such things. How do I define my schema to allow this?

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• How to update GUI thread/class from worker thread/class?

  - by user315182

  First question here so hello everyone. The requirement I'm working on is a small test application that communicates with an external device over a serial port. The communication can take a long time, and the device can return all sorts of errors. The device is nicely abstracted in its own class that the GUI thread starts to run in its own thread and has the usual open/close/read data/write data basic functions. The GUI is also pretty simple - choose COM port, open, close, show data read or errors from device, allow modification and write back etc. The question is simply how to update the GUI from the device class? There are several distinct types of data the device deals with so I need a relatively generic bridge between the GUI form/thread class and the working device class/thread. In the GUI to device direction everything works fine with [Begin]Invoke calls for open/close/read/write etc. on various GUI generated events. I've read the thread here (How to update GUI from another thread in C#?) where the assumption is made that the GUI and worker thread are in the same class. Google searches throw up how to create a delegate or how to create the classic background worker but that's not at all what I need, although they may be part of the solution. So, is there a simple but generic structure that can be used? My level of C# is moderate and I've been programming all my working life, given a clue I'll figure it out (and post back)... Thanks in advance for any help.

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• how to create a mootools 1.1 function with array

  - by liz

  i have a series of select lists, that i am using to populate text boxes with ids. so you click a select option and another text box is filled with its id. with just one select/id pair this works fine, but i have multiples, and the only thing that changes is the id of the select and input.. in fact just the ending changes, the inputs all start with featredproductid and the select ids all start with recipesproduct and then both end with the category. i know that listing this over and over for each category is not the way to do it. i think i need to make an array of the categories var cats = ['olive oil', "grains", "pasta"] and then use a forEach function? maybe? here is the clunky code window.addEvent('domready', function() { $('recipesproductoliveoil').addEvent('change', function(e){ pidselected = this.options[this.selectedIndex].getProperty('value') ; $("featuredproductidoliveoil").setProperties({ value: pidselected}); ; }); $('recipesproductgrains').addEvent('change', function(e){ pidselected = this.options[this.selectedIndex].getProperty('value') ; $("featuredproductidgrains").setProperties({ value: pidselected}); ; }); $('recipesproductpasta').addEvent('change', function(e){ pidselected = this.options[this.selectedIndex].getProperty('value') ; $("featuredproductidpasta").setProperties({ value: pidselected}); ; }); $('recipesproductpantry').addEvent('change', function(e){ pidselected = this.options[this.selectedIndex].getProperty('value') ; $("featuredproductidpantry").setProperties({ value: pidselected}); ; }); }); keep in mind this is mootools 1.1 (no i cant update it sorry). i am sure this is kind of basic, something i seem to have wrapping my brain around. but i am quite sure doing it as above is not really good...

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• Java - How to declare table[i][j] elements as instance variables?

  - by JDelage

  All, I am trying to code a Connect4 game. For this, I have created a P4Game class and a P4Board class which represents the i X j dimensions of the Connect4 board. In P4Game, I have the following: public class P4Game{ //INSTANCE VARIABLES private int nbLines; private int nbColumns; private P4Board [][] position; //CONSTRUCTOR public P4Game(int nbLines, int nbColumns){ this.nbColumns = nbColumns; this.nbLines = nbLines; P4Board [][] position = new P4Board [nbLines][nbColumns]; //Creates the table to receive the instances of the P4Board object.*/ for (int i=0; i<nbLines; i++){ for (int j=0; j<nbColumns; j++){ this.position[i][j] = new P4Board(i,j); //Meant to create each object at (line=i, column=j) } } } This causes a NullPointerException in the nested loops where I mention this.position[i][j]. I reference those objects in other methods of this class so I need them to be instance variables. I suppose the exception is due to the fact that I have not listed the table element position[i][j] as an instance variable at the beginning of the class. my question to people here is (1) is my assumption correct, and if so (2) what would be the syntax to declare instance variables of this form? Thank you all for your help with what I realize is a very basic question. Hopefully it will also benefit other newbies. Cheers, JDelage

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• SQL Server getdate() to a string like "2009-12-20"

  - by Adam Kane

  In Microsoft SQL Server 2005 and .NET 2.0, I want to convert the current date to a string of this format: "YYYY-MM-DD". For example, December 12th 2009 would become "2009-12-20". How do I do this in SQL. The context of this SQL statement in the table definiton. In other words, this is the default value. So when a new record is created the default value of the current date is stored as a string in the above format. I'm trying: SELECT CONVERT(VARCHAR(10), GETDATE(), 102) AS [YYYY.MM.DD] But SQL server keeps converting that to: ('SELECT CONVERT(VARCHAR(10), GETDATE(), 102) AS [YYYY.MM.DD]') so the result is just: 'SELECT CONVERT(VARCHAR(10), GETDATE(), 102) AS [YYYY.MM.DD]' Here's a screen shot of what the Visual Studio server explorer, table, table definition, properties shows: These wrapper bits are being adding automatically and converting it all to literal string: (N' ') Here's the reason I'm trying to use something other than the basic DATETIME I was using previously: This is the error I get when hooking everything to an ASP.NET GridView and try to do an update via the grid view: Server Error in '/' Application. The version of SQL Server in use does not support datatype 'date'. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.ArgumentException: The version of SQL Server in use does not support datatype 'date'. Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [ArgumentException: The version of SQL Server in use does not support datatype 'date'.] Note: I've added a related question to try to get around the SQL Server in use does not support datatype 'date' error so that I can use a DATETIME as recommended.

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• how to put header authentication into a form using php?

  - by SkyWookie

  Hey guys, for the page I am doing needs a login authentication using Twitter (using tweetphp API). For test purposes I used this code below to do a successful login: if (!isset($_SERVER['PHP_AUTH_USER'])){ header('WWW-Authenticate: Basic realm="Enter your Twitter username and password:"'); header('HTTP/1.0 401 Unauthorized'); echo 'Please enter your Twitter username and password to view your followers.'; exit(); } $username = $_SERVER['PHP_AUTH_USER']; $password = $_SERVER['PHP_AUTH_PW']; The problem now is, I want to integrate it into a form, so far I have the following: <form action="logincheck.php" method="post" class="niceform" > <fieldset> <legend>Twitter Login:</legend> <dl> <dt><label for="email">Twitter Username:</label></dt> <dd><input type="text" name="username" id="username" size="32" maxlength="128" /></dd> </dl> <dl> <dt><label for="password">Password:</label></dt> <dd><input type="password" name="password" id="password" size="32" maxlength="32" /></dd> </dl> </fieldset> <fieldset class="action"> <input type="submit" name="submit" id="submit" value="Submit" /> I am sending it to logincheck.php, this is where I think I get stuck. I am not sure how to compare the form data with Twitter's login data. I was trying a similar if statement as I used in the first code (box that pops up before page loads), but I couldn't wrap my head around it. Thanks again guys!

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• Socket isn't listed by netstat unless using certain ports

  - by illuzive

  I'm a computer science student with a few years of programming experience. Yesterday, while working on a project (Mac OS X, BSD sockets) at school, I encountered a strange problem. I was adding several modules to a very basic "server" (mostly a bunch of functions to set up and manage an UDP socket on a certain port). While doing this, I started the server from time to time in order to see that everything worked like it should. I've been using port 32000 during the development of the server. When I start the server and run netstat, the socket is listed as expected. > netstat -p UDP | grep 32000 udp46 0 0 *.32000 *.* However, when I run the server on other ports (random (10000 - 50000)), it's not listed by netstat. My thought was that I had somehow hard coded the port somewhere in the code, but that's not the case. The thing is - I can connect to the socket on any of the tested ports, and it reads data sent to it without any problem at all. It just doesn't get listed by netstat. What I wonder, is if anyone of you have any idea of why this happens? Note: Although this is a project at school, it's not homework. This is just something I want to understand for my own benefit.

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• Warning: cast increases required alignment

  - by dash-tom-bang

  I'm recently working on this platform for which a legacy codebase issues a large number of "cast increases required alignment to N" warnings, where N is the size of the target of the cast. struct Message { int32_t id; int32_t type; int8_t data[16]; }; int32_t GetMessageInt(const Message& m) { return *reinterpret_cast<int32_t*>(&data[0]); } Hopefully it's obvious that a "real" implementation would be a bit more complex, but the basic point is that I've got data coming from somewhere, I know that it's aligned (because I need the id and type to be aligned), and yet I get the message that the cast is increasing the alignment, in the example case, to 4. Now I know that I can suppress the warning with an argument to the compiler, and I know that I can cast the bit inside the parentheses to void* first, but I don't really want to go through every bit of code that needs this sort of manipulation (there's a lot because we load a lot of data off of disk, and that data comes in as char buffers so that we can easily pointer-advance), but can anyone give me any other thoughts on this problem? I mean, to me it seems like such an important and common option that you wouldn't want to warn, and if there is actually the possibility of doing it wrong then suppressing the warning isn't going to help. Finally, can't the compiler know as I do how the object in question is actually aligned in the structure, so it should be able to not worry about the alignment on that particular object unless it got bumped a byte or two?

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• Run Javascript on the body of a Gmail message

  - by saturn

  I want to display LaTeX math in the gmail messages that I receive, so that for example $\mathbb P^2$ would show as a nice formula. Now, there are several Javascripts available (for example, this one, or MathJax which would do the job, I just need to call them at the right time to manipulate the gmail message. I know that this is possible to do in "basic HTML" and "print" views. Is it possible to do in the standard Gmail view? I tried to insert a call to the javascript right before the "canvas_frame" iframe, but that did not work. My suspicion is that manipulating a Gmail message by any Javascript would be a major security flaw (think of all the malicious links one could insert) and that Google does everything to prevent this. And so the answer to my question is probably 'no'. Am I right in this? Of course, it would be very easy for Google to implement viewing of LaTeX and MathML math simply by using MathJax on their servers. I made the corresponding Gmail Lab request, but no answer, and no interest from Google apparently. So, again: is this possible to do without Google's cooperation, on the client side?

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• A feeling that I'm not that good developer

  - by Karim

  Hi, Im having a strange feeling, but let me first introduce myself as a software developer. I started to program when I was still a kid, I had about 10 or 11 years. I really enjoy my work and never get bored from it. It's amazing how somebody could be paid for what he really likes to do and would be doing it anyway even for free. WHen I first started to program, I was feeling proud of what I was doing, each application I built was for me a success and after 2-3 year I had a feeling that I'm a coding guru. It was a nice feeling ;-) But the more I was in the field, the more types of software I started to develop I was starting to have a feeling that I'm completely wrong in that I'm guru. I felt that I'm not even a mediocre developer. Each new field I start to work on is giving me this feeling. Like when I once developed a device driver for a client, I saw how much I need to learn about device drivers. When I developed a video filter for an application, I saw how much do I still need to learn about DirectShow, Color Spaces, and all the theory behind that. The worst thing was when I started to learn algorithms. It was several years ago. I knew then the basic structures and algorithms like the sorting, some types of trees, some hashtables, strings etc.. and when I really wanted to learn a group of structures I learned about 5-6 new types and saw that in fact even this small group has several hundred subtypes of structures. It's depressing how little time people have in their lives to learn all this stuff. I'm now a software developer with about 10 years of experience and I still feel that I'm not a proficient developer when I think about things that others do in the industry. Is this normal what I'm experiencing or is it a sign of a destructive excessive ambition? Thanks in advance for any comments.

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• What would cause objectForKey: to return null with a valid string in place?

  - by theMikeSwan

  I am having an issue with NSDictionary returning null for an NSString even though the string in in the dictionary. Here is the code: - (void)sourceDidChange:(NSNotification *)aNote { NSDictionary *aDict = [aNote userInfo]; DLog(@"%@", aDict); NSString *newSourceString = [aDict objectForKey:@"newSource"]; DLog(@"%@", newSourceString); newSourceString = [newSourceString stringByReplacingOccurrencesOfString:@" " withString:@""]; DLog(@"%@", newSourceString); NSString *inspectorString = [newSourceString stringByAppendingString:@"InspectorController"]; DLog(@"%@", inspectorString); newSourceString = [newSourceString stringByAppendingString:@"ViewController"]; DLog(@"%@", newSourceString); } And I get the following log statements: 2010-04-17 23:50:13.913 CoreDataUISandbox[13417:a0f] -[RightViewController sourceDidChange:] newSource = "Second View"; 2010-04-17 23:50:13.914 CoreDataUISandbox[13417:a0f] -[RightViewController sourceDidChange:] (null) 2010-04-17 23:50:13.916 CoreDataUISandbox[13417:a0f] -[RightViewController sourceDidChange:] (null) 2010-04-17 23:50:13.917 CoreDataUISandbox[13417:a0f] -[RightViewController sourceDidChange:] (null) 2010-04-17 23:50:13.917 CoreDataUISandbox[13417:a0f] -[RightViewController sourceDidChange:] (null) As you can see the string is in the dictionary under the key newSource, yet when I call objectForKey: I get null. I have even tried the fallback option of cleaning the project. Has anyone ever run into this, or have I just forgotten something really basic?

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• IBM WESB/WAS JCA security configuration

  - by user594883

  I'm working with IBM tools. I have a Websphere ESB (WESB) and a CICS transaction gateway (CTG). The basic set-up is as follows: A SOAP service needs data from CICS. The SOAP-service is connecting to service bus (WESB) to handle data and protocol transformation and then WESB calls the CTG which in turn calls CICS and the reply is handled vice verse (synchronously). WESB calls the CTG using Resource Adapter and JCA connector (or CICS adapter as it is called in WESB). Now, I have all the pieces in place and working. My question is about the security, and even though I'm working with WESB, the answer is probably the same as in Websphere Application Server (WAS). The Resource Adaper is secured using JAAS - J2C authentication data. I have configured the security using J2C authentication data entry, so basically I have a reference in the application I'm running and at runtime the application does a lookup for the security attributes from the server. So basically I'm always accessing the CICS adapter with the same security reference. My problem is that I need to access the resource in more dynamic way in the future. The security cannot be welded into the application anymore but instead given as a parameter. Could some WESB or WAS guru help me out, how this could be done in WESB/WAS exactly?

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• Link error for user defined class type template parameter

  - by isurulucky

  Hi, I implemented a Simple STL map in C++. Factored out the comparison as a type as I was instructed to, then implemented the comparison as shown below: template <typename T> int KeyCompare<T>::operator () (T tKey1, T tKey2) { if(tKey1 < tKey2) return -1; else if(tKey1 > tKey2) return 1; else return 0; } here, tKey1 and tKet2 are the two keys I'm comparing. This worked well for all the basic data types and string. I added a template specialization to compare keys of a user defined type named Test and added a specialization as follows: int KeyCompare<Test>::operator () (Test tKey1, Test tKey2) { if(tKey1.a < tKey2.a) return -1; else if(tKey1.a > tKey2.a) return 1; else return 0; } when I run this, I get a linking error saying SimpleMap.obj : error LNK2005: "public: int __thiscall KeyCompare::operator()(class Test,class Test)" (??R?$KeyCompare@VTest@@@@QAEHVTest@@0@Z) already defined in MapTest.obj SimpleMap.obj : error LNK2005: "public: __thiscall KeyCompare::~KeyCompare(void)" (??1?$KeyCompare@VTest@@@@QAE@XZ) already defined in MapTest.obj SimpleMap.obj : error LNK2005: "public: __thiscall KeyCompare::KeyCompare(void)" (??0?$KeyCompare@VTester@@@@QAE@XZ) already defined in MapTest.obj MapTest.cpp is the test harness class in which I wrote the test case. I have used include guards as well, to stop multiple inclusions. Any idea what the matter is?? Thank you very much!!

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• my dialog box did not show up whene i compile it using sdk 7.1,

  - by zirek

  hello and welcom everyone .. i'd like to build a win32 application using sdk 7.1, i create the dialog box using visual c++ 2012 resource editor, i copy resource.rc and resource.h to my folder and i write this simple main.cpp file: #include <windowsx.h> #include <Windows.h> #include <tchar.h> #include "resource.h" #define my_PROCESS_MESSAGE(hWnd, message, fn) \ case(message): \ return( \ SetDlgMsgResult(hWnd, uMsg, \ HANDLE_##message((hWnd), (wParam), (lParam), (fn)) )) \ LRESULT CALLBACK DlgProc(HWND, UINT, WPARAM, LPARAM); BOOL Cls_OnInitDialog(HWND hwnd, HWND hwndFocus, LPARAM lParam); void Cls_OnCommand(HWND hwnd, int id, HWND hwndCtl, UINT codeNotify); int WINAPI _tWinMain( HINSTANCE hInstance, HINSTANCE, LPTSTR, int iCmdLine ) { DialogBoxParam( hInstance, MAKEINTRESOURCE(IDD_INJECTOR), NULL, (DLGPROC) DlgProc, NULL ); return FALSE; } LRESULT CALLBACK DlgProc( HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam ) { switch (uMsg) { my_PROCESS_MESSAGE(hwnd, WM_INITDIALOG, Cls_OnInitDialog); my_PROCESS_MESSAGE(hwnd, WM_COMMAND, Cls_OnCommand); default: break; } return DefWindowProc(hwnd, uMsg, wParam, lParam); } BOOL Cls_OnInitDialog(HWND hwnd, HWND hwndFocus, LPARAM lParam) { return TRUE; } void Cls_OnCommand(HWND hwnd, int id, HWND hwndCtl, UINT codeNotify) { switch(id) { case IDCANCEL: EndDialog(hwnd, id); break; default: break; } } then i use the following command line to compile my code, wich i found on this forum cl main.cpp /link /SUBSYSTEM:WINDOWS user32.lib my problem is that my dialog box did not show up, and when i use procexp, to see what happen, i found that that my application is created then closed in the same time, and what make me wondering is that its working fine on visual c++ 2012. my sdk 7.1, installed correctly, i testing it against a basic window without any resource file any ideas, ill be really thankful Best, Zirek

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• How to speed-up python nested loop?

  - by erich

  I'm performing a nested loop in python that is included below. This serves as a basic way of searching through existing financial time series and looking for periods in the time series that match certain characteristics. In this case there are two separate, equally sized, arrays representing the 'close' (i.e. the price of an asset) and the 'volume' (i.e. the amount of the asset that was exchanged over the period). For each period in time I would like to look forward at all future intervals with lengths between 1 and INTERVAL_LENGTH and see if any of those intervals have characteristics that match my search (in this case the ratio of the close values is greater than 1.0001 and less than 1.5 and the summed volume is greater than 100). My understanding is that one of the major reasons for the speedup when using NumPy is that the interpreter doesn't need to type-check the operands each time it evaluates something so long as you're operating on the array as a whole (e.g. numpy_array * 2), but obviously the code below is not taking advantage of that. Is there a way to replace the internal loop with some kind of window function which could result in a speedup, or any other way using numpy/scipy to speed this up substantially in native python? Alternatively, is there a better way to do this in general (e.g. will it be much faster to write this loop in C++ and use weave)? ARRAY_LENGTH = 500000 INTERVAL_LENGTH = 15 close = np.array( xrange(ARRAY_LENGTH) ) volume = np.array( xrange(ARRAY_LENGTH) ) close, volume = close.astype('float64'), volume.astype('float64') results = [] for i in xrange(len(close) - INTERVAL_LENGTH): for j in xrange(i+1, i+INTERVAL_LENGTH): ret = close[j] / close[i] vol = sum( volume[i+1:j+1] ) if ret > 1.0001 and ret < 1.5 and vol > 100: results.append( [i, j, ret, vol] ) print results

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• Effective books for learning the intricacies of business application development?

  - by OffApps Cory

  I am a self taught "developer". I use the term loosely because I only know enough to make myself dangerous. I have no theory background, and I only pick up things to get this little tool to work or make that control do what I want. That said, I am looking for some reading material that explains some of the theory behind application development especially from a business standpoint. Really I need to understand what all of these terms that float around really talk about. Business Logic Layer, UI abstraction level and all that. Anyone got a reading list that they feel helped them understand this stuff? I know how to code stuff up so that it works. It is not pretty mostly because I don't know the elegant way of doing it, and it is not planned out very well (I also don't know how to plan an application). Any help would be appreciated. I have read a number of books on what I thought was the subject, but they all seem to rehash basic coding and what-not. This doesn't have to be specific to VB.NET or WPF (or Entity Framework) but anything with those items would be quite helpful.

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• Can I use foreign key restrictions to return meaningful UI errors with PHP

  - by Shane

  I want to start by saying that I am a big fan of using foreign keys and have a tendency to use them even on small projects to keep my database from being filled with orphaned data. On larger projects I end up with gobs of keys which end up covering upwards of 8 - 10 layers of data. I want to know if anyone could suggest a graceful way of handling 'expected errors' from the MySQL database in a way that I can construct meaningful messages for the end user. I will explain 'expected errors' with an example. Lets say I have a set of tables used for basic discussions: discussion questions responses users Hierarchically they would probably look something like this: -users --discussion ---questions ----responses When I attempt to delete a user the FKs will check discussions and if any discussion exist the deletion is restricted, deleting discussion checks questions, deleting questions checks responses. An 'expected error' in this case would be attempting to delete a user--unless they are newly created I can anticipate that one or more foreign keys will fail causing an error. What I WANT to do is to catch that error on deletion and be able to tell the end user something like 'We're sorry, but all discussions must be removed before you can delete this user...'. Now I know I can keep and maintain matching arrays in PHP and map specific errors to messages but that is messy and prone to becoming stagnant, or I could manually run a set of selects prior to attempting the deletion, but then I am doing just as much work as without using FKs. Any help here would be greatly appreciated, or if I am just looking at this completely wrong then please let me know. On a side note I generally use CodeIgniter for my application development, so if that would open up an avenue through that framework please consider that in your answers. Thanks in Advance

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• Why not put all braces inline in C++/C#/Java/javascript etc.?

  - by DanM

  Of all the conventions out there for positioning braces in C++, C#, Java, etc., I don't think I've ever seen anyone try to propose something like this: public void SomeMethod(int someInput, string someOtherInput) { if (someInput > 5) { var addedNumber = someInput + 5; var subtractedNumber = someInput - 5; } else { var addedNumber = someInput + 10; var subtractedNumber = someInput; } } public void SomeOtherMethod(int someInput, string someOtherInput( { ... } But why not? I'm sure it would take some getting used to, but I personally don't have any difficulty following what's going on here. I believe indentation is the dominant factor in being able to see how code is organized into blocks and sub-blocks. Braces are just visual noise to me. They are these ugly things that take up lines where I don't want them. Maybe I just feel that way because I was weened on basic (and later VB), but I just don't like braces taking up lines. If I want a gap between blocks, I can always add an empty line, but I don't like being forced to have gaps simply because the convention says the closing brace needs to be on its own line. I made this a community wiki because I realize this is not a question with a defined answer. I'm just curious what people think. I know that no one does this currently (at least, not that I've seen), and I know that the auto-formatter in my IDE doesn't support it, but are there are any other solid reasons not to format code this way, assuming you are working with a modern IDE that color codes and auto-indents? Are there scenarios where it will become a readability nightmare? Better yet, are you aware of any research on this?

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• Finding missing files by checksum

  - by grw

  Hi there, I'm doing a large data migration between two file systems (let's call them F1 and F2) on a Linux system which will necessarily involve copying the data verbatim into a differently-structured hierarchy on F2 and changing the file names. I'd like to write a script to generate a list of files which are in F1 but not in F2, i.e. the ones which weren't copied by the migration script into the new hierarchy, so that I can go back and migrate them manually. Unfortunately for reasons not worth going into, the migration script can't be modified to list files that it doesn't migrate. My question differs from this previously answered one because of the fact that I cannot rely on filenames as a comparison. I know the basic outline of the process would be: Generate a list of checksums for all files, recursing through F1 Do the same for F2 Compare the lists and generate a negative intersection of the checksums, ignoring the file names, to find files which are in F1 but not in F2. I'm kind of stuck getting past that stage, so I'd appreciate any pointers on which tools to use. I think I need to use the 'comm' command to compare the list of file checksums, but since md5sum, sha512sum and the like put the file name next to the checksum, I can't see a way to get it to bring me a useful comparison. Maybe awk is the way to go? I'm using Red Hat Enterprise Linux 5.x. Thanks.

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• iPhone + Provisioning Profile + app-info.plist + entitlements.plist = iPhoneApp ? How ? What exactly

  - by sagar

  To execute my application in iPhone first of all I have to add provisioning profile in to my iPhone. Good. But I don't understand the reason behind adding a entitlements.plist in iphone application in xCode under resources. What does that entitlements.plist file do actually ? Why that .plist file have only single Boolean in it ? (get-task-allow) Can't we add that Boolean variable to application-info.plist ? I mean, I can't find the reason behind storing a single Boolean variable in separate plist file. Instead application-info.plist already contains many many application settings. Can't we just add this Boolean variable to application-info.plist. Ok, any way. I know - it won't be possible. Because we have to follow - what apple says. But, here main intention behind all these was "what is the basic need of entitlements.plist ?" or "what is the functionality of entitlements.plist ?" "How provisioning profile, entitlements.plist, application-info.plist & iPhone application compile all together & make verification on iPhone & execute it on iPhone ? "

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• directory resource does not create directory

  - by Dan Tenenbaum

  I have a Vagrantfile that provisions a VM by running a chef recipe. The first resource in the chef recipe is: directory "/downloads" do owner "root" group "root" mode "0755" action :create end # check that it worked: raise "/downloads doesn't exist!" unless File.exists? "/downloads" When I run this at work, it works fine. When I run it at home, it fails, the exception is raised when I check to see if /downloads exists. I'm not sure why this is happening. I would expect it to behave identically, since the underlying Vagrant box is the same both at work and at home. I am a chef newb so perhaps there is something I am not understanding about the order in which the resources are run within my recipe? I would expect them to run in sequential order... I also tried putting a notifies call inside the directory block, where I call another execute block :immediately. That works, but inside the second execute block I test to see whether /downloads has been created and it hasn't. Clearly I'm missing something very basic.

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