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  • Network communication for a turn based board game

    - by randooom
    Hi all, my first question here, so please don't be to harsh if something went wrong :) I'm currently a CS student (from Germany, if this info is of any use ;) ) and we got a, free selectable, programming assignment, which we have to write in a C++/CLI Windows Forms Application. My team, two others and me, decided to go for a network-compatible port of the board game Risk. We divided the work in 3 Parts, namely UI, game logic and network. Now we're on the part where we have to get everything working together and the big question mark is, how to get the clients synchronized with each other? Our approach so far is, that each client has all information necessary to calculate and/or execute all possible actions. Actually the clients have all information available at all, aside from the game-initializing phase (add players, select map, etc.), which needs one "super-client" with some extra stuff to control things. This is the standard scenario of our approach: player performs action, the action is valid and got executed on the players client action is sent over the network action is executed on the other clients The design (i.e. no or code so far) we came up with so far, is something like the following pseudo sequence diagram. Gui, Controller and Network implement all possible actions (i.e. all actions which change data) as methods from an interface. So each part can implement the method in a way to get their job done. Example with Action(): On the player side's Client: Player-->Gui.Action() Gui-->Controller.Action() Controller-->Logic.Action (Logic.Action() == NoError)? Controller-->Network.Action() Network-->Parser.ParseAction() Network.Send(msg) On all other clients: Network.Recv(msg) Network-->Parser.Deparse(msg) Parser-->Logic.Action() Logic-->Gui.Action() The questions: Is this a viable approach to our task? Any better/easier way to this? Recommendations, critique? Our knowledge (so you can better target your answer): We are on the beginner side, in regards to programming on a somewhat larger projects with a small team. All of us have some general programming experience and basic understanding of the .Net Libraries and Windows Forms. If you need any further information, please feel free to ask.

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  • Regular expression works normally, but fails when placed in an XML schema

    - by Eli Courtwright
    I have a simple doc.xml file which contains a single root element with a Timestamp attribute: <?xml version="1.0" encoding="utf-8"?> <root Timestamp="04-21-2010 16:00:19.000" /> I'd like to validate this document against a my simple schema.xsd to make sure that the Timestamp is in the correct format: <?xml version="1.0" encoding="utf-8"?> <xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xs:element name="root"> <xs:complexType> <xs:attribute name="Timestamp" use="required" type="timeStampType"/> </xs:complexType> </xs:element> <xs:simpleType name="timeStampType"> <xs:restriction base="xs:string"> <xs:pattern value="(0[0-9]{1})|(1[0-2]{1})-(3[0-1]{1}|[0-2]{1}[0-9]{1})-[2-9]{1}[0-9]{3} ([0-1]{1}[0-9]{1}|2[0-3]{1}):[0-5]{1}[0-9]{1}:[0-5]{1}[0-9]{1}.[0-9]{3}" /> </xs:restriction> </xs:simpleType> </xs:schema> So I use the lxml Python module and try to perform a simple schema validation and report any errors: from lxml import etree schema = etree.XMLSchema( etree.parse("schema.xsd") ) doc = etree.parse("doc.xml") if not schema.validate(doc): for e in schema.error_log: print e.message My XML document fails validation with the following error messages: Element 'root', attribute 'Timestamp': [facet 'pattern'] The value '04-21-2010 16:00:19.000' is not accepted by the pattern '(0[0-9]{1})|(1[0-2]{1})-(3[0-1]{1}|[0-2]{1}[0-9]{1})-[2-9]{1}[0-9]{3} ([0-1]{1}[0-9]{1}|2[0-3]{1}):[0-5]{1}[0-9]{1}:[0-5]{1}[0-9]{1}.[0-9]{3}'. Element 'root', attribute 'Timestamp': '04-21-2010 16:00:19.000' is not a valid value of the atomic type 'timeStampType'. So it looks like my regular expression must be faulty. But when I try to validate the regular expression at the command line, it passes: >>> import re >>> pat = '(0[0-9]{1})|(1[0-2]{1})-(3[0-1]{1}|[0-2]{1}[0-9]{1})-[2-9]{1}[0-9]{3} ([0-1]{1}[0-9]{1}|2[0-3]{1}):[0-5]{1}[0-9]{1}:[0-5]{1}[0-9]{1}.[0-9]{3}' >>> assert re.match(pat, '04-21-2010 16:00:19.000') >>> I'm aware that XSD regular expressions don't have every feature, but the documentation I've found indicates that every feature that I'm using should work. So what am I mis-understanding, and why does my document fail?

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  • Streaming webcam video in Flash using MP4 encoding

    - by Herms
    One of the features of the Flash app I'm working on is to be able to stream a webcam to others. We're just using the built-in webcam support in Flash and sending it through FMS. We've had some people ask for higher quality video, but we're already using the highest quality setting we can in Flash (setting quality to 100%). My understanding is that in the newer flash players they added support for MPEG-4 encoding for the videos. I created a simple test Flex app to try and compare the video quality of the MP4 vs FLV encodings. However, I can't seem to get MP4 to work at all. According to the Flex documentation the only thing I need to do to use MP4 instead of FLV is prepend "mp4:" to the name of the stream when calling publish: Specify the stream name as a string with the prefix mp4: with or without the filename extension. The prefix indicates to the server that the file contains H.264-encoded video and AAC-encoded audio within the MPEG-4 Part 14 container format. When I try this nothing happens. I don't get any events raised on the client side, no exceptions thrown, and my logging on the server side doesn't show any streams starting. Here's the relevant code: // These are all defined and created within the class. private var nc:NetConnection; private var sharing:Boolean; private var pubStream:NetStream; private var format:String; private var streamName:String; private var camera:Camera; // called when the user clicks the start button private function startSharing():void { if (!nc.connected) { return; } if (sharing) { return; } if(pubStream == null) { pubStream = new NetStream(nc); pubStream.attachCamera(camera); } startPublish(); sharing = true; } private function startPublish():void { var name:String; if (this.format == "mp4") { name = "mp4:" + streamName; } else { name = streamName; } //pubStream.publish(name, "live"); pubStream.publish(name, "record"); }

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  • ArrayAdapter need to be clear even i am creating a new one

    - by Roi
    Hello I'm having problems understanding how the ArrayAdapter works. My code is working but I dont know how.(http://amy-mac.com/images/2013/code_meme.jpg) I have my activity, inside it i have 2 private classes.: public class MainActivity extends Activity { ... private void SomePrivateMethod(){ autoCompleteTextView.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_spinner_dropdown_item, new ArrayList<String>(Arrays.asList("")))); autoCompleteTextView.addTextChangedListener(new MyTextWatcher()); } ... private class MyTextWatcher implements TextWatcher { ... } private class SearchAddressTask extends AsyncTask<String, Void, String[]> { ... } } Now inside my textwatcher class i call the search address task: @Override public void afterTextChanged(Editable s) { new SearchAddressTask().execute(s.toString()); } So far so good. In my SearchAddressTask I do some stuff on doInBackground() that returns the right array. On the onPostExecute() method i try to just modify the AutoCompleteTextView adapter to add the values from the array obtained in doInBackground() but the adapter cannot be modified: NOT WORKING CODE: protected void onPostExecute(String[] addressArray) { ArrayAdapter<String> adapter = (ArrayAdapter<String>) autoCompleteDestination.getAdapter(); adapter.clear(); adapter.addAll(new ArrayList<String>(Arrays.asList(addressArray))); adapter.notifyDataSetChanged(); Log.d("SearchAddressTask", "adapter isEmpty : " + adapter.isEmpty()); // Returns true!!??! } I dont get why this is not working. Even if i run it on UI Thread... I kept investigating, if i recreate the arrayAdapter, is working in the UI (Showing the suggestions), but i still need to clear the old adapter: WORKING CODE: protected void onPostExecute(String[] addressArray) { ArrayAdapter<String> adapter = (ArrayAdapter<String>) autoCompleteDestination.getAdapter(); adapter.clear(); autoCompleteDestination.setAdapter(new ArrayAdapter<String>(NewDestinationActivity.this,android.R.layout.simple_spinner_dropdown_item, new ArrayList<String>(Arrays.asList(addressArray)))); //adapter.notifyDataSetChanged(); // no needed Log.d("SearchAddressTask", "adapter isEmpty : " + adapter.isEmpty()); // keeps returning true!!??! } So my question is, what is really happening with this ArrayAdapter? why I cannot modify it in my onPostExecute()? Why is working in the UI if i am recreating the adapter? and why i need to clear the old adapter then? I dont know there are so many questions that I need some help in here!! Thanks!!

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  • not sure if this is my mistake ~~ vs2010 Add Service Reference fails

    - by gerryLowry
    https://tbe.taleo.net/MANAGER/dispatcher/servlet/rpcrouter the above is from Taleo's API guide. I'm trying to create a WCF Client (e.g.: " Creating Your First WCF Client" http://channel9.msdn.com/shows/Endpoint/Endpoint-Screencasts-Creating-Your-First-WCF-Client/ ) The tbe.taleo... link is from Taleo's API documentation. Likely my understanding is flawed. My assumption is that when the link from Taleo is entered into the vs2010 "Add Service Reference" dialog and GO is clicked, then vs2010 should retrieve a proper WSDL/SOAP envelope back from the Taleo link. That does not happen; instead an error occurs. Fiddler2 (http://fiddler2.com) displays the status code 500 "HTTP/1.1 500 Internal Server Error". [FULL DETAILS BELOW] "WcfTestClient.exe" gives a similar error: [WcfTestClient DETAILS BELOW] QUESTION: is it me, or is the Taleo link flawed? Thank you, Gerry [FULL DETAILS "Add Service Reference"] The HTML document does not contain Web service discovery information. Metadata contains a reference that cannot be resolved: 'https://tbe.taleo.net/MANAGER/dispatcher/servlet/rpcrouter'. The content type text/xml;charset=utf-8 of the response message does not match the content type of the binding (application/soap+xml; charset=utf-8). If using a custom encoder, be sure that the IsContentTypeSupported method is implemented properly. The first 544 bytes of the response were: ' SOAP-ENV:Protocol Unsupported content type "application/soap+xml; charset=utf-8", must be: "text/xml". /MANAGER/dispatcher/servlet/rpcrouter '. The remote server returned an error: (500) Internal Server Error. If the service is defined in the current solution, try building the solution and adding the service reference again. [WcfTestClient DETAILS] Error: Cannot obtain Metadata from https://tbe.taleo.net/MANAGER/dispatcher/servlet/rpcrouter If this is a Windows (R) Communication Foundation service to which you have access, please check that you have enabled metadata publishing at the specified address. For help enabling metadata publishing, please refer to the MSDN documentation at http://go.microsoft.com/fwlink/?LinkId=65455.WS-Metadata Exchange Error URI: https://tbe.taleo.net/MANAGER/dispatcher/servlet/rpcrouter Metadata contains a reference that cannot be resolved: 'https://tbe.taleo.net/MANAGER/dispatcher/servlet/rpcrouter'. The content type text/xml;charset=utf-8 of the response message does not match the content type of the binding (application/soap+xml; charset=utf-8). If using a custom encoder, be sure that the IsContentTypeSupported method is implemented properly. The first 544 bytes of the response were: 'SOAP-ENV:ProtocolUnsupported content type "application/soap+xml; charset=utf-8", must be: "text/xml"./MANAGER/dispatcher/servlet/rpcrouter'. The remote server returned an error: (500) Internal Server Error.HTTP GET Error URI: https://tbe.taleo.net/MANAGER/dispatcher/servlet/rpcrouter The HTML document does not contain Web service discovery information.

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  • Would Apache running on port 8080 prevent dynamically loaded scripts in JavaScript?

    - by editor
    Had a nice PHP/HTML/JS prototype working on my personal Linode, then tried to throw it into a work machine. The page adds a script tag dynamically with some JavaScript. It's a bunch of Google charts that update based on different timeslices. That code looks something like this: // jQuery $.post to send the beginning and end timestamps $.post("channel_functions.php", data_to_post, function(data){ // the data that's returned is the javascript I want to load var script = document.createElement('script'); var head= document.getElementsByTagName('head')[0]; var script= document.createElement('script'); var text = document.createTextNode(data); script.type= 'text/javascript'; script.id = 'chart_data'; script.appendChild(text); // Adding script tag to page head.appendChild(script); // Call the function I know were present in the script tag loadTheCharts(); }); function loadTheCharts() { // These are the functions that were loaded dynamically // By this point the script tag is supposed be loaded, added and eval'd function1(); function2(); } Function1() and function2() don't exist until they get added to the dom, but I don't call loadTheCharts() until after the $.post has run so this doesn't seem to be a problem. I'm one of those dirty PHP coders you mother warned you about, so I'm not well versed in JavaScript beyond what I've read in the typical go-to O'Reilly books. But this code worked fine on my personal dev server, so I'm wondering why it wouldn't work on this new machine. The only difference in setup, from what I can tell, is that the new machine is running on port 8080, so it's 192.168.blah.blah:8080/index.php instead of nicedomain.com/index.php. I see the code was indeed added to the dom when I use webmaster tools to "view generated source" but in Firebug I get an error like "function2() is undefined" even though my understanding was that all script tags are eval'ed when added to . My question: Given what I've laid out, and that the machine is running on :8080, is there a reason anyone can think of as to why a dynamically loaded function like function2() would be defined on the Linode and not on the machine running Apache on 8080?

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  • Linq to SQL Repository ~theory~ - Generic but now uses Linq to Objects?

    - by Matt Tolliday
    The project I am currently working on used Linq to SQL as an ORM data access technology. Its an MVC3 Web app. The problem I faced was primarily due to the inability to mock (for testing) the DataContext which gets autogenerated by the DBML designer. So to solve this issue (after much reading) I refactored the repository system which was in place - single repository with seperate and duplicated access methods for each table which ended up with something like 300 methods only 10 of which were unique - into a single repository with generic methods taking the table and returning more generic types to the upper reaches of the application. My question revolves more around the design I've used to get thus far and the differences I'm noticing in the structure of the app. 1) Having refactored the code from the dark ages which used classic Linq to SQL queries: public Billing GetBilling(int id) { var result = ( from bil in _bicDc.Billings where bil.BillingId == id select bil).SingleOrDefault(); return (result); } it now looks like: public T GetRecordWhere<T>(Expression<Func<T, bool>> predicate) where T : class { T result; try { result = _dataContext.GetTable<T>().Where(predicate).SingleOrDefault(); } catch (Exception ex) { throw ex; } return result; } and is used by the controller with a query along the lines of: _repository.GetRecordWhere<Billing>(x => x.BillingId == 1); which is fine, and precisely what I wanted to achieve. ...however.... I'm also having to do the following to get precisely the result set i require in the controller class (the highest point of the app in essence)... viewModel.RecentRequests = _model.GetAllRecordsWhere<Billing>(x => x.BillingId == 1) .Where(x => x.BillingId == Convert.ToInt32(BillingType.Submitted)) .OrderByDescending(x => x.DateCreated). Take(5).ToList(); This - as far as my understanding is correct - is now using Linq to Objects rather than the Linq to SQL queries I was previously? Is this okay practise? It feels wrong to me but I dont know why. Probably because the logic of the queries is in the very highest tier of the app, rather than the lowest, but... I defer to you good people for advice. One of the issues I considered was bringing the entire table into memory but I understand that using the Iqeryable return type the where clause is taken to the database and evaluated there. Thus returning only the resultset i require... i may be wrong. And if you've made it this far, well done. Thank you, and if you have any advice it is very much appreciated!!

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  • MVC 2 AntiForgeryToken - Why symmetric encryption + IPrinciple?

    - by Brad R
    We recently updated our solution to MVC 2, and this has updated the way that the AntiForgeryToken works. Unfortunately this does not fit with our AJAX framework any more. The problem is that MVC 2 now uses symmetric encryption to encode some properties about the user, including the user's Name property (from IPrincipal). We are able to securely register a new user using AJAX, after which subsequent AJAX calls will be invalid as the anti forgery token will change when the user has been granted a new principal. There are also other cases when this may happen, such as a user updating their name etc. My main question is why does MVC 2 even bother using symmetric encryption? Any then why does it care about the user name property on the principal? If my understanding is correct then any random shared secret will do. The basic principle is that the user will be sent a cookie with some specific data (HttpOnly!). This cookie is then required to match a form variable sent back with each request that may have side effects (POST's usually). Since this is only meant to protect from cross site attacks it is easy to craft up a response that would easily pass the test, but only if you had full access to the cookie. Since a cross site attacker is not going to have access to your user cookies you are protected. By using symmetric encryption, what is the advantage in checking the contents of the cookie? That is, if I already have sent an HttpOnly cookie the attacker cannot override it (unless a browser has a major security issue), so why do I then need to check it again? After having a think about it it appears to be one of those 'added layer of security' cases - but if your first line of defence has fallen (HttpOnly) then the attacker is going to get past the second layer anyway as they have full access to the users cookie collection, and could just impersonate them directly, instead of using an indirect XSS/CSRF attack. Of course I could be missing a major issue, but I haven't found it yet. If there are some obvious or subtle issues at play here then I would like to be aware of them.

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  • IE and Content-disposition inline vs. extension-token

    - by pinkgothic
    Preamble So IE does Mime-Type sniffing. That part's old news. Suggestions of how to combat it tend to be along the lines of 'supply a content-type IE trusts' (i.e. anything that isn't text/plain or application/octet-stream) or 'add extraneous data at the start of the file that is definitely of the type you're serving'. Now, I'm working on an application that has to allow message attachments (like in e-mails), and we want to close up XSS vectors. IE's mime sniffing is one of those vectors - a text/plain file with html content will trigger as html. Recoding isn't an option at this point, changing the attachments the user has provided can only happen if there is absolutely no doubt about the maliciousness of the file - and someone might want to send HTML as text. Now, Microsoft's MSDN article implies the situation might be easier to fix than advertised: If Internet Explorer knows the Content-Type specified and there is no Content-Disposition data, Internet Explorer performs a "MIME sniff," [...] Great! Except I don't have IE nor current means to reliably install it (I realise this is a fairly sad state for a webdeveloper to be in, I hope to fix this soon) and this is grey theory that I can't quite seem to get confirmed one way or the other. Local sources say that line is hogwash - IE will mime sniff anything that is Content-Disposition: inline / <default> and not specific enough for its tastes in -Type. But what about x-* ('extension-token' in the RFC)? Trying to google for how browsers handle Content-Disposition: <extension-token> hasn't yielded anything (though I may just be doing it wrong, my understanding of Google is seriously slipping lately). I found one question that looked promising, but turned out to be a misunderstanding on side of the thread author, meaning that the train of thought was never actually addressed there. Question(s) Does IE really Mime sniff if you expressly pass Content-Disposition: inline? If so: Does anyone here know how browsers handle Content-Disposition: <extension-token>? If they do this in a way that is for my purposes benign, by presuming it to be synonymous with the default (effectively 'inline', though I hear it's not defined anywhere?), is it specific enough for IE not to Mime sniff? Or am I actually shooting myself in the foot by thinking of pursuing this avenue?

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  • MSBuild: Items + Batching + CreateItem + Transforms Question

    - by KeithCS
    I have this bit of an msbuild project that is making me wonder why it the outcome is the way it is. Not that it is causing an issue or anything of the sort, but I would like to try and better my understanding of it. <?xml version="1.0" encoding="utf-8" ?> <Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003" DefaultTargets="TestTarget1;TestTarget2" ToolsVersion="3.5"> <ItemGroup> <PathDir Include="C:\RootDir\UniqueDir1"/> <PathDir Include="C:\RootDir\UniqueDir2" /> </ItemGroup> <Target Name="TestTarget1" Outputs="%(PathDir.Identity)"> <PropertyGroup> <RootPath>%(PathDir.Identity)</RootPath> </PropertyGroup> <ItemGroup> <SubDirectory Include="Common1"/> <SubDirectory Include="Common2"/> </ItemGroup> <CreateItem Include="@(SubDirectory->'$(RootPath)\%(Identity)')"> <Output TaskParameter="Include" ItemName="FullPath"/> </CreateItem> <Message Text="@(FullPath)"/> </Target> <Target Name="TestTarget2"> <Message Text="@(FullPath)"/> </Target> </Project> So I have two main paths that are unique, and within each I have two directories with the same names in each of the unique paths. In target1, I am batching against the identity of the items in PathDir, and then performing a transform on item SubDirectory, which contains the common folder names found in the unique directories, to create a new item containing the full paths. So anyways, after that, the output for the targets is as follows: Target 1: C:\RootDir\UniqueDir1\Common1;C:\RootDir\UniqueDir1\Common2 C:\RootDir\UniqueDir2\Common1;C:\RootDir\UniqueDir2\Common2 Target 2: C:\RootDir\UniqueDir1\Common1;C:\RootDir\UniqueDir1\Common2;C:\RootDir\UniqueDir2\Common1;C:\RootDir\UniqueDir2\Common2 So my question I guess is ... why does target1 only display the directories containing the directory it is batching against? I know it probably has to do with batching, but thats all I know.

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  • XML Return from an Oracle Stored Procedure

    - by Tequila Jinx
    Unfortunately most of my DB experience has been with MSSQL which tends to hold your hand a lot more than Oracle. What I'm trying to do is fairly trivial in tSQL, however, pl/sql is giving me a headache. I have the following procedure: CREATE OR REPLACE PROCEDURE USPX_GetUserbyID (USERID USERS.USERID%TYPE, USERRECORD OUT XMLTYPE) AS BEGIN SELECT XMLELEMENT("user" , XMLATTRIBUTES(u.USERID AS "userid", u.companyid as "companyid", u.usertype as "usertype", u.status as "status", u.personid as "personid") , XMLFOREST( p.FIRSTNAME AS "firstname" , p.LASTNAME AS "lastname" , p.EMAIL AS "email" , p.PHONE AS "phone" , p.PHONEEXTENSION AS "extension") , XMLELEMENT("roles", (SELECT XMLAGG(XMLELEMENT("role", r.ROLETYPE)) FROM USER_ROLES r WHERE r.USERID = USERID AND r.ISACTIVE = 1 ) ) , XMLELEMENT("watches", (SELECT XMLAGG( XMLELEMENT("watch", XMLATTRIBUTES(w.WATCHID AS "id", w.TICKETID AS "ticket") ) ) FROM USER_WATCHES w WHERE w.USERID = USERID AND w.ISACTIVE = 1 ) ) ) AS "RESULT" INTO USERRECORD FROM USERS u LEFT JOIN PEOPLE p ON p.PERSONID = u.PERSONID WHERE u.USERID = USERID; END USPX_GetUserbyID; When executed, it should return an XML document with the following structure: <user userid="" companyid="" usertype="" status="" personid=""> <firstname /> <lastname /> <email /> <phone /> <extension /> <roles> <role /> </roles> <watches> <watch id="" ticket="" /> </watches> </user> When I execute the query itself, replacing the USERID parameter with a string and removing the "into" clause, the query runs fine and returns the expected structure. However, when the procedure attempts to execute the query, passing the results of the XMLELEMENT function into the USERRECORD output parameter, I get the following exception: Error report: ORA-01422: exact fetch returns more than requested number of rows ORA-06512: at "USPX_GETUSERBYID", line 4 ORA-06512: at line 3 01422. 00000 - "exact fetch returns more than requested number of rows" *Cause: The number specified in exact fetch is less than the rows returned. *Action: Rewrite the query or change number of rows requested I'm baffled trying to nail this down, and unfortunately my google-fu hasn't helped. I've found plenty of Oracle SQL|XML examples, but none that deal with XML returns from a procedure. Note: I know that an alternate method of retrieving XML using DBMS methods exists, however, it's my understanding that that functionality is deprecated in favor of SQL|XML.

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  • PyOpenGL - passing transformation matrix into shader

    - by M-V
    I am having trouble passing projection and modelview matrices into the GLSL shader from my PyOpenGL code. My understanding is that OpenGL matrices are column major, but when I pass in projection and modelview matrices as shown, I don't see anything. I tried the transpose of the matrices, and it worked for the modelview matrix, but the projection matrix doesn't work either way. Here is the code: import OpenGL from OpenGL.GL import * from OpenGL.GL.shaders import * from OpenGL.GLU import * from OpenGL.GLUT import * from OpenGL.GLUT.freeglut import * from OpenGL.arrays import vbo import numpy, math, sys strVS = """ attribute vec3 aVert; uniform mat4 uMVMatrix; uniform mat4 uPMatrix; uniform vec4 uColor; varying vec4 vCol; void main() { // option #1 - fails gl_Position = uPMatrix * uMVMatrix * vec4(aVert, 1.0); // option #2 - works gl_Position = vec4(aVert, 1.0); // set color vCol = vec4(uColor.rgb, 1.0); } """ strFS = """ varying vec4 vCol; void main() { // use vertex color gl_FragColor = vCol; } """ # particle system class class Scene: # initialization def __init__(self): # create shader self.program = compileProgram(compileShader(strVS, GL_VERTEX_SHADER), compileShader(strFS, GL_FRAGMENT_SHADER)) glUseProgram(self.program) self.pMatrixUniform = glGetUniformLocation(self.program, 'uPMatrix') self.mvMatrixUniform = glGetUniformLocation(self.program, "uMVMatrix") self.colorU = glGetUniformLocation(self.program, "uColor") # attributes self.vertIndex = glGetAttribLocation(self.program, "aVert") # color self.col0 = [1.0, 1.0, 0.0, 1.0] # define quad vertices s = 0.2 quadV = [ -s, s, 0.0, -s, -s, 0.0, s, s, 0.0, s, s, 0.0, -s, -s, 0.0, s, -s, 0.0 ] # vertices self.vertexBuffer = glGenBuffers(1) glBindBuffer(GL_ARRAY_BUFFER, self.vertexBuffer) vertexData = numpy.array(quadV, numpy.float32) glBufferData(GL_ARRAY_BUFFER, 4*len(vertexData), vertexData, GL_STATIC_DRAW) # render def render(self, pMatrix, mvMatrix): # use shader glUseProgram(self.program) # set proj matrix glUniformMatrix4fv(self.pMatrixUniform, 1, GL_FALSE, pMatrix) # set modelview matrix glUniformMatrix4fv(self.mvMatrixUniform, 1, GL_FALSE, mvMatrix) # set color glUniform4fv(self.colorU, 1, self.col0) #enable arrays glEnableVertexAttribArray(self.vertIndex) # set buffers glBindBuffer(GL_ARRAY_BUFFER, self.vertexBuffer) glVertexAttribPointer(self.vertIndex, 3, GL_FLOAT, GL_FALSE, 0, None) # draw glDrawArrays(GL_TRIANGLES, 0, 6) # disable arrays glDisableVertexAttribArray(self.vertIndex) class Renderer: def __init__(self): pass def reshape(self, width, height): self.width = width self.height = height self.aspect = width/float(height) glViewport(0, 0, self.width, self.height) glEnable(GL_DEPTH_TEST) glDisable(GL_CULL_FACE) glClearColor(0.8, 0.8, 0.8,1.0) glutPostRedisplay() def keyPressed(self, *args): sys.exit() def draw(self): glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT) # build projection matrix fov = math.radians(45.0) f = 1.0/math.tan(fov/2.0) zN, zF = (0.1, 100.0) a = self.aspect pMatrix = numpy.array([f/a, 0.0, 0.0, 0.0, 0.0, f, 0.0, 0.0, 0.0, 0.0, (zF+zN)/(zN-zF), -1.0, 0.0, 0.0, 2.0*zF*zN/(zN-zF), 0.0], numpy.float32) # modelview matrix mvMatrix = numpy.array([1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.5, 0.0, -5.0, 1.0], numpy.float32) # render self.scene.render(pMatrix, mvMatrix) # swap buffers glutSwapBuffers() def run(self): glutInitDisplayMode(GLUT_RGBA) glutInitWindowSize(400, 400) self.window = glutCreateWindow("Minimal") glutReshapeFunc(self.reshape) glutDisplayFunc(self.draw) glutKeyboardFunc(self.keyPressed) # Checks for key strokes self.scene = Scene() glutMainLoop() glutInit(sys.argv) prog = Renderer() prog.run() When I use option #2 in the shader without either matrix, I get the following output: What am I doing wrong?

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  • How do you stop a user-instance of Sql Server? (Sql Express user instance database files locked, eve

    - by Bittercoder
    When using SQL Server Express 2005's User Instance feature with a connection string like this: <add name="Default" connectionString="Data Source=.\SQLExpress; AttachDbFilename=C:\My App\Data\MyApp.mdf; Initial Catalog=MyApp; User Instance=True; MultipleActiveResultSets=true; Trusted_Connection=Yes;" /> We find that we can't copy the database files MyApp.mdf and MyApp_Log.ldf (because they're locked) even after stopping the SqlExpress service, and have to resort to setting the SqlExpress service from automatic to manual startup mode, and then restarting the machine, before we can then copy the files. It was my understanding that stopping the SqlExpress service should stop all the user instances as well, which should release the locks on those files. But this does not seem to be the case - could anyone shed some light on how to stop a user instance, such that it's database files are no longer locked? Update OK, I stopped being lazy and fired up Process Explorer. Lock was held by sqlserver.exe - but there are two instances of sql server: sqlserver.exe PID: 4680 User Name: DefaultAppPool sqlserver.exe PID: 4644 User Name: NETWORK SERVICE The file is open by the sqlserver.exe instance with the PID: 4680 Stopping the "SQL Server (SQLEXPRESS)" service, killed off the process with PID: 4644, but left PID: 4680 alone. Seeing as the owner of the remaining process was DefaultAppPool, next thing I tried was stopping IIS (this database is being used from an ASP.Net application). Unfortunately this didn't kill the process off either. Manually killing off the remaining sql server process does remove the open file handle on the database files, allowing them to be copied/moved. Unfortunately I wish to copy/restore those files in some pre/post install tasks of a WiX installer - as such I was hoping there might be a way to achieve this by stopping a windows service, rather then having to shell out to kill all instances of sqlserver.exe as that poses some problems: Killing all the sqlserver.exe instances may have undesirable consequencies for users with other Sql Server instances on their machines. I can't restart those instances easily. Introduces additional complexities into the installer. Does anyone have any further thoughts on how to shutdown instances of sql server associated with a specific user instance?

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  • Any tool(s) for knowing the layout (segments) of running process in Windows?

    - by claws
    I've always been curious about How exactly the process looks in memory? What are the different segments(parts) in it? How exactly will be the program (on the disk) & process (in the memory) are related? My previous question: http://stackoverflow.com/questions/1966920/more-info-on-memory-layout-of-an-executable-program-process In my quest, I finally found a answer. I found this excellent article that cleared most of my queries: http://www.linuxforums.org/articles/understanding-elf-using-readelf-and-objdump_125.html In the above article, author shows how to get different segments of the process (LINUX) & he compares it with its corresponding ELF file. I'm quoting this section here: Courious to see the real layout of process segment? We can use /proc//maps file to reveal it. is the PID of the process we want to observe. Before we move on, we have a small problem here. Our test program runs so fast that it ends before we can even dump the related /proc entry. I use gdb to solve this. You can use another trick such as inserting sleep() before it calls return(). In a console (or a terminal emulator such as xterm) do: $ gdb test (gdb) b main Breakpoint 1 at 0x8048376 (gdb) r Breakpoint 1, 0x08048376 in main () Hold right here, open another console and find out the PID of program "test". If you want the quick way, type: $ cat /proc/`pgrep test`/maps You will see an output like below (you might get different output): [1] 0039d000-003b2000 r-xp 00000000 16:41 1080084 /lib/ld-2.3.3.so [2] 003b2000-003b3000 r--p 00014000 16:41 1080084 /lib/ld-2.3.3.so [3] 003b3000-003b4000 rw-p 00015000 16:41 1080084 /lib/ld-2.3.3.so [4] 003b6000-004cb000 r-xp 00000000 16:41 1080085 /lib/tls/libc-2.3.3.so [5] 004cb000-004cd000 r--p 00115000 16:41 1080085 /lib/tls/libc-2.3.3.so [6] 004cd000-004cf000 rw-p 00117000 16:41 1080085 /lib/tls/libc-2.3.3.so [7] 004cf000-004d1000 rw-p 004cf000 00:00 0 [8] 08048000-08049000 r-xp 00000000 16:06 66970 /tmp/test [9] 08049000-0804a000 rw-p 00000000 16:06 66970 /tmp/test [10] b7fec000-b7fed000 rw-p b7fec000 00:00 0 [11] bffeb000-c0000000 rw-p bffeb000 00:00 0 [12] ffffe000-fffff000 ---p 00000000 00:00 0 Note: I add number on each line as reference. Back to gdb, type: (gdb) q So, in total, we see 12 segment (also known as Virtual Memory Area--VMA). But I want to know about Windows Process & PE file format. Any tool(s) for getting the layout (segments) of running process in Windows? Any other good resources for learning more on this subject? EDIT: Are there any good articles which shows the mapping between PE file sections & VA segments?

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  • I am wondering how the Plural-Field generic is to be rendered in the REST OpenSocial 1.0 API specifi

    - by DaveGrahamOrg
    In the OpenSocial Data specificaiton 1.0 for a Person object (social profile data) it includes the use of a generic called Plural-Field. The spec can be found at: http://opensocial-resources.googlecode.com/svn/spec/1.0/Social-Data.xml#Person In the 1.0 data specification there is no XSD and no examples showing the use of this generic Plural-Field. After puzzeling the spec for some time I think I might understand the user of this generic. I was hoping that someone could confirm or correct my understanding. For example the accounts field is a generic Plural-Field<Account> while the activities field is Plural-Field <string>. Am I right in assuming that the result XML would look like: <accounts> <Plural-Field> <primary>true</primary> <type>ntlm</type> <value> <Account> <domain>MYDOMAIN</domain> <userid>MYDOMAIN\davegraham</userid> <username>davegraham</username> </Account> </value> </Plural-Field> <Plural-Field> <primary>false</primary> <type>claims</type> <value> <Account> <domain>i:0#.f|claimsDomain</domain> <userid>i:0#.f|claimsDomain|davegraham</userid> <username>davegraham</username> </Account> </value> </Plural-Field> </accounts> <activities> <Plural-Field> <primary>true</primary> <type>ntlm</type> <value>cycling</value> </Plural-Field> <Plural-Field> <primary>false</primary> <type>claims</type> <value>swiming</value> </Plural-Field> </activities> Am I right in my interpretation of the spec?

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  • Mercurial for Beginners: The Definitive Practical Guide

    - by Laz
    Inspired by Git for beginners: The definitive practical guide. This is a compilation of information on using Mercurial for beginners for practical use. Beginner - a programmer who has touched source control without understanding it very well. Practical - covering situations that the majority of users often encounter - creating a repository, branching, merging, pulling/pushing from/to a remote repository, etc. Notes: Explain how to get something done rather than how something is implemented. Deal with one question per answer. Answer clearly and as concisely as possible. Edit/extend an existing answer rather than create a new answer on the same topic. Please provide a link to the the Mercurial wiki or the HG Book for people who want to learn more. Questions: Installation/Setup How to install Mercurial? How to set up Mercurial? How do you create a new project/repository? How do you configure it to ignore files? Working with the code How do you get the latest code? How do you check out code? How do you commit changes? How do you see what's uncommitted, or the status of your current codebase? How do you destroy unwanted commits? How do you compare two revisions of a file, or your current file and a previous revision? How do you see the history of revisions to a file? How do you handle binary files (visio docs, for instance, or compiler environments)? How do you merge files changed at the "same time"? Tagging, branching, releases, baselines How do you 'mark' 'tag' or 'release' a particular set of revisions for a particular set of files so you can always pull that one later? How do you pull a particular 'release'? How do you branch? How do you merge branches? How do you merge parts of one branch into another branch? Other Good GUI/IDE plugin for Mercurial? Advantages/disadvantages? Any other common tasks a beginner should know? How do I interface with Subversion? Other Mercurial references Mercurial: The Definitive Guide Mercurial Wiki Meet Mercurial | Peepcode Screencast

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  • More GCC link time issues: undefined reference to main

    - by vikramtheone
    Hi Guys, I'm writing software for a Cortex-A8 processor and I have to write some ARM assembly code to access specific registers. I'm making use of the gnu compilers and related tool chains, these tools are installed on the processor board(Freescale i.MX515) with Ubuntu. I make a connection to it from my host PC(Windows) using WinSCP and the PuTTY terminal. As usual I started with a simple C project having main.c and functions.s. I compile the main.c using GCC, assemble the functions.s using as and link the generated object files using once again GCC, but I get strange errors during this process. An important finding - Meanwhile, I found out that my assembly code may have some issues because when I individually assemble it using the command as -o functions.o functions.s and try running the generated functions.o using ./functions.o command, the bash shell is failing to recognize this file as an executable(on pressing tab functions.o is not getting selected/PuTTY is not highlighting the file). Can anyone suggest whats happening here? Are there any specific options I have to send, to GCC during the linking process? The errors I see are strange and beyond my understanding, I don't understand to what the GCC is referring. I'm pasting here the contents of main.c, functions.s, the Makefile and the list of errors. Help, please!!! Vikram main.c #include <stdio.h> #include <stdlib.h> int main(void) { puts("!!!Hello World!!!"); /* prints !!!Hello World!!! */ return EXIT_SUCCESS; } functions.s * Main program */ .equ STACK_TOP, 0x20000800 .text .global _start .syntax unified _start: .word STACK_TOP, start .type start, function start: movs r0, #10 movs r1, #0 .end Makefile all: hello hello: main.o functions.o gcc -o main.o functions.o main.o: main.c gcc -c -mcpu=cortex-a8 main.c functions.o: functions.s as -mcpu=cortex-a8 -o functions.o functions.s Errors ubuntu@ubuntu-desktop:~/Documents/Project/Others/helloworld$ make gcc -c -mcpu=cortex-a8 main.c as -mcpu=cortex-a8 -o functions.o functions.s gcc -o main.o functions.o functions.o: In function `_start': (.text+0x0): multiple definition of `_start' /usr/lib/gcc/arm-linux-gnueabi/4.3.3/../../../crt1.o:init.c:(.text+0x0): first defined here /usr/lib/gcc/arm-linux-gnueabi/4.3.3/../../../crt1.o: In function `_start': init.c:(.text+0x30): undefined reference to `main' collect2: ld returned 1 exit status make: *** [hello] Error 1

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  • Searches (and general querying) with HBase and/or Cassandra (best practices?)

    - by alexeypro
    I have User model object with quite few fields (properties, if you wish) in it. Say "firstname", "lastname", "city" and "year-of-birth". Each user also gets "unique id". I want to be able to search by them. How do I do that properly? How to do that at all? My understanding (will work for pretty much any key-value storage -- first goes key, then value) u:123456789 = serialized_json_object ("u" as a simple prefix for user's keys, 123456789 is "unique id"). Now, thinking that I want to be able to search by firstname and lastname, I can save in: f:Steve = u:384734807,u:2398248764,u:23276263 f:Alex = u:12324355,u:121324334 so key is "f" - which is prefix for firstnames, and "Steve" is actual firstname. For "u:Steve" we save as value all user id's who are "Steve's". That makes every search very-very easy. Querying by few fields (properties) -- say by firstname (i.e. "Steve") and lastname (i.e. "l:Anything") is still easy - first get list of user ids from "f:Steve", then list from "l:Anything", find crossing user ids, an here you go. Problems (and there are quite a few): Saving, updating, deleting user is a pain. It has to be atomic and consistent operation. Also, if we have size of value limited to some value - then we are in (potential) trouble. And really not of an answer here. Only zipping the list of user ids? Not too cool, though. What id we want to add new field to search by. Eventually. Say by "city". We certainly can do the same way "c:Los Angeles" = ..., "c:Chicago" = ..., but if we didn't foresee all those "search choices" from the very beginning, then we will have to be able to create some night job or something to go by all existing User records and update those "c:CITY" for them... Quite a big job! Problems with locking. User "u:123" updates his name "Alex", and user "u:456" updates his name "Alex". They both have to update "f:Alex" with their id's. That means either we get into overwriting problem, or one update will wait for another (and imaging if there are many of them?!). What's the best way of doing that? Keeping in mind that I want to search by many fields? P.S. Please, the question is about HBase/Cassandra/NoSQL/Key-Value storages. Please please - no advices to use MySQL and "read about" SELECTs; and worry about scaling problems "later". There is a reason why I asked MY question exactly the way I did. :-)

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  • .htaccess mod_rewrite issue

    - by Orhan Toy
    Almost in any project I work on, some issues with .htaccess occur. I usually just find the easiest solution and leave it because I don't have any knowledge or understanding for Apache, servers etc. But this time I thought I would ask you guys. This is the files and folders in my (simplified) setup: /modrewrite-test .htaccess /config /inc /lib /public_html .htaccess /cms /navigation index.php edit.php /pages index.php edit.php login.php page.php The "config", "inc" and "lib" folders are meant to be "hidden" from the root of the website. I try to accomplish this by making a .htaccess-file in the root that redirects the user to "public_html". The .htacess-file contains this: RewriteEngine On RewriteRule (.*) public_html/$1 This works perfect. If I type "http://localhost/modrewrite-test/login.php" in my browser, I end up in public_html/login.php which is my intention. So this works fine. The .htaccess-file in "public_html" contains this: RewriteEngine On # Root RewriteRule ^$ page.php [L] # Login RewriteRule ^(admin)|(login)\/?$ login.php [L] # Page (if not a file/directory) RewriteCond %{REQUEST_FILENAME} !-d RewriteCond %{REQUEST_FILENAME} !-f RewriteRule ^(.*)$ page.php?url=$1 [L] The first rewrite just redirects me to public_html/page.php if I try to reach "http://localhost/modrewrite-test/". The next rewrite is just for the convenience of users trying to log in - so if they try to reach "http://localhost/modrewrite-test/admin" or "http://localhost/modrewrite-test/login" they will end up at the login.php-file. The third and last rewrite handles the rest of the requests. If I try to reach "http://localhost/modrewrite-test/bla/bla/bla" it will just redirect me to public_html/page.php (with the 'url' GET-variable set) instead of finding a folder called "la", containing a folder named "bla" and etc. All of these things work perfect but a minor issues occurs when I for instance try to reach "http://localhost/modrewrite-test/cms/navigation" without a slash at the end of the URL. When I try to reach that page the browser is somehow redirected to "http://localhost/modrewrite-test/public_html/cms/navigation/". The correct page is shown but why does it get redirected and add the "public_html" part in the URL? The desired behavior is that the URL stays intact and that the page public_html/cms/navigation/index.php is shown. The files and folders in the (simplified) can be found at http://highbars.com/modrewrite-test.zip

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  • What are the basics of dealing with user input events in Android?

    - by user279112
    Hello. I thought I had understood this question, but something is quite wrong here. When the user (me, so far) tries to press keys, nothing really happens, and I am having a lot of trouble understanding what it is that I've missed. Consider this before I present some code to help clarify my problem: I am using Android's Lunar Lander example to make my first "real" Android program. In that example, of course, there exist a class LunarView, and class nested therein LunarThread. In my code the equivalents of these classes are Graphics and GraphicsThread, respectively. Also I can make sprite animations in 2D just fine on Android. I have a Player class, and let's say GraphicsThread has a Player member referred to as "player". This class has four coordinates - x1, y1, x2, and y2 - and they define a rectangle in which the sprite is to be drawn. I've worked it out so that I can handle that perfectly. Whenever the doDraw(Canvas canvas) method is invoked, it'll just look at the values of those coordinates and draw the sprite accordingly. Now let's say - and this isn't really what I'm trying to do with the program - I'm trying to make the program where all it does is display the Player sprite at one location of the screen UNTIL the FIRST time the user presses the Dpad's left button. Then the location will be changed to another set position on the screen, and the sprite will be drawn at that position for the rest of the program invariably. Also note that the GraphicsThread member in Graphics is called "thread", and that the SurfaceHolder member in GraphicsThread is called "mSurfaceHolder". So consider this method in class Graphics: @Override public boolean onKeyDown(int keyCode, KeyEvent msg) { return thread.keyDownHandler(keyCode, msg); } Also please consider this method in class GraphicsThread: boolean keyDownHandler(int keyCode, KeyEvent msg) { synchronized (mSurfaceHolder) { if (keyCode == KeyEvent.KEYCODE_DPAD_LEFT) { player.x1 = 100; player.y1 = 100; player.x2 = 120; player.y2 = 150; } } return true; } Now then assuming that player's coordinates start off as (200, 200, 220, 250), why won't he do anything different when I press Dpad: Left? Thanks!

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  • Why is it still so hard to write software?

    - by nornagon
    Writing software, I find, is composed of two parts: the Idea, and the Implementation. The Idea is about thinking: "I have this problem; how do I solve it?" and further, "how do I solve it elegantly?" The answers to these questions are obtainable by thinking about algorithms and architecture. The ideas come partially through analysis and partially through insight and intuition. The Idea is usually the easy part. You talk to your friends and co-workers and you nut it out in a meeting or over coffee. It takes an hour or two, plus revisions as you implement and find new problems. The Implementation phase of software development is so difficult that we joke about it. "Oh," we say, "the rest is a Simple Matter of Code." Because it should be simple, but it never is. We used to write our code on punch cards, and that was hard: mistakes were very difficult to spot, so we had to spend extra effort making sure every line was perfect. Then we had serial terminals: we could see all our code at once, search through it, organise it hierarchically and create things abstracted from raw machine code. First we had assemblers, one level up from machine code. Mnemonics freed us from remembering the machine code. Then we had compilers, which freed us from remembering the instructions. We had virtual machines, which let us step away from machine-specific details. And now we have advanced tools like Eclipse and Xcode that perform analysis on our code to help us write code faster and avoid common pitfalls. But writing code is still hard. Writing code is about understanding large, complex systems, and tools we have today simply don't go very far to help us with that. When I click "find all references" in Eclipse, I get a list of them at the bottom of the window. I click on one, and I'm torn away from what I was looking at, forced to context switch. Java architecture is usually several levels deep, so I have to switch and switch and switch until I find what I'm really looking for -- by which time I've forgotten where I came from. And I do that all day until I've understood a system. It's taxing mentally, and Eclipse doesn't do much that couldn't be done in 1985 with grep, except eat hundreds of megs of RAM. Writing code has barely changed since we were staring at amber on black. We have the theoretical groundwork for much more advanced tools, tools that actually work to help us comprehend and extend the complex systems we work with every day. So why is writing code still so hard?

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  • multiple definition of inline function

    - by K71993
    Hi, I have gone through some posts related to this topic but was not able to sort out my doubt completly. This might be a very navie question. Code Description I have a header file "inline.h" and two translation unit "main.cpp" and "tran.cpp". Details of code are as below inline.h file details #ifndef __HEADER__ #include <stdio.h> extern inline int func1(void) { return 5; } static inline int func2(void) { return 6; } inline int func3(void) { return 7; } #endif main.c file details are below #define <stdio.h> #include <inline.h> int main(int argc, char *argv[]) { printf("%d\n",func1()); printf("%d\n",func2()); printf("%d\n",func3()); return 0; } tran.cpp file details (Not that the functions are not inline here) #include <stdio.h> int func1(void) { return 500; } int func2(void) { return 600; } int func3(void) { return 700; } Question The above code does not compile in gcc compiler whereas compiles in g++ (Assuming you make changes related to gcc in code like changing the code to .c not using any C++ header files... etc). The error displayed is "duplicate definition of inline function - func3". Can you clarify why this difference is present across compile? When you run the program (g++ compiled) by creating two seperate compilation unit (main.o and tran.o and create an executable a.out), the output obtained is 500 6 700 Why does the compiler pick up the definition of the function which is not inline. Actually since #include is used to "add" the inline definiton I had expected 5,6,7 as the output. My understanding was during compilation since the inline definition is found, the function call would be "replaced" by inline function definition. Can you please tell me in detailed steps the process of compilation and linking which would lead us to 500,6,700 output. I can only understand the output 6. Thanks in advance for valuable input.

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  • Why does SFINAE not apply to this?

    - by Simon Buchan
    I'm writing some simple point code while trying out Visual Studio 10 (Beta 2), and I've hit this code where I would expect SFINAE to kick in, but it seems not to: template<typename T> struct point { T x, y; point(T x, T y) : x(x), y(y) {} }; template<typename T, typename U> struct op_div { typedef decltype(T() / U()) type; }; template<typename T, typename U> point<typename op_div<T, U>::type> operator/(point<T> const& l, point<U> const& r) { return point<typename op_div<T, U>::type>(l.x / r.x, l.y / r.y); } template<typename T, typename U> point<typename op_div<T, U>::type> operator/(point<T> const& l, U const& r) { return point<typename op_div<T, U>::type>(l.x / r, l.y / r); } int main() { point<int>(0, 1) / point<float>(2, 3); } This gives error C2512: 'point<T>::point' : no appropriate default constructor available Given that it is a beta, I did a quick sanity check with the online comeau compiler, and it agrees with an identical error, so it seems this behavior is correct, but I can't see why. In this case some workarounds are to simply inline the decltype(T() / U()), to give the point class a default constructor, or to use decltype on the full result expression, but I got this error while trying to simplify an error I was getting with a version of op_div that did not require a default constructor*, so I would rather fix my understanding of C++ rather than to just do what works. Thanks! *: the original: template<typename T, typename U> struct op_div { static T t(); static U u(); typedef decltype(t() / u()) type; }; Which gives error C2784: 'point<op_div<T,U>::type> operator /(const point<T> &,const U &)' : could not deduce template argument for 'const point<T> &' from 'int', and also for the point<T> / point<U> overload.

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  • DriverManager always returns my custom driver regardless of the connection URL

    - by JGB146
    I am writing a driver to act as a wrapper around two separate MySQL connections (to distributed databases). Basically, the goal is to enable interaction with my driver for all applications instead of requiring the application to sort out which database holds the desired data. Most of the code for this is in place, but I'm having a problem in that when I attempt to create connections via the MySQL Driver, the DriverManager is returning an instance of my driver instead of the MySQL Driver. I'd appreciate any tips on what could be causing this and what could be done to fix it! Below is a few relevant snippets of code. I can provide more, but there's a lot, so I'd need to know what else you want to see. First, from MyDriver.java: public MyDriver() throws SQLException { DriverManager.registerDriver(this); } public Connection connect(String url, Properties info) throws SQLException { try { return new MyConnection(info); } catch (Exception e) { return null; } } public boolean acceptsURL(String url) throws SQLException { if (url.contains("jdbc:jgb://")) { return true; } return false; } It is my understanding that this acceptsURL function will dictate whether or not the DriverManager deems my driver a suitable fit for a given URL. Hence it should only be passing connections from my driver if the URL contains "jdbc:jgb://" right? Here's code from MyConnection.java: Connection c1 = null; Connection c2 = null; /** *Constructors */ public DDBSConnection (Properties info) throws SQLException, Exception { info.list(System.out); //included for testing Class.forName("com.mysql.jdbc.Driver").newInstance(); String url1 = "jdbc:mysql://server1.com/jgb"; String url2 = "jdbc:mysql://server2.com/jgb"; this.c1 = DriverManager.getConnection( url1, info.getProperty("username"), info.getProperty("password")); this.c2 = DriverManager.getConnection( url2, info.getProperty("username"), info.getProperty("password")); } And this tells me two things. First, the info.list() call confirms that the correct user and password are being sent. Second, because we enter an infinite loop, we see that the DriverManager is providing new instances of my connection as matches for the mysql URLs instead of the desired mysql driver/connection. FWIW, I have separately tested implementations that go straight to the mysql driver using this exact syntax (al beit only one at a time), and was able to successfully interact with each database individually from a test application outside of my driver.

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  • How to retain the state of a activity that has a GLSurfaceView

    - by user348639
    My problem is our game can switch into menu and setting mode instantly but it will need 4-6 seconds to load texture, init GL render mode eventually I just used 6 simple textures to create 6 sprites in game. Please help me answer two questions: 1. How can I preload our assets in android os to start our game quicker? 2. In order to use a trick to create instance switch between activity, how can I retain my activity with GLSurfaceView state? I order to help you understanding my situation, please read the following code: The game using 3 activities as you can see in following configuration: <application android:label="@string/app_name" android:icon="@drawable/icon" android:allowBackup="true"> <activity android:name=".Menu" android:screenOrientation="portrait" android:theme="@android:style/Theme.NoTitleBar.Fullscreen" android:launchMode="singleTop"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <activity android:name=".ReTouch" android:screenOrientation="portrait" /> <activity android:name=".Preference" android:screenOrientation="portrait" android:theme="@android:style/Theme.NoTitleBar.Fullscreen" /> </application> My .ReTouch class is a class that extended from RokonActivity (I am using rokon engine for my game), this engine will create a GLSurefaceView to render my game in OpenGL ES You can get RokonAcitivity's source code here: http://code.google.com/p/rokon/source/browse/tags/release/1.1.1/src/com/stickycoding/Rokon/RokonActivity.java public class ReTouch extends RokonActivity { public static final int REPLAY_DELAY_INTERVAL = 1000; private ReTouchGameBoard reTouchGame; and .Menu, .Preference are two normal standard activity in an android application. I am using this method to start and switch between activities: playButton.setOnClickListener(new OnClickListener() { public void onClick(View v) { soundPool.play(soundId, 1, 1, 1, 0, 1); startActivity(new Intent(Menu.this, ReTouch.class)); } }); settingButton.setOnClickListener(new OnClickListener() { public void onClick(View v) { soundPool.play(soundId, 1, 1, 1, 0, 1); startActivity(new Intent(Menu.this, Preference.class)); } }); quitButton.setOnClickListener(new OnClickListener() { public void onClick(View v) { soundPool.play(soundId, 1, 1, 1, 0, 1); finish(); } });

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