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• VirtualBox bridged network not working as expected

  - by iby chenko

  I am having hard time getting Bridged network to work with VirtualBox. Idea is to have host as well as one or more guests on same LAN. Using NAT (default) I do get access to internet and any node on the LAN when working from one of the VM guests. However, no LAN node including host can access (or ping) guest in VM. I need to be able to use any guest as if it was a physical computer on the network (need to be accessed by any machine on LAN). According to my understanding of the VirtualBox documentation, this should be Bridged mode. I think I set it correctly, well, actually there is not much to it: 1. select Bridged mode in VM network setup 2. select physical NIC of the host to connect bridge to 3. start VM When I do this, each VM does get new IP address that corresponds to LAN settings : 192.168.1.100 192.168.1.102 192.168.1.103 etc. where host is 192.168.1.80 / 255.255.255.0 (IP addresses above 100 are served by DHCP server). This seem to be correct based on what I know about ethernet. From VM I can ping other nodes like 192.168.1.50 etc. and I still get ethernet access. So far so good... But I STILL cannot ping any of the other VMs (running ones of course). I cannot ping them from other VMs, from host or from other nodes on the LAN. Aside from fact that IP addresses handed to guests are now local, this still acts same as NAT. What is going on? What am I missing? Regards, I

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• Set up layer 2 vlan between 2 data centres

  - by user41679

  Hello, Our data centre provider operates 2 sites, and we currently have equipment in one and would like to have equipment in the second. They've told me that they operate a layer 2 vlan between the 2 sites over a 20gbit connection, and that they'd just give me ethernet cable at each end to connect the locations. At the current site, we have Cisco 2960 48TC-L switches, all the machines are on a 192.168.x.x subnet and we have cisco firewalls with which we connect to our internet provider with. My question is what would I need to do to connect the 2 sites? could I just plug the ethernet cables the provide into the cisco switches, and have the same switches the other end? would I need to set up a separate internal network on the other side and connect both through the firewalls? Would the cisco switches need special configuration? We expect to maintain a number of connections between the 2 sites, and each site would have its own internal dns name like dc1.xx.com. Sorry if I'm being vague or haven't included enough information, I've a fairly good knowledge of hardware but we're down a netops guy at the moment and I'd like to get both sites on-line ASAP! Thanks in advance!

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• Binding TabControl ItemsSource to an ObservableCollection causes content to refresh on focus

  - by Brent

  I'm creating an WPF application using the MVVM framework, and I've adopted several features from Josh Smith's article on MVVM here... Most importantly, I'm binding a TabControl to an ObservableCollection of ViewModels. This means that am using a tabbed MDI interface that displays a UserControl as the content of a TabItem. The issue I'm seeing in my application is that when I have several tabs and I flip back and forth between tabs, the content is being refersh each time I change tabs. If you download Josh Smith's source code, you'll see that his app has the same problem. For example, click on the "View All Customers" button and scroll down to the bottom the ListView. Next click on the "Create New Customer" button. When you switch back to the All Customer view you'll notice that the ListView scrolls back to the top. If you switch back to the New Customer tab and place your cursor in one of the TextBoxes, then switch to All Customers tab and back, you'll notice that the cursor is now gone. I imagine that this is because I'm using an ObservableCollection, but I can't be sure. Is there any way to prevent the tab's content from refreshing when it receives the focus?

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• Strange options menu behavior in Android TabActivity

  - by jboxer

  I have a TabActivity with four tabs (each is its own Activity). Each tab defines its own onCreateOptionsMenu (and in some cases, onPrepareOptionsMenu). When each tab is loaded, an AsyncTask is kicked off to retrieve the data needed to populate that tab's list. If I switch between tabs very quickly (while they're still loading) and then press the menu button (while the current tab's AsyncApiTask is still running), I'm able to get the wrong options menu to appear. For example, let's say FooActivity (tab 1) has an options menu with a "Refresh" item, and BarActivity (tab 2) has an options menu with a "View All" item. If I start the app (with tab 1 active), quickly switch to tab 2, and then hit menu, the "Refresh" item (rather than the expected "View All" item) will sometimes show. Furthermore, while this weird behavior sometimes occurs just on the first menu press (and later presses show the right items), sometimes it gets "stuck", and the wrong items show up on every press until I switch tabs. Any idea what could be going on? I haven't heard of this happening before, and haven't been able to find any good suggestions.

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• monitoring iphone 3g/wifi bandswitch

  - by user262325

  Hello everyone I hope add the function to monitor iphone used 3g/wifi band switch. I know I can do these in my app, but I wonder if there is way to monitor all band switch usage of iPhone? I noticed that there is an app http://itunes.apple.com/ca/app/download-meter-for-wi-fi-gprs/id327227530?mt=8 It claims: Works with any carrier (iPods are supported too!). Requires no login/password to your carrier's site. Does not require Internet connection to get traffic usage statistics (works even in Airplane mode) because it gets information on traffic from the device, not a carrier; this means it won't cost you anything to view current traffic consumed, even while roaming in a location where traffic is very expensive. Allows the user to adjust consumed traffic for today or the current month to match traffic amounts reported by your carrier. Stats on the screen are updated every second. Measures traffic in real time with up to byte precision. Separates traffic into incoming and outgoing, Wi-Fi traffic and mobile Internet traffic. It looks like it gets the band switch info from carrier site, but they also said it gets info from device. I am really confused. Welcome any comment. Thanks interdev

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• jquery tab switching links so they jump to top of page?

  - by Evan

  I was given some great help by redsquare to get this far to change jquery tabs from links within the content, but I have one more issue that I'm looking for support on... When a user clicks a link to switch to a different tab from within the content, can i get the page to jump to the top of the page? Within my demo link, scroll to the bottom of the page to click the links and they switch tabs just perfectly, which you can confirm if you scroll up. So, I'm looking for the switch to also jump the user to the top of the page, so the user doesn't have to "scroll" to the top of the page to begin reading new content. Here's my demo: http://jsbin.com/etoku3/11 Existing code: <script type="text/javascript"> $(document).ready(function() { var $tabs = $("#container-1").tabs(); var changeTab = function(ev){ ev.preventDefault(); var tabIndex = this.hash.charAt(this.hash.length-1) -1; $tabs.tabs('select', tabIndex); }; $('a.tablink').click(changeTab); }); </script> Thank you so much! Evan

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• Question about 'git branching'

  - by michael

  Hi, I read this about git branch: http://book.git-scm.com/3_basic_branching_and_merging.html so I follow it and create 1 branch : experimental And I 1. switch to experimental branch (git checkout experimental) 2. make a bunch of changes 3. commit it (git commit -a) 4. switch to master branch (git checkout master) 5. make some changes and commit there 6. switch back to experimental (git checkout experimental) 7. merge master change to experimental (git merge master) 8. there are some conflicts but after I resolve them, I did 'git add myfile' And now i am stuck, I can't move back to master when I do $ git checkout master error: Entry 'res/layout/my_item.xml' would be overwritten by merge. Cannot merge. and I did: $ git rebase --abort No rebase in progress? and I did : $ git add res/layout/socialhub_list_item.xml $ git checkout master error: Entry 'res/layout/my_item.xml' would be overwritten by merge. Cannot merge. What can I do so that I can go back to my master branch? Thank you.

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• Testing background audio in the simulator

  - by Cactuar

  I'm experimenting with the new background audio service in iPhone OS 4.0 but I can't get it to work in the simulator. According to this page: iPhone Application Programming Guide: Executing Code in the Background it seems that all I have to do is add the a UIBackgroundModes key with an array containing audio to my Info.plist file and the audio my application plays should automatically continue when I switch to another app. I have done this but the audio still pauses as I switch to another app, when I switch back it continues where it left off. This is the code I'm using to play the sound: NSURL *url = [NSURL fileURLWithPath:[NSString stringWithFormat:@"%@/audio.mp3", [[NSBundle mainBundle] resourcePath]]]; NSError *error; audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:&error]; audioPlayer.numberOfLoops = -1; if (audioPlayer == nil) NSLog(@"%@", [error userInfo]); else [audioPlayer play]; Has anyone gotten this to work? Could it be that it would work on an actual device and it's just a problem with the simulator? I'm a bit hesitant to install 4.0 on my phone since I've heard it's still very buggy. Wish I had another device to use only for development.

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• php - disconnecting and connecting to multiple databases

  - by Phil Jackson

  Hi, I want to be able to switch from the current db to multiple dbs though a loop: $query = mysql_query("SELECT * FROM `linkedin` ORDER BY id", $CON ) or die( mysql_error() ); if( mysql_num_rows( $query ) != 0 ) { $last_update = time() / 60; while( $rows = mysql_fetch_array( $query ) ) { $contacts_db = "NNJN_" . $rows['email']; // switch to the contacts db mysql_select_db( $contacts_db, $CON ); $query = mysql_query("SELECT * FROM `linkedin` WHERE token = '" . TOKEN . "'", $CON ) or die( mysql_error() ); if( mysql_num_rows( $query ) != 0 ) { mysql_query("UPDATE `linkedin` SET last_update = '{$last_update}' WHERE token = '" . TOKEN . "'", $CON ) or die( mysql_error() ); }else{ mysql_query("INSERT INTO `linkedin` (email, token, username, online, away, last_update) VALUES ('" . EMAIL . "', '" . TOKEN . "', '" . USERNAME . "', 'true', 'false', '$last_update')", $CON ) or die( mysql_error() ); } } mysql_free_result( $query ); } // switch back to your own mysql_select_db( USER_DB, $CON ); It does insert and update details from the other databases but it also inserts and edits data from the current users database which I dont want. Any ideas?

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• How to remove all ListBox items?

  - by Nano HE

  Hi, I created two RadioButton (Weight and Height). I will do switch between the two categories. But the they share the same ListBox Controllers (listBox1 and listBox2). Is there any good method to clear all the ListBox items simpler? I didn't find the removeAll() for ListBox. I don't like my complex multi-lines style which I posted here. private void Weight_Click(object sender, RoutedEventArgs e) { // switch between the radioButton "Weith" and "Height" // Clear all the items first listBox1.Items.Remove("foot"); listBox1.Items.Remove("inch"); listBox1.Items.Remove("meter"); listBox2.Items.Remove("foot"); listBox2.Items.Remove("inch"); listBox2.Items.Remove("meter"); // Add source units items for listBox1 listBox1.Items.Add("kilogram"); listBox1.Items.Add("pound"); // Add target units items for listBox2 listBox2.Items.Add("kilogram"); listBox2.Items.Add("pound"); } private void Height_Click(object sender, RoutedEventArgs e) { // switch between the radioButton "Weith" and "Height" // Clear all the items first listBox1.Items.Remove("kilogram"); listBox1.Items.Remove("pound"); listBox2.Items.Remove("kilogram"); listBox2.Items.Remove("pound"); // Add source units items for listBox1 listBox1.Items.Add("foot"); listBox1.Items.Add("inch"); listBox1.Items.Add("meter"); // Add target units items for listBox2 listBox2.Items.Add("foot"); listBox2.Items.Add("inch"); listBox2.Items.Add("meter"); }

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• Building an *efficient* if/then interface for non-technical users to build flow-control in PHP

  - by Brendan

  I am currently building an internal tool to be used by our management to control the flow of traffic. I have built an if/then interface allowing the user to set conditions for certain outcomes, however it is inefficient to use the switch statement to control the flow. How can I improve the efficiency of my code? Example of code: if($previous['route_id'] == $condition['route_id'] && $failed == 0) //if we have not moved on to a new set of rules and we haven't failed yet { switch($condition['type']) { case 0 : $type = $user['hour']; break; case 1 : $type = $user['location']['region_abv']; break; case 2 : $type = $user['referrer_domain']; break; case 3 : $type = $user['affiliate']; break; case 4 : $type = $user['location']['country_code']; break; case 5 : $type = $user['location']['city']; break; } $type = strtolower($type); $condition['value'] = strtolower($condition['value']); switch($condition['operator']) { case 0 : if($type == $condition['value']); else $failed = '1'; break; case 1 : if($type != $condition['value']); else $failed = '1'; break; case 2 : if($type > $condition['value']); else $failed = '1'; break; case 3 : if($type >= $condition['value']); else $failed = '1'; break; case 4 : if($type < $condition['value']); else $failed = '1'; break; case 5 : if($type <= $condition['value']); else $failed = '1'; break; } }

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• How can I load a view based on how long I hold a UIButton?

  - by Thomas

  Hello all, I've searched the net and documentation, but haven't found anything quite like what I'm trying to do. I'm working on an app where I want to load one view if a UIButton is held for x seconds, another if it's held for x+y seconds, etc. I found this tutorial. The problem I'm running into is, how do I switch the length of the button press? The tutorial switched the number of taps. -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { NSSet *allTouches = [event allTouches]; switch ([allTouches count]) { case 1: // Single touch { // Get the first touch. UITouch *touch = [[allTouches allObjects] objectAtIndex:0]; switch ([touch tapCount]) { case 1: // Single Tap. { // Start a timer timer = [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:@selector(showAlertView:) userInfo:nil repeats:NO]; [timer retain]; } break; case 2: // Double tap. break; } } break; case 2: // Double touch { } break; default: break; } } Any suggestions? Thanks! Thomas

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• What is the general feeling about reflection extensions in std::type_info?

  - by Evan Teran

  I've noticed that reflection is one feature that developers from other languages find very lacking in c++. For certain applications I can really see why! It is so much easier to write things like an IDE's auto-complete if you had reflection. And certainly serialization APIs would be a world easier if we had it. On the other side, one of the main tenets of c++ is don't pay for what you don't use. Which makes complete sense. That's something I love about c++. But it occurred to me there could be a compromise. Why don't compilers add extensions to the std::type_info structure? There would be no runtime overhead. The binary could end up being larger, but this could be a simple compiler switch to enable/disable and to be honest, if you are really concerned about the space savings, you'll likely disable exceptions and RTTI anyway. Some people cite issues with templates, but the compiler happily generates std::type_info structures for template types already. I can imagine a g++ switch like -fenable-typeinfo-reflection which could become very popular (and mainstream libs like boost/Qt/etc could easily have a check to generate code which uses it if there, in which case the end user would benefit with no more cost than flipping a switch). I don't find this unreasonable since large portable libraries like this already depend on compiler extensions. So why isn't this more common? I imagine that I'm missing something, what are the technical issues with this?

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• Array Recursion

  - by GeeYouAreYou

  I've got an assignment I can't figure out, any pointers will be much appreciated, it goes like so: There's a series of light bulbs represented as an array of true/false, there's a switch for every light bulb, by clicking it for any light bulb, you toggle it as well as 2 adjacent ones (1 from left & another 1 from right; if clicked switch's bulb on edge -- only 1 adjacent toggled of course). What is needed to accomplish is a method that accepts an array of a series of turned on/off light bulbs and another one representing another state of supposedly the 1st array after some switches have been clicked..! So recursion must be used to find out whether there's a combination of switch clicks that will transform array 1 to array 2. Here's the signature of the method: public static boolean disco(boolean[] init, boolean[] target) Will return true if array init can be transformed to target, false otherwise. Method must be static and not use any other static and global variables, only local. Example: boolean[] init = {true, false, true, false, true, false}; boolean[] target = {false, true, false, true, false, true}; For above 2 arrays, disco(init, target) will return true because toggling the 1st and 4th bulbs would yield the target state (remember adjacent bulbs being toggled as well). Any help much appreciated..!!

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• Silverlight MVVM binding seems not to work

  - by Savvas Sopiadis

  Hi everybody! Building my first SL MVVM application (Silverlight4 RC) and have some issues i don't understand. Having a WPF background i don't know what is going on here: ViewModel has several properties, in which one is called SelectedRecord. This is a get only property and is defined like this: public Culture SelectedRecord { get { return culturesView.View.CurrentItem as Culture; } } As you can see it is gets the current value of a CollectionViewSource (called culturesView). So if i select a Culture, the SelectedRecord (gets a value directly from within the CollectionViewSource) as expected. (Actually there is a datagrid control bound to the CollectionViewSource, hence it is possible to change the selected item) OK. Now to the View . There are several views which access this ViewModel and in particular there is one which shows the values of the aforementioned property SelectedRecord (let's call it the EditView). To show this EditView there is a button (which has its Command property bound to an ICommand in the ViewModel) which functions (the first time) as expected. This means: 1st try : i select a record, switch to EditView, outcome: selected record values are shown (as expected!!). 2nd try: switch back to datagrid, select another record, switch to EditView, outcome: the values of the previous shown record are shown again!!! WHY?? First i thought that the SelectedRecord has not the correct value set, but i was mistaken: it HAS the correct value! So it should be shown!? What am i missing? In WPF this would work!! Thanks in advance

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• Website often sticks, but clicking the link again everything loads fine

  - by Dave

  Hi I have a website, which normally is very fast, however in the last week or two we're run into a problem whereby randomly if you click a link the browser will just sit there with the throbber spinning but the page doesn't appear to load If you click the link again it then responds straight away This doesn't seem to be limited to Chrome, Firefox or IE as we've tried all with all having same problems The site is build in ASP and connects to a MySQL database and runs on a dedicated windows 2003 server The firewalls were changed in the data centre recently to pixies but I've not been able to reproduce the problem outside of the office Within the office, we have 11 people (only 7 today and still experiencing problems) connected to a 7MB ADSL connection with Eclipse I have made some changes to the network in the office, namely wiring 4 desks back to the main 24 port switch rather than to small 5 port which then linked on to the 24 port switch... however we were having problems before this was done, and I did this to try and rule out an issue with the switch We have a backup ADSL connection, so I may try switching to that, or switching to a different router, but do you think this is a likely issue? Failing that, what else would you check? Thanks, sorry for length! Dave

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• How to get NEW width/height of root layout in onConfigurationChanged?

  - by jboxer

  One of our views has a ScrollView as its root layout. When the device is rotated and onConfigurationChanged() is called, we'd like to be able to get the ScrollView's new width/height. Our code looks like this: @Override public void onConfigurationChanged(Configuration newConfig) { Log.d(TAG, "Width: '" + findViewById(R.id.scrollview).getWidth() + "'"); Log.d(TAG, "Height: '" + findViewById(R.id.scrollview).getHeight() + "'"); super.onConfigurationChanged(newConfig); Log.d(TAG, "Width: '" + findViewById(R.id.scrollview).getWidth() + "'"); Log.d(TAG, "Height: '" + findViewById(R.id.scrollview).getHeight() + "'"); } And the relevant section of our AndroidManifest.xml looks like this: <activity android:name=".SomeActivity" android:configChanges="keyboardHidden|orientation"> <intent-filter> <action android:name="android.intent.action.MAIN" /> </intent-filter> </activity> On our Droid, we expected to see the ScrollView's width go to 854 when switched into landscape, and to 480 when switched back to portrait (and the height do the equivalent switch, minus the menu bar). However, we're seeing the opposite. Here's our LogCat: // Switching to landscape: 03-26 11:26:16.490: DEBUG/ourtag(17245): Width: '480' // Before super 03-26 11:26:16.490: DEBUG/ourtag(17245): Height: '778' // Before super 03-26 11:26:16.529: DEBUG/ourtag(17245): Width: '480' // After super 03-26 11:26:16.536: DEBUG/ourtag(17245): Height: '778' // After super // Switching to portrait: 03-26 11:26:28.724: DEBUG/ourtag(17245): Width: '854' // Before super 03-26 11:26:28.740: DEBUG/ourtag(17245): Height: '404' // Before super 03-26 11:26:28.740: DEBUG/ourtag(17245): Width: '854' // After super 03-26 11:26:28.740: DEBUG/ourtag(17245): Height: '404' // After super Clearly, we're getting the portrait dimensions when we switch to landscape, and the landscape dimensions when we switch to portrait. Is there something we're doing wrong? We could get hacky and solve this, but I feel like there's a simple solution that we're missing.

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• Efficient Clojure workflow?

  - by Alex B

  I am developing a pet project with Clojure, but wonder if I can speed up my workflow a bit. My current workflow (with Compojure) is: Start Swank with lein swank. Go to Emacs, connect with M-x slime-connect. Load all existing source files one by one. This also starts a Jetty server and an application. Write some code in REPL. When satisfied with experiments, write a full version of a construct I had in mind. Eval (C-c C-c) it. Switch REPL to namespace where this construct resides and test it. Switch to browser and reload browser tab with the affected page. Tweak the code, eval it, check in the browser. Repeat any of the above. There are a number of annoyances with it: I have to switch between Emacs and the browser (or browsers if I am testing things like templating with multiple browsers) all the time. Is there a common idiom to automate this? I used to have a JavaScript bit that reloads the page continuously, but it's of limited utility, obviously, when I have to interact with the page for more than a few seconds. My JVM instance becomes "dirty" when I experiment and write test functions. Basically namespaces become polluted, especially if I'm refactoring and moving the functions between namespaces. This can lead to symbol collisions and I need to restart Swank. Can I undef a symbol? I load all source files one by one (C-c C-k) upon restarting Swank. I suspect I'm doing it all wrong. Switching between the REPL and the file editor can be a bit irritating, especially when I have a lot of Emacs tabs open, alongside the browser(s). I'm looking for ways to improve the above points and the entire workflow in general, so I'd appreciate if you'd share yours. P. S. I have also used Vimclojure before, so Vimclojure-based workflows are welcome too.

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• movie does not start in full screen in flash video player

  - by jodeci

  We have this legacy code of a flash video player that functions well enough but still has some loose ends I need to tighten up. It can do the basic "switch to full screen and back to normal size" stunts, however with one exception. On the first fresh load of the app, if I switch to full screen mode first, and then click to play the movie, the player would be in full screen, yet the movie itself would remain in it's original size. //trigger if (stage.displayState == StageDisplayState.NORMAL) { stage.addEventListener('fullScreen', procFullScreen); stage.scaleMode = StageScaleMode.NO_SCALE; stage.displayState = StageDisplayState.FULL_SCREEN; //mv:VideoDisplay mv.percentHeight = 100; mv.percentWidth = 100; mv.x = 0; mv.y = 0; } // event handler if (event.fullScreen) { mv.smoothing = true; this.height = stage.height; this.width = stage.width; //videoCanvas:Canvas videoCanvas.height = Application.application.height; videoCanvas.width = Application.application.width; fullScreenViewStack.selectedIndex = 1; } The VideoDisplay object even returns the expected width/height, but the movie just plays in it's original size. If I switch screen sizes during movie playback, then the movie size will shrink or stretch as it should. I'm running out of ideas, any suggestions? Thanks in advance!

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• XML/RDF to Java Objects with XSD

  - by bmucklow

  So here's the scenario...I have an XSD file describing all the objects that I need. I can create the objects in Java using JAXB no problem. I have an XML/RDF file that I need to parse into those objects. What is the EASIEST way to do this? I have been looking into Jena and have played around with it, but can't see how to easily map the XML/RDF file to the XSD objects that were generated. Here is a snippet of the XSD file as well as the XML/RDF file: <?xml version="1.0" encoding="UTF-8"?> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:a="http://langdale.com.au/2005/Message#" xmlns:sawsdl="http://www.w3.org/ns/sawsdl" targetNamespace="http://iec.ch/TC57/2007/profile#" elementFormDefault="qualified" attributeFormDefault="unqualified" xmlns="http://langdale.com.au/2005/Message#" xmlns:m="http://iec.ch/TC57/2007/profile#"> <xs:annotation/> <xs:element name="Profile" type="m:Profile"/> <xs:complexType name="Profile"> <xs:sequence> <xs:element name="Breaker" type="m:Breaker" minOccurs="0" maxOccurs="unbounded"/> And the XML/RDF: <!-- CIM XML Output For switch783:(295854688) --> <cim:Switch rdf:ID="Switch_295854688"> <cim:IdentifiedObject.mRID>Switch_295854688</cim:IdentifiedObject.mRID> <cim:IdentifiedObject.aliasName>Switch_295854688</cim:IdentifiedObject.aliasName> <cim:ConductingEquipment.phases rdf:resource="http://iec.ch/TC57/2009/CIM-schema-cim14#PhaseCode.ABC" /> <cim:Switch.circuit2>0001406</cim:Switch.circuit2> <cim:Equipment.Line rdf:resource="#Line_0001406" />

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• Alignment in assembly

  - by jena

  Hi, I'm spending some time on assembly programming (Gas, in particular) and recently I learned about the align directive. I think I've understood the very basics, but I would like to gain a deeper understanding of its nature and when to use alignment. For instance, I wondered about the assembly code of a simple C++ switch statement. I know that under certain circumstances switch statements are based on jump tables, as in the following few lines of code: .section .rodata .align 4 .align 4 .L8: .long .L2 .long .L3 .long .L4 .long .L5 ... .align 4 aligns the following data on the next 4-byte boundary which ensures that fetching these memory locations is efficient, right? I think this is done because there might be things happening before the switch statement which caused misalignment. But why are there actually two calls to .align? Are there any rules of thumb when to call .align or should it simply be done whenever a new block of data is stored in memory and something prior to this could have caused misalignment? In case of arrays, it seems that alignment is done on 32-byte boundaries as soon as the array occupies at least 32 byte. Is it more efficient to do it this way or is there another reason for the 32-byte boundary? I'd appreciate any explanation or hint on literature.

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• protocol parsing in c

  - by nomad.alien

  I have been playing around with trying to implement some protocol decoders, but each time I run into a "simple" problem and I feel the way I am solving the problem is not optimal and there must be a better way to do things. I'm using C. Currently I'm using some canned data and reading it in as a file, but later on it would be via TCP or UDP. Here's the problem. I'm currently playing with a binary protocol at work. All fields are 8 bits long. The first field(8bits) is the packet type. So I read in the first 8 bits and using a switch/case I call a function to read in the rest of the packet as I then know the size/structure of it. BUT...some of these packets have nested packets inside them, so when I encounter that specific packet I then have to read another 8-16 bytes have another switch/case to see what the next packet type is and on and on. (Luckily the packets are only nested 2 or 3 deep). Only once I have the whole packet decoded can I handle it over to my state machine for processing. I guess this can be a more general question as well. How much data do you have to read at a time from the socket? As much as possible? As much as what is "similar" in the protocol headers? So even though this protocol is fairly basic, my code is a whole bunch of switch/case statements and I do a lot of reading from the file/socket which I feel is not optimal. My main aim is to make this decoder as fast as possible. To the more experienced people out there, is this the way to go or is there a better way which I just haven't figured out yet? Any elegant solution to this problem?

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• gcc -finline-functions behaviour?

  - by user176168

  I'm using gcc with the -finline-functions optimization for release builds. In order to combat code bloat because I work on an embedded system I want to say don't inline particular functions. The obvious way to do this would be through function attributes ie attribute(noinline). The problem is this doesn't seem to work when I switch on the global -finline-functions optimisation which is part of the -O3 switch. It also has something to do with it being templated as a non templated version of the same function doesn't get inlined which is as expected. Has anybody any idea of how to control inlining when this global switch is on? Here's the code: #include <cstdlib> #include <iostream> using namespace std; class Base { public: template<typename _Type_> static _Type_ fooT( _Type_ x, _Type_ y ) __attribute__ (( noinline )); }; template<typename _Type_> _Type_ Base::fooT( _Type_ x, _Type_ y ) { asm(""); return x + y; } int main(int argc, char *argv[]) { int test = Base::fooT( 1, 2 ); printf( "test = %d\n", test ); system("PAUSE"); return EXIT_SUCCESS; }

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• anti-if campaign

  - by Andrew Siemer

  I recently ran against a very interesting site that expresses a very interesting idea - the anti-if campaign. You can see this here at www.antiifcampaign.com. I have to agree that complex nested IF statements are an absolute pain in the rear. I am currently on a project that up until very recently had some crazy nested IFs that scrolled to the right for quite a ways. We cured our issues in two ways - we used Windows Workflow Foundation to address routing (or workflow) concerns. And we are in the process of implementing all of our business rules utilizing ILOG Rules for .NET (recently purchased by IBM!!). This for the most part has cured our nested IF pains...but I find myself wondering how many people cure their pains in the manner that the good folks at the AntiIfCampaign suggest (see an example here) by creating numerous amounts of abstract classes to represent a given scenario that was originally covered by the nested IF. I wonder if another way to address the removal of this complexity might also be in using an IoC container such as StructureMap to move in and out of different bits of functionality. Either way... Question: Given a scenario where I have a nested complex IF or SWITCH statement that is used to evaluate a given type of thing (say evaluating an Enum) to determine how I want to handle the processing of that thing by enum type - what are some ways to do the same form of processing without using the IF or SWITCH hierarchical structure? public enum WidgetTypes { Type1, Type2, Type3, Type4 } ... WidgetTypes _myType = WidgetTypes.Type1; ... switch(_myType) { case WidgetTypes.Type1: //do something break; case WidgetTypes.Type2: //do something break; //etc... }

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• GUI blocked while running silent app VC++

  - by deb

  Hi, I have built a GUI interface in C++ (Windows XP, visual c++ 2008). There you can configure some parameters and when I click on the OK button, a silent application is launched (and uses the values setted). When I do this, the GUI frozes and even dissappears if you switch to other windows(it's still there, but you can only see a white space), when the other application's finished the GUI works again. This is the correct behaviour, I don't want the user to be able to edit the fields... but it's a bit ugly when you can't see the GUI. Does anybody know an easy way of being able to switch to other windows and being able to see the the GUI when you switch back? Thanks in advance Edited: Hi, I tried doing this, but the problem is that to run the apps in background I had a function that uses CreateProcess. So both ways the GUI gets frozen: if I create a Thread that creates the process and if I creathe the process directly. Then I wait for the process to finish: if (!CreateProcess( NULL, Args, NULL, NULL, FALSE, CREATE_NEW_CONSOLE, NULL, NULL, &StartupInfo, &ProcessInfo)) { return GetLastError(); } WaitForSingleObject(ProcessInfo.hProcess, INFINITE); if(!GetExitCodeProcess(ProcessInfo.hProcess, &rc)) rc = 0; Any idea?

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