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• Dealing with Expression Blend's lack of support for C++/CLI projects

  - by Brian Ensink

  I have a WPF C# project that references a C++/CLI mixed mode project. I'm having trouble using the WPF project in Expression Blend 3. I'm new to Blend so perhaps this is obvious, but it won't display the xaml designer properly until it builds the project. In my case it complains that my custom commands are not "recognized or accessible" and the solution is to build the project in Blend. But I can't build the project because it references a C++/CLI mixed mode project which Blend won't load. The WPF project is pure C# it just happens to reference a C++/CLI mixed mode project but I'm not asking Blend to do anything with the mixed-mode assembly. How can I work around this problem? Edit: I was able to get it to build by removing the reference to the C++/CLI mixed mode project and replacing it with a reference to the actual assembly. However this is not ideal because in my past experience Visual Studio will not always be able to resolve the reference when switching between release and debug configurations.

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• How to implement a log window in a web browser?

  - by Jeremy Friesner

  Hi all, I'm interested in adding an HTML/web-browser based "log window" to my net-enabled device. Specifically, my device has a customized web server and an event log, and I'd like to be able to leave a web browser window open to e.g. http://my.devices.ip.address/system_log and have events show up as text in the web browser window as they happen. People could then use this as a quick way to monitor what the system is doing, without needing run any special software. My question is, what is the best way to implement this? I've tried the obvious approach -- just have my device's embedded web server hold the HTTP/TCP connection open indefinitely, and write the necessary text to the TCP socket when an event occurs -- but the problem with that is that most web browsers (e.g. Safari) don't display the web page until the server has closed the TCP connection has been closed, and so the result is that the log data never appears in the web browser, it just acts as if the page is taking forever to load. Is there some trick to make this work? I could implement it as a Java applet, but I'd much prefer something more lightweight/simple, either using only HTML or possibly HTML+JavaScript. Also I'd like to avoid having the web browser 'poll' the server, since that would either introduce too much latency (if the reload delay was large) or put load on the system (if the delay was small)

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• How can I use a meter-style progress bar?

  - by Yadyn

  In Vista/7, the Windows Explorer shell window makes use of a special kind of static progress bar to display hard drive space. With default styles, this bar is blue colored and non-animated. It also turns red colored when it gets close to being full (low disk space). Using messaging, I can tell the Windows Forms ProgressBar control to update its state to Paused and Error (yellow and red colored, respectively), which works fine, but these are still specific to progress. In the Windows User Experience Guidelines, it specifically points out this "meter" variant of the Progress Bar: This pattern isn't a progress bar, but it is implemented using the progress bar control. Meters have a distinct look to differentiate them from true progress bars. They say it "is implemented using the progress bar control", so... how? What message could I send to the control to have it behave this way? I've seen that you can send messages for setting the bar color, but the documentation says these calls are ignored when visual styles are enabled. Nothing else in the Windows API documentation for raw ProgressBar controls seemed to suggest a way to do this. Am I just stuck making a custom drawn bar? I'd really like to utilize the OS whenever possible so that the application will appear consistent throughout different OS versions. I realize that pre-Vista versions probably won't support this, though. I'm looking for a Windows Forms solution, but I wonder if it is even exposed at all via Win32 API.

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• IIS 6.0 Rewrite rules for Wordpress (Forward slash not working and other things)

  - by DigitalBlade

  Hi, I am using Wordpress 3.0.4 on IIS 6.0 and Windows Server 2003, hosted by a company. I was having lots of issues using permalinks. I have fixed most, but now I have an issue with a forward-slash not being added to the address. This would be fine on most websites, but not on IIS for some reason. Specifically, if I go to "mysite.com/wp-admin" I can log-in and get to the dashboard, but as soon as I click anything there i am redirected to a broken link. For example: "mysite.com/post-new.php". If I add the slash at the end it's fine. So I tried to have a rewrite rule to automatically add the slash to such address: RewriteRule /wp-admin /wp-admin/ [L] But it still doesn't work. For your reference, here's the complete file: [ISAPI_Rewrite] RewriteBase / RewriteCond ${REQUEST_FILENAME} !-f RewriteCond ${REQUEST_FILENAME} !-d # For special WordPress folders (e.g. theme, admin, etc.) RewriteRule /wp-admin /wp-admin/ [L] RewriteRule /wp-(.*) /wp-$1 [L] RewriteRule /(.*\.(?:jpg|jpeg|gif|css|txt|xml|html|png|js)) /$1 [I,L] # Rules to ensure that normal content gets through RewriteRule /images/(.*) /images/$1 [L] RewriteRule /favicon.ico /favicon.ico [L] RewriteRule /robots.txt /robots.txt [L] RewriteRule /phpmyadmin/(.*) /phpmyadmin/$1 [L] RewriteRule /phpmyadmin /phpmyadmin/ [L] # For all WordPress pages RewriteRule ^/$ /index.php [L] RewriteRule /(.*) /index.php/$1 [L] Any ideas? Thanks in advance

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• PHP resizing PNGs results in corrupted files

  - by Robert

  I have a PHP script that resizes .jpg, .gif, and .png files to a bounding box. $max_width = 500; $max_height = 600; $filetype = $_FILES["file"]["type"]; $source_pic = "img/" . $idnum; if($filetype == "image/jpeg") { $src = imagecreatefromjpeg($source_pic); } else if($filetype == "image/png") { $src = imagecreatefrompng($source_pic); } else if($filetype == "image/gif") { $src = imagecreatefromgif($source_pic); } list($width,$height)=getimagesize($source_pic); $x_ratio = $max_width / $width; $y_ratio = $max_height / $height; if( ($width <= $max_width) && ($height <= $max_height) ) { $tn_width = $width; $tn_height = $height; } else if (($x_ratio * $height) < $max_height) { $tn_height = ceil($x_ratio * $height); $tn_width = $max_width; } else { $tn_width = ceil($y_ratio * $width); $tn_height = $max_height; } $tmp = imagecreatetruecolor($tn_width,$tn_height); imagecopyresampled($tmp,$src,0,0,0,0,$tn_width, $tn_height,$width,$height); $destination_pic = "img/thumbs/" . $idnum . "thumb"; if($filetype == "image/jpeg") { imagejpeg($tmp,$destination_pic,80); } else if($filetype == "image/png") { imagepng($tmp,$destination_pic,80); } else if($filetype == "image/gif") { imagegif($tmp,$destination_pic,80); } imagedestroy($src); imagedestroy($tmp); The script works fine with jpeg and gif but when running on a png the file will be corrupted. Is there anything special I need to use when working with a png? I have never worked with this sort of thing in PHP so I'm not very familiar with it.

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• Bad idea to have the same object, have a different side effect after method call.

  - by Nathan W

  Hi all, I'm having a bit of a gesign issue(again). Say I have this Buttonpad object: now this object is a wrapper object over one in a com object. At the moment it has a method on it called CreateInto(IComObject). Now to make a new button pad in the Com Object. You do: ButtonPad pad = new ButtonPad(); pad.Title = "Hello"; // Set some more properties. pad.CreateInto(Cominstance); The createinfo method will excute the right commands to buid the button pad in the com object. After it has been created it any calls against it are foward to the underlying object for change so: pad.Title = "New title"; will call the com object to set the title and also set the internal title variable. Basically any calls before the CreateInfo method only affect the .NET object anything after has the side effect of calling the com object also. I'm not very good at sequence diagrams but here is my attempt to explain whats going on: This doesn't feel good to me, it feels like I'm lying to the user about what the button pad does. I was going to have a object called WrappedButtonPad, which is returned from CreateInto and the user could make calls against that to make changes to the Com Object, but I feel having two objects that almost do the same thing but only differ by names might be even worse. Are these valid designs, or am I right to be worried? How else would you handle a object the can create and query a com object?

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• Are C++ exceptions sufficient to implement thread-local storage?

  - by Potatoswatter

  I was commenting on an answer that thread-local storage is nice and recalled another informative discussion about exceptions where I supposed The only special thing about the execution environment within the throw block is that the exception object is referenced by rethrow. Putting two and two together, wouldn't executing an entire thread inside a function-catch-block of its main function imbue it with thread-local storage? It seems to work fine: #include <iostream> #include <pthread.h> using namespace std; struct thlocal { string name; thlocal( string const &n ) : name(n) {} }; thlocal &get_thread() { try { throw; } catch( thlocal &local ) { return local; } } void print_thread() { cerr << get_thread().name << endl; } void *kid( void *local_v ) try { thlocal &local = * static_cast< thlocal * >( local_v ); throw local; } catch( thlocal & ) { print_thread(); return NULL; } int main() try { thlocal local( "main" ); throw local; } catch( thlocal & ) { print_thread(); pthread_t th; thlocal kid_local( "kid" ); pthread_create( &th, NULL, &kid, &kid_local ); pthread_join( th, NULL ); print_thread(); return 0; } Is this novel or well-characterized? Was my initial premise correct? What kind of overhead does get_thread incur in, say, GCC and VC++? It would require throwing only exceptions derived from struct thlocal, but altogether this doesn't feel like an unproductive insomnia-ridden Sunday morning…

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• Outstanding issues with jQuery.ajax() in IE8?

  - by RyanV

  I am loading feed-items into a ul using this jQuery .ajax() call, which I basically lifted from http://www.makemineatriple.com/2007/10/bbcnewsticker/ var timestamp = true; //set whether timestamp is displayed in $.ajax({ type: "GET", url: "sample-feed.xml", dataType: "xml", success: function(xml) { $(xml).find('item').each(function(){ var title = $(this).find('title').text(); var link = $(this).find('link').text(); if(title.length >=57){ title = title.substring(0,54) + "..."; } var addItem = '<li class="tickerTitle"><a href="'+link+'">'+title+'</a>'; if (Boolean(timestamp)== true){ var time = new Date(Date.parse($(this).find('pubDate').text())); addItem +='<span class="timestamp">' + makestamp(time) +'</span></li>'; } $('ul#news').append(addItem); }); It works in Chrome 4 and Firefox 3.6, but I load it up in IE8 and somehow the ajax call fails. I have tried to use IE8's Developer tools to see where exactly it fails, but I haven't been successful yet. So two questions Is there anything blatantly wrong with my ajax call here that could be preventing me from seeing it in IE where it works in FF/Chrome? Are there any special considerations I have to make for the Internet Explorer family of browsers with regards to this particular jQuery method? I've done some googling on this but nothing obvious is coming up. One other note: I am currently using jQuery 1.3.2 due to some legacy scripts on the same site. I did try loading 1.4.2 and it had the same results on IE8

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• Scanning, Checking, Converting, Copying values ... How to ? -- C --

  - by ZaZu

  Hi there, Its been a while now and im still trying to get a certain code to work. I asked some question about different commands etc. before, but now I hope this is the final one (combining all questions in one code). I basically want to : *Scan an input (should be character ? ) *Check if its a number *If not, return error *Convert that character into a float number *Copy the value to another variable ( I called it imp here) Here is what I came up with : #include<stdio.h> #include<stdlib.h> #include<ctype.h> main(){ int digits; float imp=0; int alpha; do{ printf("Enter input\n\n"); scanf("\n%c",&alpha); digits=isdigit(alpha); if(digits==0){ printf("error\n\n"); } imp=atof(alpha); }while(digits==0); } The problem is this code does not work at all ... It gives me that atof must be of a const char and whenever I try changing it around, it just keeps failing. I am frustrated and forced to ask here, because I believe I have tried alot and I keep failing, but I wont be relieved until I get it to work xD So I really need your help guys. Please tell me why isnt this code working, what am I doing wrong ? I am still learning C and really appreciate your help :)

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• WPF Event Handler in Another Class

  - by Nathan Tornquist

  I have built a series of event handlers for some custom WPF controls. The event handles format the text displayed when the user enters or leaves a textbox based on the type of data contained (Phone number, zip code, monetary value, etc.) Right now I have all of the events locally in the C# code directly attached to the xaml. Because I have developed a could controls, this means that the logic is repeated a lot, and if I want to change the program-wide functionality I would have to make changes everywhere the event code is located. I am sure there is a way to put all of my event handlers in a single class. Can anyone help point me in the correct direction? I saw this article: Event Handler located in different class than MainWindow But I'm not sure if it directly relates to what I'm doing. I would rather make small changes to the existing logic that I have, as it works, then rewrite everything into commands. I would essentially like to something like this if possible: LostFocus="ExpandedTextBoxEvents.TextBox_LostFocus" It is easy enough to do something like this: private void TextBoxCurrencyGotFocus(object sender, RoutedEventArgs e) { ExpandedTextBoxEvents.TextBoxCurrencyGotFocus(sender, e); } private void TextBoxCurrencyLostFocus(object sender, RoutedEventArgs e) { ExpandedTextBoxEvents.TextBoxCurrencyLostFocus(sender, e); } But that is less elegant.

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• jQuery: How to use modifier keys on form submit?

  - by Svish

  Say I have a form that looks like this: [ Animal name input field ] Add button If I type a name and hit enter, an animal with the given name is added to a table. Works fine. What I would like now is to call the current way of working "quick add" and add a new feature called "slow add", which I am not quite sure how to do. Basically what I want is that if for example the shift key is held down when enter or the button is clicked, I want the form submit method to do something slightly different. In my case I want it to open up a form where more details on the animal can be added before it is added to the table. Problem is I'm not quite sure how to do this. I have tried add a FireBug console.info(eventData) in my current submit function and I have found that the eventData contains an altKey, shiftKey and controlKey property, but they are always undefined even when I hold those keys down. So, does anyone know how I can do something special in my submit handler when certain modifier keys were pressed when the form was submitted?

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• Link compatibility between C++ and D

  - by Caspin

  D easily interfaces with C. D just as easily interfaces with C++, but (and it's a big but) the C++ needs to be extremely trivial. The code cannot use: namespaces templates multiple inheritance mix virtual with non-virtual methods more? I completely understand the inheritance restriction. The rest however, feel like artificial limitations. Now I don't want to be able to use std::vector<T> directly, but I would really like to be able to link with std::vector<int> as an externed template. The C++ interfacing page has this particularly depressing comment. D templates have little in common with C++ templates, and it is very unlikely that any sort of reasonable method could be found to express C++ templates in a link-compatible way with D. This means that the C++ STL, and C++ Boost, likely will never be accessible from D. Admittedly I'll probably never need std::vector while coding in D, but I'd love to use QT or boost. So what's the deal. Why is it so hard to express non-trivial C++ classes in D? Would it not be worth it to add some special annotations or something to express at least namespaces?

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• No operations allowed after statement closed issue

  - by Washu

  I have the next methods in my singleton to execute the JDBC connections public void openDB() throws ClassNotFoundException, IllegalAccessException, InstantiationException, SQLException { Class.forName("com.mysql.jdbc.Driver").newInstance(); String url = "jdbc:mysql://localhost/mbpe_peru";//mydb conn = DriverManager.getConnection(url, "root", "admin"); st = conn.createStatement(); } public void sendQuery(String query) throws SQLException { st.executeUpdate(query); } public void closeDB() throws SQLException { st.close(); conn.close(); } And I'm having a problem in a void where i have to call this twice. private void jButton1ActionPerformed(ActionEvent evt) { Main.getInstance().openDB(); Main.getInstance().sendQuery("call insertEntry('"+EntryID()+"','"+SupplierID()+"');"); Main.getInstance().closeDB(); Main.getInstance().openDB(); for(int i=0;i<dataBox.length;i++){ Main.getInstance().sendQuery("call insertCount('"+EntryID()+"','"+SupplierID()+"','"+BoxID()+"'); Main.getInstance().closeDB(); } } I have already tried to keep the connection open and send the 2 querys and after that closed and it didnt work... The only way it worked was to not use the methods, declare the commands for the connection and use different variables for the connection and the statement. I thought that if i close the Connecion and the Statement I could use the variable once again since is a method but I'm not able to. Is there any way to solve this using my methods for the JDBC connection?

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• Batch script is not executed if chcp was called

  - by Andy

  Hello! I'm trying to delete some files with unicode characters in them with batch script (it's a requirement). So I run cmd and execute: > chcp 65001 Effectively setting codepage to UTF-8. And it works: D:\temp\1>dir Volume in drive D has no label. Volume Serial Number is 8C33-61BF Directory of D:\temp\1 02.02.2010 09:31 <DIR> . 02.02.2010 09:31 <DIR> .. 02.02.2010 09:32 508 1.txt 02.02.2010 09:28 12 delete.bat 02.02.2010 09:20 95 delete.cmd 02.02.2010 09:13 <DIR> Rún 02.02.2010 09:13 <DIR> ????? ??????? 3 File(s) 615 bytes 4 Dir(s) 11 576 438 784 bytes free D:\temp\1>rmdir Rún D:\temp\1>dir Volume in drive D has no label. Volume Serial Number is 8C33-61BF Directory of D:\temp\1 02.02.2010 09:56 <DIR> . 02.02.2010 09:56 <DIR> .. 02.02.2010 09:32 508 1.txt 02.02.2010 09:28 12 delete.bat 02.02.2010 09:20 95 delete.cmd 02.02.2010 09:13 <DIR> ????? ??????? 3 File(s) 615 bytes 3 Dir(s) 11 576 438 784 bytes free Then I put the same rmdir commands in batch script and save it in UTF-8 encoding. But when I run nothing happens, literally nothing: not even echo works from batch script in this case. Even saving script in OEM encoding does not help. So it seems that when I change codepage to UTF-8 in console, scripts just stop working. Does somebody know how to fix that?

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• Parallel processing from a command queue on Linux (bash, python, ruby... whatever)

  - by mlambie

  I have a list/queue of 200 commands that I need to run in a shell on a Linux server. I only want to have a maximum of 10 processes running (from the queue) at once. Some processes will take a few seconds to complete, other processes will take much longer. When a process finishes I want the next command to be "popped" from the queue and executed. Does anyone have code to solve this problem? Further elaboration: There's 200 pieces of work that need to be done, in a queue of some sort. I want to have at most 10 pieces of work going on at once. When a thread finishes a piece of work it should ask the queue for the next piece of work. If there's no more work in the queue, the thread should die. When all the threads have died it means all the work has been done. The actual problem I'm trying to solve is using imapsync to synchronize 200 mailboxes from an old mail server to a new mail server. Some users have large mailboxes and take a long time tto sync, others have very small mailboxes and sync quickly.

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• Indexing/Performance strategies for vast amount of the same value

  - by DrColossos

  Base information: This is in context to the indexing process of OpenStreetMap data. To simplify the question: the core information is divided into 3 main types with value "W", "R", "N" (VARCHAR(1)). The table has somewhere around ~75M rows, all columns with "W" make up ~42M rows. Existing indexes are not relevant to this question. Now the question itself: The indexing of the data is done via an procedure. Inside this procedure, there are some loops that do the following: [...] SELECT * FROM table WHERE the_key = "W"; [...] The results get looped again and the above query itself is also in a loop. This takes a lot of time and slows down the process massivly. An indexon the_key is obviously useless since all the values that the index might use are the same ("W"). The script itself is running with a speed that is OK, only the SELECTing takes very long. Do I need to create a "special" kind of index that takes this into account and makes the SELECT quicker? If so, which one? need to tune some of the server parameters (they are already tuned and the result that they deliver seem to be good. If needed, I can post them)? have to live with the speed and simply get more hardware to gain more power (Tim Taylor grunt grunt)? Any alternatives to the above points (except rewriting it or not using it)?

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• Hibernate: fetching multiple bags efficiently

  - by Jens Jansson

  Hi! I'm developing a multilingual application. For this reason many objects have in their name and description fields collections of something I call LocalizedStrings instead of plain strings. Every LocalizedString is basically a pair of a locale and a string localized to that locale. Let's take an example an entity, let's say a book -object. public class Book{ @OneToMany private List<LocalizedString> names; @OneToMany private List<LocalizedString> description; //and so on... } When a user asks for a list of books, it does a query to get all the books, fetches the name and description of every book in the locale the user has selected to run the app in, and displays it back to the user. This works but it is a major performance issue. For the moment hibernate makes one query to fetch all the books, and after that it goes through every single object and asks hibernate for the localized strings for that specific object, resulting in a "n+1 select problem". Fetching a list of 50 entities produces about 6000 rows of sql commands in my server log. I tried making the collections eager but that lead me to the "cannot simultaneously fetch multiple bags"-issue. Then I tried setting the fetch strategy on the collections to subselect, hoping that it would do one query for all books, and after that do one query that fetches all LocalizedStrings for all the books. Subselects didn't work in this case how i would have hoped and it basically just did exactly the same as my first case. I'm starting to run out of ideas on how to optimize this. So in short, what fetching strategy alternatives are there when you are fetching a collection and every element in that collection has one or multiple collections in itself, which has to be fetch simultaneously.

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• Auto Submitting a form (cURL)

  - by cast01

  Im writing a form to post data off to paypal, and this works fine, i create the form with hidden fields and then have a submit button that submits everything to paypal. However, when the user clicks that button, there is more that i want to do, for example change their cart status in the database. So, i want to be able to execute some code when they click submit and then post the data to paypal. I dont want to use javascript for this. My method at the moment is using cURL, the form posts back to the current page, i then check for $_POST data, do my other commands like updating the status of the cart, and then create a curl command, and post the form data to paypal. Now, it gets posted successfully, but the browser doesnt go off to paypal. At first i was just retirieving the result in a string and then echoing it out and i could see that the post was successful, then i set CURLOPT_FOLLOWLOCATION to 1 assuming this would let the browser go off to paypal but it doesnt, what it seems to do is grab some stuff from paypal and put it on my page. Is using cURL the right thing for this? and if so, how do i get round this problem? I want to stay away from javascript for this as only users with javascript enabled would have their cart updated. The code im using for curl is below, the post_data is an array i created and then read key-value pairs into post_string. //Set cURL Options curl_setopt($curl_connection, CURLOPT_CONNECTTIMEOUT, 30); curl_setopt($curl_connection, CURLOPT_USERAGENT, "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)"); curl_setopt($curl_connection, CURLOPT_RETURNTRANSFER, false); curl_setopt($curl_connection, CURLOPT_SSL_VERIFYPEER, false); curl_setopt($curl_connection, CURLOPT_FOLLOWLOCATION, 1); curl_setopt($curl_connection, CURLOPT_MAXREDIRS, 20); //Set Data to be Posted curl_setopt($curl_connection, CURLOPT_POSTFIELDS, $post_string); //Execute Request curl_exec($curl_connection);

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• Having a problem inserting into database

  - by neo skosana

  I have a stored procedure: CREATE PROCEDURE busi_reg(IN instruc VARCHAR(10), IN tble VARCHAR(20), IN busName VARCHAR(50), IN busCateg VARCHAR(100), IN busType VARCHAR(50), IN phne VARCHAR(20), IN addrs VARCHAR(200), IN cty VARCHAR(50), IN prvnce VARCHAR(50), IN pstCde VARCHAR(10), IN nm VARCHAR(20), IN surname VARCHAR(20), IN eml VARCHAR(50), IN pswd VARCHAR(20), IN srce VARCHAR(50), IN refr VARCHAR(50), IN sess VARCHAR(50)) BEGIN INSERT INTO b_register SET business_name = busName, business_category = busCateg, business_type = busType, phone = phne, address = addrs, city = cty, province = prvnce, postal_code = pstCde, firstname = nm, lastname = surname, email = eml, password = pswd, source = srce, ref_no = refr; END; This is my php script: $busName = $_POST['bus_name']; $busCateg = $_POST['bus_cat']; $busType = $_POST['bus_type']; $phne = $_POST['phone']; $addrs = $_POST['address']; $cty = $_POST['city']; $prvnce = $_POST['province']; $pstCde = $_POST['postCode']; $nm = $_POST['name']; $surname = $_POST['lname']; $eml = $_POST['email']; $srce = $_POST['source']; $ref = $_POST['ref_no']; $result2 = $db->query("CALL busi_reg('$instruc', '$tble', '$busName', '$busCateg', '$busType', '$phne', '$addrs', '$cty', '$prvnce', '$pstCde', '$nm', '$surname', '$eml', '$pswd', '$srce', '$refr', '')"); if($result) { echo "Data has been saved"; } else { printf("Error: %s\n",$db->error); } Now the error that I get: Commands out of sync; you can't run this command now

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• JavaScript: why `null == 0` is false?

  - by lemonedo

  I had to write a routine that increments the value of a variable by 1 if it is a number, or assigns 0 to the variable if it is not a number. The variable can be incremented by the expression, or be assigned null. No other write access to the variable is allowed. So, the variable can be in three states: it is 0, a positive integer, or null. My first implementation was: v >= 0 ? v += 1 : v = 0 (Yes, I admit that v === null ? v = 0 : v += 1 is the exact solution, but I wanted to be concise then.) It failed since null >= 0 is true. I was confused, since if a value is not a number, an numeric expression involving it must be false always. Then I found that null is like 0, since null + 1 == 1, 1 / null == Infinity, Math.pow(2.718281828, null) == 1, ... Strangely enough, however, null == 0 is evaluated to false. I guess null is the only value that makes the following expression false: (v == 0) === (v >= 0 && v <= 0) So why null is so special in JavaScript?

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• In .NET, how do you send multiple arguments into a DOS command prompt?

  - by donde

  I am trying to execute DOS commands in ASP.NET 2.0. What I have now calls a BAT file which, in turn, calls a CMD file. It works (with the end result being a file gets ftp'ed). However, I'd like to dump the BAT and CMD files and run everything in .NET. What is the format of sending multiple arguments into the command window? Here is what I have now. The .NET Code: System.Diagnostics.Process proc = new System.Diagnostics.Process(); proc.EnableRaisingEvents = false; proc.StartInfo.FileName = "C:\\MyBat.BAT"; proc.Start(); proc.WaitForExit(); The Bat File looks like this (all it does is run the cmd file): ftp.exe -s:C:\MyCMD.cmd And here is the content of the Cmd file: open <my host> <my user name> <my pw> quote site cyl pri=1 sec=1 lrecl=1786 blksize=0 recfm=fb retpd=30 put C:\MyDTLFile.dtl 'MyDTLFile.dtl' quit

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• Efficient (basic) regular expression implementation for streaming data

  - by Brendan Dolan-Gavitt

  I'm looking for an implementation of regular expression matching that operates on a stream of data -- i.e., it has an API that allows a user to pass in one character at a time and report when a match is found on the stream of characters seen so far. Only very basic (classic) regular expressions are needed, so a DFA/NFA based implementation seems like it would be well-suited to the problem. Based on the fact that it's possible to do regular expression matching using a DFA/NFA in a single linear sweep, it seems like a streaming implementation should be possible. Requirements: The library should try to wait until the full string has been read before performing the match. The data I have really is streaming; there is no way to know how much data will arrive, it's not possible to seek forward or backward. Implementing specific stream matching for a couple special cases is not an option, as I don't know in advance what patterns a user might want to look for. For the curious, my use case is the following: I have a system which intercepts memory writes inside a full system emulator, and I would like to have a way to identify memory writes that match a regular expression (e.g., one could use this to find the point in the system where a URL is written to memory). I have found (links de-linkified because I don't have enough reputation): stackoverflow.com/questions/1962220/apply-a-regex-on-stream stackoverflow.com/questions/716927/applying-a-regular-expression-to-a-java-i-o-stream www.codeguru.com/csharp/csharp/cs_data/searching/article.php/c14689/Building-a-Regular-Expression-Stream-Search-with-the-NET-Framework.htm But all of these attempt to convert the stream to a string first and then use a stock regular expression library. Another thought I had was to modify the RE2 library, but according to the author it is architected around the assumption that the entire string is in memory at the same time. If nothing's available, then I can start down the unhappy path of reinventing this wheel to fit my own needs, but I'd really rather not if I can avoid it. Any help would be greatly appreciated!

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• Member function overloading/template specialization issue

  - by Ferruccio

  I've been trying to call the overloaded table::scan_index(std::string, ...) member function without success. For the sake of clarity, I have stripped out all non-relevant code. I have a class called table which has an overloaded/templated member function named scan_index() in order to handle strings as a special case. class table : boost::noncopyable { public: template <typename T> void scan_index(T val, std::function<bool (uint recno, T val)> callback) { // code } void scan_index(std::string val, std::function<bool (uint recno, std::string val)> callback) { // code } }; Then there is a hitlist class which has a number of templated member functions which call table::scan_index(T, ...) class hitlist { public: template <typename T> void eq(uint fieldno, T value) { table* index_table = db.get_index_table(fieldno); // code index_table->scan_index<T>(value, [&](uint recno, T n)->bool { // code }); } }; And, finally, the code which kicks it all off: hitlist hl; // code hl.eq<std::string>(*fieldno, p1.to_string()); The problem is that instead of calling table::scan_index(std::string, ...), it calls the templated version. I have tried using both overloading (as shown above) and a specialized function template (below), but nothing seems to work. After staring at this code for a few hours, I feel like I'm missing something obvious. Any ideas? template <> void scan_index<std::string>(std::string val, std::function<bool (uint recno, std::string val)> callback) { // code }

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• Centralizing Messagebox handling for application

  - by DRapp

  I'm wondering how others deal with trying to centralize MessageBox function calling. Instead of having long text embedded all over the place in code, in the past (non .net language), I would put system and application base "messagebox" type of messages into a database file which would be "burned" into the executable, much like a resource file in .Net. When a prompting condition would arise, I would just do call something like MBAnswer = MyApplication.CallMsgBox( IDUserCantDoThat ) then check the MBAnswer upon return, such as a yes/no/cancel or whatever. In the database table, I would have things like what the messagebox title would be, the buttons that would be shown, the actual message, a special flag that automatically tacked on a subsequent standard comment like "Please contact help desk if this happens.". The function would call the messagebox with all applicable settings and just return back the answer. The big benefits of this was, one location to have all the "context" of messages, and via constants, easier to read what message was going to be presented to the user. Does anyone have a similar system in .Net to do a similar approach, or is this just a bad idea in the .Net environment.

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• Debugging instance of another thread altering my data

  - by Mick

  I have a huge global array of structures. Some regions of the array are tied to individual threads and those threads can modify their regions of the array without having to use critical sections. But there is one special region of the array which all threads may have access to. The code that accesses these parts of the array needs to carefully use critical sections (each array element has its own critical section) to prevent any possibility of two threads writing to the structure simultaneously. Now I have a mysterious bug I am trying to chase, it is occurring unpredictably and very infrequently. It seems that one of the structures is being filled with some incorrect number. One obvious explanation is that another thread has accidentally been allowed to set this number when it should be excluded from doing so. Unfortunately it seems close to impossible to track this bug. The array element in which the bad data appears is different each time. What I would love to be able to do is set some kind of trap for the bug as follows: I would enter a critical section for array element N, then I know that no other thread should be able to touch the data, then (until I exit the critical section) set some kind of flag to a debugging tool saying "if any other thread attempts to change the data here please break and show me the offending patch of source code"... but I suspect no such tool exists... or does it? Or is there some completely different debugging methodology that I should be employing.

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