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  • trying to validate user input in php

    - by user225269
    I'm trying to validate user input in php. This code will check if the values are null or not. If it is null, this will require the user to input the values that are null. When all the text boxes in the html form that came before this. This code will show the submit button, and that submit button will save the inputted data into the mysql database. But the problem is that the value that is saved is zero zero and zero, what might be the cause of this? <html> <head> <title>Admission Information Sheet</title> <meta http-equiv="Content-Type" content="text/html; Western (ISO-8859-1)"> <meta name="author" content=" "> <title> <style> input { font-size: 16px;} </style> <?php include('header.php'); ?> <div id="main_content"> </div> <?php include('footer.php'); ?> <table border="1" width="900" border="0" align="left" cellpadding="0" cellspacing="1" bgcolor="#CCCCCC"> <tr> <form name="form1.1" method="POST" action="aisaction.php"> <?php $NURSE = $_POST[nurse]; $TELNUM = $_POST[telnum]; $HOSPNUM = $_POST[hnum]; $ROOMNUM = $_POST[rnum]; $LASTNAME = $_POST[lname]; $FIRSTNAME = $_POST[fname]; $MIDNAME = $_POST[mname]; $AD = $_POST[ad]; $ADATE = $_POST[adate]; $ADTIME = $_POST[adtime]; $CSTAT = $_POST[cs]; $AGE = $_POST[age]; $BDAY = $_POST[bday]; $SEX = $_POST[sex]; ?> <td> <table width="100%" border="0" cellpadding="2" cellspacing="1" bgcolor="#FFFFFF"> <tr> <td colspan="12" style="background:#9ACD32; color:white; border:white 1px solid; text-align: center"><strong><font size="3">ADMISSION INFORMATION SHEET</strong></td> </tr> <tr> </td><br> <td width="54"><font size="3">Hospital #</td> <td width="3">:</td> <td width="168"><input type="display" name="hnum" disabled="true" value= "<?php print "$HOSPNUM";?>"><br> <font color="red"> <?php if(empty($HOSPNUM)) print "* Hospital Number required!<br>"; ?> </td> <td width="41"><font size="3">Room #</td> <td width="3">:</td> <td width="168"><input type="display" name="rnum" disabled="true" value= "<?php print "$ROOMNUM";?>"><br> <font color="red"> <?php if(empty($ROOMNUM)) print "* Room Number required!<br>"; ?> </td> <td width="67"><font size="3">Admission Date</td> <td width="3">:</td> <td width="168"><input type="display" name="adate" disabled="true" value= "<?php print "$ADATE";?>"><br> <font color="red"> <?php if(empty($ADATE)) print "* Admission Date required!<br>"; ?> </td> </tr> <tr> <td><font size="3">Last Name</td> <td>:</td> <td><input type="display" name="lname" disabled="true" value= "<?php print "$LASTNAME";?>"><br> <font color="red"> <?php if(empty($LASTNAME)) print "* Last Name required!<br>"; ?> </td> <td><font size="3">First Name</td> <td>:</td> <td><input type="display" name="fname" disabled="true" value= "<?php print "$FIRSTNAME";?>"><br> <font color="red"> <?php if(empty($FIRSTNAME)) print "* First Name required!<br>"; ?> </td> <td><font size="3">Middle Name</td> <td>:</td> <td><input type="display" name="mname" disabled="true" value= "<?php print "$MIDNAME";?>"><br> <font color="red"> <?php if(empty($MIDNAME)) print "* Middle Name required!<br>"; ?> </td> <td><font size="3">Admit time</td> <td>:</td> <td><input type="display" name="mname" disabled="true" value= "<?php print "$ADTIME";?>"><br> <font color="red"> <?php if(empty($ADTIME)) print "* Adtime required!<br>"; ?> </td> </tr> <tr> <td><font size="3">Civil Status</td> <td>:</td> <td><input type="display" name="cs" disabled="true" value= "<?php print "$CSTAT";?>"><br> <font color="red"> <?php if(empty($CSTAT)) print "* Civil Status required!<br>"; ?> </td> <td><font size="3">Age</td> <td>:</td> <td><input type="display" name="age" disabled="true" value= "<?php print "$AGE";?>"><br> <font color="red"> <?php if(empty($AGE)) print "* Age required!<br>"; ?> </td> <td><font size="3">Birthday</td> <td>:</td> <td><input type="display" name="bday" disabled="true" value= "<?php print "$BDAY";?>"><br> <font color="red"> <?php if(empty($BDAY)) print "* Birthday required!<br>"; ?> </td> </tr> <tr> <td><font size="3">Address</td> <td>:</td> <td><input type="display" name="address" disabled="true" value= "<?php print "$AD";?>"><br> <font color="red"> <?php if(empty($AD)) print "* Address required!<br>"; ?> </td> <td><font size="3">Telephone #</td> <td>:</td> <td><input type="display" name="telnum" disabled="true" value= "<?php print "$TELNUM";?>"></td> <td width="23"><font size="3">Sex</td> <td width="3">:</td> <td width="174"><input type="display" name="sex" disabled="true" value= "<?php print "$SEX";?>"><br> <font color="red"> <?php if(empty($SEX)) print "* Gender required!<br>"; ?> </td> </tr> <tr> <td><font size="3">Pls. Check</td> <td>:</td> <td><input name="stats1" type="checkbox" id="SSS" value="SSS">SSS</td> <td><font size="3"></td> <td>:</td> <td><input name="stats1" type="checkbox" id="nonmed" value="NonMedicare">Non Medicare</td> <td><font size="3"></td> <td>:</td> <td><input name="stats1" type="checkbox" id="sh" value="stockholder">Stockholder</td> </tr> <tr> <td><font size="3"></td> <td></td> <td><input name="stats1" type="checkbox" id="gsis" value="GSIS">GSIS</td> <td><font size="3"></td> <td></td> <td><input name="stats1" type="checkbox" id="senior" value="seniorcitizen">Senior-Citizen</td> <tr> <td><font size="3"></td> <td></td> <td><input name="stats1" type="checkbox" id="dep" value="dependent">Dependent</td> <td><font size="3"></td> <td></td> <td><input name="stats1" type="checkbox" id="emp" value="employee">Employee</td> </tr> <tr> <td><font size="3">Attending Nurse</td> <td>:</td> <td><input type="display" name="nurse" disabled="true" value= "<?php print "$NURSE";?>"><br> <font color="red"> <?php if(empty($NURSE)) print "* Admitting/Attending Nurse required!<br>"; ?> </td> </tr> <tr> <td>&nbsp;</td> <td>&nbsp;</td> <td><input type="button" value="Back" onClick="history.go(-1);return true;"> <?php $val1 = $_POST['NURSE']; if($_POST['NURSE'] !="") { ?> <form action="aisaction.php" method="POST" target="_window"> <input type="hidden" name="submit" value="yes"> <input type="submit" value="submit"> </form> <?php } ?> </td> </td> </tr> </table> </td> </form> </tr> </table> </head> </html>

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  • SQL Authority News – Download Microsoft SQL Server 2014 Feature Pack and Microsoft SQL Server Developer’s Edition

    - by Pinal Dave
    Yesterday I attended the SQL Server Community Launch in Bangalore and presented on Performing an effective Presentation. It was a fun presentation and people very well received it. No matter on what subject, I present, I always end up talking about SQL. Here are two of the questions I had received during the event. Q1) I want to install SQL Server on my development server, where can we get it for free or at an economical price (I do not have MSDN)? A1) If you are not going to use your server in a production environment, you can just get SQL Server Developer’s Edition and you can read more about it over here. Here is another favorite question which I keep on receiving it during the event. Q2) I already have SQL Server installed on my machine, what are different feature pack should I install and where can I get them from. A2) Just download and install Microsoft SQL Server 2014 Service Pack. Here is the link for downloading it. The Microsoft SQL Server 2014 Feature Pack is a collection of stand-alone packages which provide additional value for Microsoft SQL Server. It includes tool and components for Microsoft SQL Server 2014 and add-on providers for Microsoft SQL Server 2014. Here is the list of component this product contains: Microsoft SQL Server Backup to Windows Azure Tool Microsoft SQL Server Cloud Adapter Microsoft Kerberos Configuration Manager for Microsoft SQL Server Microsoft SQL Server 2014 Semantic Language Statistics Microsoft SQL Server Data-Tier Application Framework Microsoft SQL Server 2014 Transact-SQL Language Service Microsoft Windows PowerShell Extensions for Microsoft SQL Server 2014 Microsoft SQL Server 2014 Shared Management Objects Microsoft Command Line Utilities 11 for Microsoft SQL Server Microsoft ODBC Driver 11 for Microsoft SQL Server – Windows Microsoft JDBC Driver 4.0 for Microsoft SQL Server Microsoft Drivers 3.0 for PHP for Microsoft SQL Server Microsoft SQL Server 2014 Transact-SQL ScriptDom Microsoft SQL Server 2014 Transact-SQL Compiler Service Microsoft System CLR Types for Microsoft SQL Server 2014 Microsoft SQL Server 2014 Remote Blob Store SQL RBS codeplex samples page SQL Server Remote Blob Store blogs Microsoft SQL Server Service Broker External Activator for Microsoft SQL Server 2014 Microsoft OData Source for Microsoft SQL Server 2014 Microsoft Balanced Data Distributor for Microsoft SQL Server 2014 Microsoft Change Data Capture Designer and Service for Oracle by Attunity for Microsoft SQL Server 2014 Microsoft SQL Server 2014 Master Data Service Add-in for Microsoft Excel Microsoft SQL Server StreamInsight Microsoft Connector for SAP BW for Microsoft SQL Server 2014 Microsoft SQL Server Migration Assistant Microsoft SQL Server 2014 Upgrade Advisor Microsoft OLEDB Provider for DB2 v5.0 for Microsoft SQL Server 2014 Microsoft SQL Server 2014 PowerPivot for Microsoft SharePoint 2013 Microsoft SQL Server 2014 ADOMD.NET Microsoft Analysis Services OLE DB Provider for Microsoft SQL Server 2014 Microsoft SQL Server 2014 Analysis Management Objects Microsoft SQL Server Report Builder for Microsoft SQL Server 2014 Microsoft SQL Server 2014 Reporting Services Add-in for Microsoft SharePoint Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority News, T SQL

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  • Building a database installer with WiX, datadude and Visual Studio 2010

    - by jamiet
    Today I have been using Windows Installer XML (WiX) to build an installer (.msi file) that would install a SQL Server database on a server of my choosing; the source code for that database lives in datadude (a tool which you may know by one of quite a few other names). The basis for this work was a most excellent blog post by Duke Kamstra entitled Implementing a WIX installer that calls the GDR version of VSDBCMD.EXE which coves the delicate intricacies of doing this – particularly how to call Vsdbcmd.exe in a CustomAction. Unfortunately there are a couple of things wrong with Duke’s post: Searching for “datadude wix” didn’t turn it up in the first page of search results and hence it took me a long time to find it. And I knew that it existed. If someone else were after a post on using WiX with datadude its likely that they would never have come across Duke’s post and that would be a great shame because its the definitive post on the matter. It was written in October 2009 and had not been updated for Visual Studio 2010. Well, this blog post is an attempt to solve those problems. Hopefully I’ve solved the first one just by following a few of my blogging SEO tips while writing this blog post, in the rest of it I will explain how I took Duke’s code and updated it to work in Visual Studio 2010. If you need to build a database installer using WiX, datadude and Visual Studio 2010 then you still need to follow Duke’s blog post so go and do that now. Below are the amendments that I made that enabled the project to get built in Visual Studio 2010: In VS2010 datadude’s output files have changed from being called Database.<suffix> to <ProjectName>_Database.<suffix>. Duke’s code was referencing the old file name formats. Duke used $(var.SolutionDir) and relative paths to point to datadude artefacts I have replaced these with Votive Project References http://wix.sourceforge.net/manual-wix3/votive_project_references.htm I commented out all references to MicrosoftSqlTypesDbschema in DatabaseArtifacts.wxi. I don't think this is produced in VS2010 (I may be wrong about that but it wasn't in the output from my project) Similarly I commented out component MicrosoftSqlTypesDbschema in VsdbcmdArtifacts.wxi. It wasn't where Duke's code said it should have been so am assuming/hoping it isn't needed. Duke's ?define block to work out appropriate SrcArchPath actually wasn't working for me (i.e. <?if $(var.Platform)=x64 ?> was evaluating to false)  so I just took out the conditional stuff and declared the path explicitly to the “Program Files (x86)” path. The old code is still there though if you need to put it back. None of the <RegistrySearch> stuff is needed for VS2010 - so I commented it all out! Changed to use /manifest option rather than /model option on vsdbcmd.exe command-line. Personal preference is all! Added a new component in order to bundle along the vsdbcmd.exe.config file Made the install of the Custom Action dependent on the relevant feature being selected for install. This one is actually really important – deselecting the database feature for installation does not, by default, stop the CustomAction from executing and so would cause an error - so that scenario needs to be catered for I have made my amended solution available for download at: http://cid-550f681dad532637.office.live.com/self.aspx/Public/BlogShare/20110210/InstallMyDatabase.zip It contains two projects: the WiX project and the datadude project that is the source to be deployed (for demo purposes it only contains one table). I have also made the .msi available although in order that it gets through file blockers I changed the name from InstallMyDatabase.msi to InstallMyDatabase.ms_ – simply rename the file back once you have downloaded it from: http://cid-550f681dad532637.office.live.com/self.aspx/Public/BlogShare/20110210/InstallMyDatabase.ms%5E_ .You can try it out for yourself – the only thing it does is dump the files into %Program Files%\MyDatabase and uses them to install a database onto a server of your choosing with a name of your choosing - no damaging side-affects. I will caveat this by saying “it works on my machine” and, not having access to a plethora of different machines, I haven’t tested it anywhere else. One potential issue that I know of is that Vsdbcmd.exe has a dependency on SQL Server CE although if you have SQL Server tools or Visual Studio installed you should be fine. Unfortunately its not possible to bundle along the SQL Server CE installer in the .msi because Windows will not allow you to call one installer from inside another – the recommended way to get around this problem is to build a bootstrapper to bundle the whole lot together but doing that is outside the scope of this blog post. If you discover any other issues then please let me know. Here are the screenshots from the installer: And once installed…. Hope this is useful! @jamiet 

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  • Imperative Programming v/s Declarative Programming v/s Functional Programming

    - by kaleidoscope
    Imperative Programming :: Imperative programming is a programming paradigm that describes computation in terms of statements that change a program state. In much the same way as the imperative mood in natural languages expresses commands to take action, imperative programs define sequences of commands for the computer to perform. The focus is on what steps the computer should take rather than what the computer will do (ex. C, C++, Java). Declarative Programming :: Declarative programming is a programming paradigm that expresses the logic of a computation without describing its control flow. It attempts to minimize or eliminate side effects by describing what the program should accomplish, rather than describing how to go about accomplishing it. The focus is on what the computer should do rather than how it should do it (ex. SQL). A  C# example of declarative v/s. imperative programming is LINQ. With imperative programming, you tell the compiler what you want to happen, step by step. For example, let's start with this collection, and choose the odd numbers: List<int> collection = new List<int> { 1, 2, 3, 4, 5 }; With imperative programming, we'd step through this, and decide what we want: List<int> results = new List<int>(); foreach(var num in collection) {     if (num % 2 != 0)           results.Add(num); } Here’s what we are doing: *Create a result collection *Step through each number in the collection *Check the number, if it's odd, add it to the results With declarative programming, on the other hand, we write the code that describes what you want, but not necessarily how to get it var results = collection.Where( num => num % 2 != 0); Here, we're saying "Give us everything where it's odd", not "Step through the collection. Check this item, if it's odd, add it to a result collection." Functional Programming :: Functional programming is a programming paradigm that treats computation as the evaluation of mathematical functions and avoids state and mutable data. It emphasizes the application of functions.Functional programming has its roots in the lambda calculus. It is a subset of declarative languages that has heavy focus on recursion. Functional programming can be a mind-bender, which is one reason why Lisp, Scheme, and Haskell have never really surpassed C, C++, Java and COBOL in commercial popularity. But there are benefits to the functional way. For one, if you can get the logic correct, functional programming requires orders of magnitude less code than imperative programming. That means fewer points of failure, less code to test, and a more productive (and, many would say, happier) programming life. As systems get bigger, this has become more and more important. To know more : http://stackoverflow.com/questions/602444/what-is-functional-declarative-and-imperative-programming http://msdn.microsoft.com/en-us/library/bb669144.aspx http://en.wikipedia.org/wiki/Imperative_programming   Technorati Tags: Ranjit,Imperative Programming,Declarative programming,Functional Programming

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  • 2010 Collaboration Summit Impressions

    - by Elena Zannoni
    It's a bit late, but there you have it anyway. April 14 to 16 I attended the Linux Foundation Collaboration Summit in SFO. I was running two tracks, one on tracing and one on tools. You can see the tracks and the slides here: http://events.linuxfoundation.org/events/collaboration-summit/slides I was pretty busy both days, Thursday with a whole day tracing track, Friday with a half day toolchain track. The sessions were well attended, the rooms were full, with people spilling in the hallways. Some new things were presented, like Kernelshark, by Steve Rostedt, a GUI (yes, believe it or not, a GUI) written in GTK. It is very nice, showing a timeline for traced kernel events, and you can zoom in and filter at will. It works on the latest kernels, and it requires some new things/fixes in GTK. I don't recall exactly what version of GTK though. Dominique Toupin from Ericsson presented something about user requirements for tracing. Mostly though about who's who in the embedded world, and eclipse. Masami and Mathieu presented an update on their work. See their slides. The interesting thing to me was of course the new version of uprobes w/o underlying utrace presented by Jim Keniston. At the end of the session we had a discussion about the future of utrace. Roland wasn't there, butTom Tromey (also from RedHat) collected the feedback. Basically we are at a standstill now that utrace has been rejected yet again. There wasn't much advise that anybody could give, except jokingly, we decided that the only way in is to make it a part of perf events. There needs to be another refactoring, but most of all, this "killer app" that would be enabled because of utrace hasn't materialized yet. We think that having a good debugging story on Linux is enough of a killer app, for instance allowing multiple tracers, and not relying on SIGCHLD etc. I think this wasn't completely clear to the kernel community. Trying to achieve debugging via a gdb stub inside the kernel interfacing to utrace and that is controlled via the gdb remote protocol also lost its appeal (thankfully, since the gdb remote protocol is archaic). Somebody would have to be creative in how to submit utrace. It doesn't have to be called utrace (it was really a random choice, for lack of a letter that was not already used in front of the word "trace"). So basically, I think the ideas behind utrace are sound, and the necessity of a new interface is acknowledged. But I believe the integration/submission process with the kernel folks has to restart from scratch, clean slate. We'll see. There are many conferences and meetings coming up in the near future where things can be discussed further. On the second day, Friday, we had the tools talks. It was interesting to observe the more "kernel" oriented people's behavior towards the gcc etc community. The first talk was by Mark Mitchell, about Gcc and its new plugin architecture. After that, Paolo talked about the new C++1x standard, which will be finalized in 2011. Many features are already implemented in the libstdc++ library and gcc and usable today. We had a few minutes (really, the half day track was quite short) where Bradley Kuhn from the Software Freedom Law Center explained the GPLv3 exception for gcc (due to the new gcc plugin architecture and the availability of the intermediate results from the compilation, which is a new thing). I will not try to explain, but basically you cannot take the result of the preprocessing and then use that in your own proprietary compiler. After, we had a talk by Ian Taylor about the new Gold linker. One good thing in that area is that they are trying to make gold the new default linker (for instance Fedora will use gold as the distro linker). However gold is very different from binutils' old linker. It doesn't use a linker script, for instance. The kernel has been linked with gold many times as an exercise (the ground work was done by Kris Van Hees), but this needs to be constantly tested/monitored because the kernel linker script is very complex, and uses esoteric features (Wenji is now monitoring that each kernel RC can be built with gold). It was positive that people are now aware of gold and the need for it to be ported to more architectures. It seems that the porting is very easy, with little arch dependent code. Finally Tom Tromey presented about gdb and the archer project. Archer is a development branch of gdb mostly done by RedHat, where they are focusing on better c++ printing, c++ expression parsing, and plugins. The archer work is merged regularly in the gdb mainline. In general it was a good conference. I did miss most of the first day, because that's when I flew in. But I caught a couple of talks. Nothing earth shattering, except for Google giving each person registered a free Android phone. Yey.

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  • Change Comes from Within

    - by John K. Hines
    I am in the midst of witnessing a variety of teams moving away from Scrum. Some of them are doing things like replacing Scrum terms with more commonly understood terminology. Mainly they have gone back to using industry standard terms and more traditional processes like the RAPID decision making process. For example: Scrum Master becomes Project Lead. Scrum Team becomes Project Team. Product Owner becomes Stakeholders. I'm actually quite sad to see this happening, but I understand that Scrum is a radical change for most organizations. Teams are slowly but surely moving away from Scrum to a process that non-software engineers can understand and follow. Some could never secure the education or personnel (like a Product Owner) to get the whole team engaged. And many people with decision-making authority do not see the value in Scrum besides task planning and tracking. You see, Scrum cannot be mandated. No one can force a team to be Agile, collaborate, continuously improve, and self-reflect. Agile adoptions must start from a position of mutual trust and willingness to change. And most software teams aren't like that. Here is my personal epiphany from over a year of attempting to promote Agile on a small development team: The desire to embrace Agile methodologies must come from each and every member of the team. If this desire does not exist - if the team is satisfied with its current process, if the team is not motivated to improve, or if the team is afraid of change - the actual demonstration of all the benefits prescribed by Agile and Scrum will take years. I've read some blog posts lately that criticise Scrum for demanding "Big Change Up Front." One's opinion of software methodologies boils down to one's perspective. If you see modern software development as successful, you will advocate for small, incremental changes to how it is done. If you see it as broken, you'll be much more motivated to take risks and try something different. So my question to you is this - is modern software development healthy or in need of dramatic improvement? I can tell you from personal experience that any project that requires exploration, planning, development, stabilisation, and deployment is hard. Trying to make that process better with only a slightly modified approach is a mistake. You will become completely dependent upon the skillset of your team (the only variable you can change). But the difficulty of planned work isn't one of skill. It isn't until you solve the fundamental challenges of communication, collaboration, quality, and efficiency that skill even comes into play. So I advocate for Big Change Up Front. And I advocate for it to happen often until those involved can say, from experience, that it is no longer needed. I hope every engineer has the opportunity to see the benefits of Agile and Scrum on a highly functional team. I'll close with more key learnings that can help with a Scrum adoption: Your leaders must understand Scrum. They must understand software development, its inherent difficulties, and how Scrum helps. If you attempt to adopt Scrum before the understanding is there, your leaders will apply traditional solutions to your problems - often creating more problems. Success should be measured by quality, not revenue. Namely, the value of software to an organization is the revenue it generates minus ongoing support costs. You should identify quality-based metrics that show the effect Agile techniques have on your software. Motivation is everything. I finally understand why so many Agile advocates say you that if you are not on a team using Agile, you should leave and find one. Scrum and especially Agile encompass many elegant solutions to a wide variety of problems. If you are working on a team that has not encountered these problems the the team may never see the value in the solutions.   Having said all that, I'm not giving up on Agile or Scrum. I am convinced it is a better approach for software development. But reality is saying that its adoption is not straightforward and highly subject to disruption. Unless, that is, everyone really, really wants it.

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  • Subterranean IL: Filter exception handlers

    - by Simon Cooper
    Filter handlers are the second type of exception handler that aren't accessible from C#. Unlike the other handler types, which have defined conditions for when the handlers execute, filter lets you use custom logic to determine whether the handler should be run. However, similar to a catch block, the filter block does not get run if control flow exits the block without throwing an exception. Introducing filter blocks An example of a filter block in IL is the following: .try { // try block } filter { // filter block endfilter }{ // filter handler } or, in v1 syntax, TryStart: // try block TryEnd: FilterStart: // filter block HandlerStart: // filter handler HandlerEnd: .try TryStart to TryEnd filter FilterStart handler HandlerStart to HandlerEnd In the v1 syntax there is no end label specified for the filter block. This is because the filter block must come immediately before the filter handler; the end of the filter block is the start of the filter handler. The filter block indicates to the CLR whether the filter handler should be executed using a boolean value on the stack when the endfilter instruction is run; true/non-zero if it is to be executed, false/zero if it isn't. At the start of the filter block, and the corresponding filter handler, a reference to the exception thrown is pushed onto the stack as a raw object (you have to manually cast to System.Exception). The allowed IL inside a filter block is tightly controlled; you aren't allowed branches outside the block, rethrow instructions, and other exception handling clauses. You can, however, use call and callvirt instructions to call other methods. Filter block logic To demonstrate filter block logic, in this example I'm filtering on whether there's a particular key in the Data dictionary of the thrown exception: .try { // try block } filter { // Filter starts with exception object on stack // C# code: ((Exception)e).Data.Contains("MyExceptionDataKey") // only execute handler if Contains returns true castclass [mscorlib]System.Exception callvirt instance class [mscorlib]System.Collections.IDictionary [mscorlib]System.Exception::get_Data() ldstr "MyExceptionDataKey" callvirt instance bool [mscorlib]System.Collections.IDictionary::Contains(object) endfilter }{ // filter handler // Also starts off with exception object on stack callvirt instance string [mscorlib]System.Object::ToString() call void [mscorlib]System.Console::WriteLine(string) } Conclusion Filter exception handlers are another exception handler type that isn't accessible from C#, however, just like fault handlers, the behaviour can be replicated using a normal catch block: try { // try block } catch (Exception e) { if (!FilterLogic(e)) throw; // handler logic } So, it's not that great a loss, but it's still annoying that this functionality isn't directly accessible. Well, every feature starts off with minus 100 points, so it's understandable why something like this didn't make it into the C# compiler ahead of a different feature.

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  • jQuery Selector Tester and Cheat Sheet

    - by SGWellens
    I've always appreciated these tools: Expresso and XPath Builder. They make designing regular expressions and XPath selectors almost fun! Did I say fun? I meant less painful. Being able to paste/load text and then interactively play with the search criteria is infinitely better than the code/compile/run/test cycle. It's faster and you get a much better feel for how the expressions work. So, I decided to make my own interactive tool to test jQuery selectors:  jQuery Selector Tester.   Here's a sneak peek: Note: There are some existing tools you may like better: http://www.woods.iki.fi/interactive-jquery-tester.html http://www.w3schools.com/jquery/trysel.asp?filename=trysel_basic&jqsel=p.intro,%23choose My tool is different: It is one page. You can save it and run it locally without a Web Server. It shows the results as a list of iterated objects instead of highlighted html. A cheat sheet is on the same page as the tester which is handy. I couldn't upload an .htm or .html file to this site so I hosted it on my personal site here: jQuery Selector Tester. Design Highlights: To make the interactive search work, I added a hidden div to the page: <!--Hidden div holds DOM elements for jQuery to search--><div id="HiddenDiv" style="display: none"></div> When ready to search, the searchable html text is copied into the hidden div…this renders the DOM tree in the hidden div: // get the html to search, insert it to the hidden divvar Html = $("#TextAreaHTML").val();$("#HiddenDiv").html(Html); When doing a search, I modify the search pattern to look only in the HiddenDiv. To do that, I put a space between the patterns.  The space is the Ancestor operator (see the Cheat Sheet): // modify search string to only search in our// hidden div and do the searchvar SearchString = "#HiddenDiv " + SearchPattern;try{    var $FoundItems = $(SearchString);}   Big Fat Stinking Faux Pas: I was about to publish this article when I made a big mistake: I tested the tool with Mozilla FireFox. It blowed up…it blowed up real good. In the past I’ve only had to target IE so this was quite a revelation. When I started to learn JavaScript, I was disgusted to see all the browser dependent code. Who wants to spend their time testing against different browsers and versions of browsers? Adding a bunch of ‘if-else’ code is a tedious and thankless task. I avoided client code as much as I could. Then jQuery came along and all was good. It was browser independent and freed us from the tedium of worrying about version N of the Acme browser. Right? Wrong! I had used outerHTML to display the selected elements. The problem is Mozilla FireFox doesn’t implement outerHTML. I replaced this: // encode the html markupvar OuterHtml = $('<div/>').text(this.outerHTML).html(); With this: // encode the html markupvar Html = $('<div>').append(this).html();var OuterHtml = $('<div/>').text(Html).html(); Another problem was that Mozilla FireFox doesn’t implement srcElement. I replaced this: var Row = e.srcElement.parentNode;  With this: var Row = e.target.parentNode; Another problem was the indexing. The browsers have different ways of indexing. I replaced this: // this cell has the search pattern  var Cell = Row.childNodes[1];   // put the pattern in the search box and search                    $("#TextSearchPattern").val(Cell.innerText);  With this: // get the correct cell and the text in the cell// place the text in the seach box and serachvar Cell = $(Row).find("TD:nth-child(2)");var CellText = Cell.text();$("#TextSearchPattern").val(CellText);   So much for the myth of browser independence. Was I overly optimistic and gullible? I don’t think so. And when I get my millions from the deposed Nigerian prince I sent money to, you’ll see that having faith is not futile. Notes: My goal was to have a single standalone file. I tried to keep the features and CSS to a minimum–adding only enough to make it useful and visually pleasing. When testing, I often thought there was a problem with the jQuery selector. Invariable it was invalid html code. If your results aren't what you expect, don't assume it's the jQuery selector pattern: The html may be invalid. To help in development and testing, I added a double-click handler to the rows in the Cheat Sheet table. If you double-click a row, the search pattern is put in the search box, a search is performed and the page is scrolled so you can see the results. I left the test html and code in the page. If you are using a CDN (non-local) version of the jQuery libraray, the designer in Visual Studio becomes extremely slow.  That's why there are two version of the library in the header and one is commented out. For reference, here is the jQuery documentation on selectors: http://api.jquery.com/category/selectors/ Here is a much more comprehensive list of CSS selectors (which jQuery uses): http://www.w3.org/TR/CSS2/selector.html I hope someone finds this useful. Steve WellensCodeProject

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  • Getting Started with Prism (aka Composite Application Guidance for WPF and Silverlight)

    - by dotneteer
    Overview Prism is a framework from the Microsoft Patterns and Practice team that allow you to create WPF and Silverlight in a modular way. It is especially valuable for larger projects in which a large number of developers can develop in parallel. Prism achieves its goal by supplying several services: · Dependency Injection (DI) and Inversion of control (IoC): By using DI, Prism takes away the responsibility of instantiating and managing the life time of dependency objects from individual components to a container. Prism relies on containers to discover, manage and compose large number of objects. By varying the configuration, the container can also inject mock objects for unit testing. Out of the box, Prism supports Unity and MEF as container although it is possible to use other containers by subclassing the Bootstrapper class. · Modularity and Region: Prism supplies the framework to split application into modules from the application shell. Each module is a library project that contains both UI and code and is responsible to initialize itself when loaded by the shell. Each window can be further divided into regions. A region is a user control with associated model. · Model, view and view-model (MVVM) pattern: Prism promotes the user MVVM. The use of DI container makes it much easier to inject model into view. WPF already has excellent data binding and commanding mechanism. To be productive with Prism, it is important to understand WPF data binding and commanding well. · Event-aggregation: Prism promotes loosely coupled components. Prism discourages for components from different modules to communicate each other, thus leading to dependency. Instead, Prism supplies an event-aggregation mechanism that allows components to publish and subscribe events without knowing each other. Architecture In the following, I will go into a little more detail on the services provided by Prism. Bootstrapper In a typical WPF application, application start-up is controls by App.xaml and its code behind. The main window of the application is typically specified in the App.xaml file. In a Prism application, we start a bootstrapper in the App class and delegate the duty of main window to the bootstrapper. The bootstrapper will start a dependency-injection container so all future object instantiations are managed by the container. Out of box, Prism provides the UnityBootstrapper and MefUnityBootstrapper abstract classes. All application needs to either provide a concrete implementation of one of these bootstrappers, or alternatively, subclass the Bootstrapper class with another DI container. A concrete bootstrapper class must implement the CreateShell method. Its responsibility is to resolve and create the Shell object through the DI container to serve as the main window for the application. The other important method to override is ConfigureModuleCatalog. The bootstrapper can register modules for the application. In a more advance scenario, an application does not have to know all its modules at compile time. Modules can be discovered at run time. Readers to refer to one of the Open Modularity Quick Starts for more information. Modules Once modules are registered with or discovered by Prism, they are instantiated by the DI container and their Initialize method is called. The DI container can inject into a module a region registry that implements IRegionViewRegistry interface. The module, in its Initialize method, can then call RegisterViewWithRegion method of the registry to register its regions. Regions Regions, once registered, are managed by the RegionManager. The shell can then load regions either through the RegionManager.RegionName attached property or dynamically through code. When a view is created by the region manager, the DI container can inject view model and other services into the view. The view then has a reference to the view model through which it can interact with backend services. Service locator Although it is possible to inject services into dependent classes through a DI container, an alternative way is to use the ServiceLocator to retrieve a service on demard. Prism supplies a service locator implementation and it is possible to get an instance of the service by calling: ServiceLocator.Current.GetInstance<IServiceType>() Event aggregator Prism supplies an IEventAggregator interface and implementation that can be injected into any class that needs to communicate with each other in a loosely-coupled fashion. The event aggregator uses a publisher/subscriber model. A class can publishes an event by calling eventAggregator.GetEvent<EventType>().Publish(parameter) to raise an event. Other classes can subscribe the event by calling eventAggregator.GetEvent<EventType>().Subscribe(EventHandler, other options). Getting started The easiest way to get started with Prism is to go through the Prism Hands-On labs and look at the Hello World QuickStart. The Hello World QuickStart shows how bootstrapper, modules and region works. Next, I would recommend you to look at the Stock Trader Reference Implementation. It is a more in depth example that resemble we want to set up an application. Several other QuickStarts cover individual Prism services. Some scenarios, such as dynamic module discovery, are more advanced. Apart from the official prism document, you can get an overview by reading Glen Block’s MSDN Magazine article. I have found the best free training material is from the Boise Code Camp. To be effective with Prism, it is important to understands key concepts of WPF well first, such as the DependencyProperty system, data binding, resource, theme and ICommand. It is also important to know your DI container of choice well. I will try to explorer these subjects in depth in the future. Testimony Recently, I worked on a desktop WPF application using Prism. I had a wonderful experience with Prism. The Prism is flexible enough even in the presence of third party controls such as Telerik WPF controls. We have never encountered any significant obstacle.

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  • CLR via C# 3rd Edition is out

    - by Abhijeet Patel
    Time for some book news update. CLR via C#, 3rd Edition seems to have been out for a little while now. The book was released in early Feb this year, and needless to say my copy is on it’s way. I can barely wait to dig in and chew on the goodies that one of the best technical authors and software professionals I respect has in store. The 2nd edition of the book was an absolute treat and this edition promises to be no less. Here is a brief description of what’s new and updated from the 2nd edition. Part I – CLR Basics Chapter 1-The CLR’s Execution Model Added about discussion about C#’s /optimize and /debug switches and how they relate to each other. Chapter 2-Building, Packaging, Deploying, and Administering Applications and Types Improved discussion about Win32 manifest information and version resource information. Chapter 3-Shared Assemblies and Strongly Named Assemblies Added discussion of TypeForwardedToAttribute and TypeForwardedFromAttribute. Part II – Designing Types Chapter 4-Type Fundamentals No new topics. Chapter 5-Primitive, Reference, and Value Types Enhanced discussion of checked and unchecked code and added discussion of new BigInteger type. Also added discussion of C# 4.0’s dynamic primitive type. Chapter 6-Type and Member Basics No new topics. Chapter 7-Constants and Fields No new topics. Chapter 8-Methods Added discussion of extension methods and partial methods. Chapter 9-Parameters Added discussion of optional/named parameters and implicitly-typed local variables. Chapter 10-Properties Added discussion of automatically-implemented properties, properties and the Visual Studio debugger, object and collection initializers, anonymous types, the System.Tuple type and the ExpandoObject type. Chapter 11-Events Added discussion of events and thread-safety as well as showing a cool extension method to simplify the raising of an event. Chapter 12-Generics Added discussion of delegate and interface generic type argument variance. Chapter 13-Interfaces No new topics. Part III – Essential Types Chapter 14-Chars, Strings, and Working with Text No new topics. Chapter 15-Enums Added coverage of new Enum and Type methods to access enumerated type instances. Chapter 16-Arrays Added new section on initializing array elements. Chapter 17-Delegates Added discussion of using generic delegates to avoid defining new delegate types. Also added discussion of lambda expressions. Chapter 18-Attributes No new topics. Chapter 19-Nullable Value Types Added discussion on performance. Part IV – CLR Facilities Chapter 20-Exception Handling and State Management This chapter has been completely rewritten. It is now about exception handling and state management. It includes discussions of code contracts and constrained execution regions (CERs). It also includes a new section on trade-offs between writing productive code and reliable code. Chapter 21-Automatic Memory Management Added discussion of C#’s fixed state and how it works to pin objects in the heap. Rewrote the code for weak delegates so you can use them with any class that exposes an event (the class doesn’t have to support weak delegates itself). Added discussion on the new ConditionalWeakTable class, GC Collection modes, Full GC notifications, garbage collection modes and latency modes. I also include a new sample showing how your application can receive notifications whenever Generation 0 or 2 collections occur. Chapter 22-CLR Hosting and AppDomains Added discussion of side-by-side support allowing multiple CLRs to be loaded in a single process. Added section on the performance of using MarshalByRefObject-derived types. Substantially rewrote the section on cross-AppDomain communication. Added section on AppDomain Monitoring and first chance exception notifications. Updated the section on the AppDomainManager class. Chapter 23-Assembly Loading and Reflection Added section on how to deploy a single file with dependent assemblies embedded inside it. Added section comparing reflection invoke vs bind/invoke vs bind/create delegate/invoke vs C#’s dynamic type. Chapter 24-Runtime Serialization This is a whole new chapter that was not in the 2nd Edition. Part V – Threading Chapter 25-Threading Basics Whole new chapter motivating why Windows supports threads, thread overhead, CPU trends, NUMA Architectures, the relationship between CLR threads and Windows threads, the Thread class, reasons to use threads, thread scheduling and priorities, foreground thread vs background threads. Chapter 26-Performing Compute-Bound Asynchronous Operations Whole new chapter explaining the CLR’s thread pool. This chapter covers all the new .NET 4.0 constructs including cooperative cancelation, Tasks, the aralle class, parallel language integrated query, timers, how the thread pool manages its threads, cache lines and false sharing. Chapter 27-Performing I/O-Bound Asynchronous Operations Whole new chapter explaining how Windows performs synchronous and asynchronous I/O operations. Then, I go into the CLR’s Asynchronous Programming Model, my AsyncEnumerator class, the APM and exceptions, Applications and their threading models, implementing a service asynchronously, the APM and Compute-bound operations, APM considerations, I/O request priorities, converting the APM to a Task, the event-based Asynchronous Pattern, programming model soup. Chapter 28-Primitive Thread Synchronization Constructs Whole new chapter discusses class libraries and thread safety, primitive user-mode, kernel-mode constructs, and data alignment. Chapter 29-Hybrid Thread Synchronization Constructs Whole new chapter discussion various hybrid constructs such as ManualResetEventSlim, SemaphoreSlim, CountdownEvent, Barrier, ReaderWriterLock(Slim), OneManyResourceLock, Monitor, 3 ways to solve the double-check locking technique, .NET 4.0’s Lazy and LazyInitializer classes, the condition variable pattern, .NET 4.0’s concurrent collection classes, the ReaderWriterGate and SyncGate classes.

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  • Oracle Releases New Mainframe Re-Hosting in Oracle Tuxedo 11g

    - by Jason Williamson
    I'm excited to say that we've released our next generation of Re-hosting in 11g. In fact I'm doing some hands-on labs now for our Systems Integrators in Italy in a couple of weeks and targeting Latin America next month. If you are an SI, or Rehosting firm and are looking to become an Oracle Partner or get a better understanding of Tuxedo and how to use the workbench for rehosting...drop me a line. Oracle Tuxedo Application Runtime for CICS and Batch 11g provides a CICS API emulation and Batch environment that exploits the full range of Oracle Tuxedo's capabilities. Re-hosted applications run in a multi-node, grid environment with centralized production control. Also, enterprise integration of CICS application services benefits from an open and SOA-enabled framework. Key features include: CICS Application Runtime: Can run IBM CICS applications unchanged in an application grid, which enables the distribution of large workloads across multiple processors and nodes. This simplifies CICS administration and can scale to over 100,000 users and over 50,000 transactions per second. 3270 Terminal Server: Protects business users from change through support for tn3270 terminal emulation. Distributed CICS Resource Management: Simplifies deployment and administration by allowing customers to run CICS regions in a distributed configuration. Batch Application Runtime: Provides robust IBM JES-like job management that enables local or remote job submissions. In addition, distributed batch initiators can enable parallelization of jobs and support fail-over, shortening the batch window and helping to meet stringent SLAs. Batch Execution Environment: Helps to run IBM batch unchanged and also supports JCL functionality and all common batch utilities. Oracle Tuxedo Application Rehosting Workbench 11g provides a set of automated migration tools integrated around a central repository. The tools provide high precision which results in very low error rates and the ability to handle large applications. This enables less expensive, low-risk migration projects. Key capabilities include: Workbench Repository and Cataloguer: Ensures integrity of the migrated application assets through full dependency checking. The Cataloguer generates and maintains all relevant meta-data on source and target components. File Migrator: Supports reliable migration of datasets and flat files to an ISAM or Oracle Database 11g. This is done through the automated migration utilities for data unloading, reloading and validation. It also generates logical access functions to shield developers from data repository changes. DB2 Migrator: Similarly, this tool automates the migration of DB2 schema and data to Oracle Database 11g. COBOL Migrator: Supports migration of IBM mainframe COBOL assets (OLTP and Batch) to open systems. Adapts programs for compiler dialects and data access variations. JCL Migrator: Supports migration of IBM JCL jobs to a Tuxedo ART environment, maintaining the flow and characteristics of batch jobs.

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  • SQL SERVER – SSIS Parameters in Parent-Child ETL Architectures – Notes from the Field #040

    - by Pinal Dave
    [Notes from Pinal]: SSIS is very well explored subject, however, there are so many interesting elements when we read, we learn something new. A similar concept has been Parent-Child ETL architecture’s relationship in SSIS. Linchpin People are database coaches and wellness experts for a data driven world. In this 40th episode of the Notes from the Fields series database expert Tim Mitchell (partner at Linchpin People) shares very interesting conversation related to how to understand SSIS Parameters in Parent-Child ETL Architectures. In this brief Notes from the Field post, I will review the use of SSIS parameters in parent-child ETL architectures. A very common design pattern used in SQL Server Integration Services is one I call the parent-child pattern.  Simply put, this is a pattern in which packages are executed by other packages.  An ETL infrastructure built using small, single-purpose packages is very often easier to develop, debug, and troubleshoot than large, monolithic packages.  For a more in-depth look at parent-child architectures, check out my earlier blog post on this topic. When using the parent-child design pattern, you will frequently need to pass values from the calling (parent) package to the called (child) package.  In older versions of SSIS, this process was possible but not necessarily simple.  When using SSIS 2005 or 2008, or even when using SSIS 2012 or 2014 in package deployment mode, you would have to create package configurations to pass values from parent to child packages.  Package configurations, while effective, were not the easiest tool to work with.  Fortunately, starting with SSIS in SQL Server 2012, you can now use package parameters for this purpose. In the example I will use for this demonstration, I’ll create two packages: one intended for use as a child package, and the other configured to execute said child package.  In the parent package I’m going to build a for each loop container in SSIS, and use package parameters to pass in a value – specifically, a ClientID – for each iteration of the loop.  The child package will be executed from within the for each loop, and will create one output file for each client, with the source query and filename dependent on the ClientID received from the parent package. Configuring the Child and Parent Packages When you create a new package, you’ll see the Parameters tab at the package level.  Clicking over to that tab allows you to add, edit, or delete package parameters. As shown above, the sample package has two parameters.  Note that I’ve set the name, data type, and default value for each of these.  Also note the column entitled Required: this allows me to specify whether the parameter value is optional (the default behavior) or required for package execution.  In this example, I have one parameter that is required, and the other is not. Let’s shift over to the parent package briefly, and demonstrate how to supply values to these parameters in the child package.  Using the execute package task, you can easily map variable values in the parent package to parameters in the child package. The execute package task in the parent package, shown above, has the variable vThisClient from the parent package mapped to the pClientID parameter shown earlier in the child package.  Note that there is no value mapped to the child package parameter named pOutputFolder.  Since this parameter has the Required property set to False, we don’t have to specify a value for it, which will cause that parameter to use the default value we supplied when designing the child pacakge. The last step in the parent package is to create the for each loop container I mentioned earlier, and place the execute package task inside it.  I’m using an object variable to store the distinct client ID values, and I use that as the iterator for the loop (I describe how to do this more in depth here).  For each iteration of the loop, a different client ID value will be passed into the child package parameter. The final step is to configure the child package to actually do something meaningful with the parameter values passed into it.  In this case, I’ve modified the OleDB source query to use the pClientID value in the WHERE clause of the query to restrict results for each iteration to a single client’s data.  Additionally, I’ll use both the pClientID and pOutputFolder parameters to dynamically build the output filename. As shown, the pClientID is used in the WHERE clause, so we only get the current client’s invoices for each iteration of the loop. For the flat file connection, I’m setting the Connection String property using an expression that engages both of the parameters for this package, as shown above. Parting Thoughts There are many uses for package parameters beyond a simple parent-child design pattern.  For example, you can create standalone packages (those not intended to be used as a child package) and still use parameters.  Parameter values may be supplied to a package directly at runtime by a SQL Server Agent job, through the command line (via dtexec.exe), or through T-SQL. Also, you can also have project parameters as well as package parameters.  Project parameters work in much the same way as package parameters, but the parameters apply to all packages in a project, not just a single package. Conclusion Of the numerous advantages of using catalog deployment model in SSIS 2012 and beyond, package parameters are near the top of the list.  Parameters allow you to easily share values from parent to child packages, enabling more dynamic behavior and better code encapsulation. If you want me to take a look at your server and its settings, or if your server is facing any issue we can Fix Your SQL Server. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: Notes from the Field, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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  • Is there a better term than "smoothness" or "granularity" to describe this language feature?

    - by Chris Stevens
    One of the best things about programming is the abundance of different languages. There are general purpose languages like C++ and Java, as well as little languages like XSLT and AWK. When comparing languages, people often use things like speed, power, expressiveness, and portability as the important distinguishing features. There is one characteristic of languages I consider to be important that, so far, I haven't heard [or been able to come up with] a good term for: how well a language scales from writing tiny programs to writing huge programs. Some languages make it easy and painless to write programs that only require a few lines of code, e.g. task automation. But those languages often don't have enough power to solve large problems, e.g. GUI programming. Conversely, languages that are powerful enough for big problems often require far too much overhead for small problems. This characteristic is important because problems that look small at first frequently grow in scope in unexpected ways. If a programmer chooses a language appropriate only for small tasks, scope changes can require rewriting code from scratch in a new language. And if the programmer chooses a language with lots of overhead and friction to solve a problem that stays small, it will be harder for other people to use and understand than necessary. Rewriting code that works fine is the single most wasteful thing a programmer can do with their time, but using a bazooka to kill a mosquito instead of a flyswatter isn't good either. Here are some of the ways this characteristic presents itself. Can be used interactively - there is some environment where programmers can enter commands one by one Requires no more than one file - neither project files nor makefiles are required for running in batch mode Can easily split code across multiple files - files can refeence each other, or there is some support for modules Has good support for data structures - supports structures like arrays, lists, and especially classes Supports a wide variety of features - features like networking, serialization, XML, and database connectivity are supported by standard libraries Here's my take on how C#, Python, and shell scripting measure up. Python scores highest. Feature C# Python shell scripting --------------- --------- --------- --------------- Interactive poor strong strong One file poor strong strong Multiple files strong strong moderate Data structures strong strong poor Features strong strong strong Is there a term that captures this idea? If not, what term should I use? Here are some candidates. Scalability - already used to decribe language performance, so it's not a good idea to overload it in the context of language syntax Granularity - expresses the idea of being good just for big tasks versus being good for big and small tasks, but doesn't express anything about data structures Smoothness - expresses the idea of low friction, but doesn't express anything about strength of data structures or features Note: Some of these properties are more correctly described as belonging to a compiler or IDE than the language itself. Please consider these tools collectively as the language environment. My question is about how easy or difficult languages are to use, which depends on the environment as well as the language.

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  • List of Commonly Used Value Types in XNA Games

    - by Michael B. McLaughlin
    Most XNA programmers are concerned about generating garbage. More specifically about allocating GC-managed memory (GC stands for “garbage collector” and is both the name of the class that provides access to the garbage collector and an acronym for the garbage collector (as a concept) itself). Two of the major target platforms for XNA (Windows Phone 7 and Xbox 360) use variants of the .NET Compact Framework. On both variants, the GC runs under various circumstances (Windows Phone 7 and Xbox 360). Of concern to XNA programmers is the fact that it runs automatically after a fixed amount of GC-managed memory has been allocated (currently 1MB on both systems). Many beginning XNA programmers are unaware of what constitutes GC-managed memory, though. So here’s a quick overview. In .NET, there are two different “types” of types: value types and reference types. Only reference types are managed by the garbage collector. Value types are not managed by the garbage collector and are instead managed in other ways that are implementation dependent. For purposes of XNA programming, the important point is that they are not managed by the GC and thus do not, by themselves, increment that internal 1 MB allocation counter. (n.b. Structs are value types. If you have a struct that has a reference type as a member, then that reference type, when instantiated, will still be allocated in the GC-managed memory and will thus count against the 1 MB allocation counter. Putting it in a struct doesn’t change the fact that it gets allocated on the GC heap, but the struct itself is created outside of the GC’s purview). Both value types and reference types use the keyword ‘new’ to allocate a new instance of them. Sometimes this keyword is hidden by a method which creates new instances for you, e.g. XmlReader.Create. But the important thing to determine is whether or not you are dealing with a value types or a reference type. If it’s a value type, you can use the ‘new’ keyword to allocate new instances of that type without incrementing the GC allocation counter (except as above where it’s a struct with a reference type in it that is allocated by the constructor, but there are no .NET Framework or XNA Framework value types that do this so it would have to be a struct you created or that was in some third-party library you were using for that to even become an issue). The following is a list of most all of value types you are likely to use in a generic XNA game: AudioCategory (used with XACT; not available on WP7) AvatarExpression (Xbox 360 only, but exposed on Windows to ease Xbox development) bool BoundingBox BoundingSphere byte char Color DateTime decimal double any enum (System.Enum itself is a class, but all enums are value types such that there are no GC allocations for enums) float GamePadButtons GamePadCapabilities GamePadDPad GamePadState GamePadThumbSticks GamePadTriggers GestureSample int IntPtr (rarely but occasionally used in XNA) KeyboardState long Matrix MouseState nullable structs (anytime you see, e.g. int? something, that ‘?’ denotes a nullable struct, also called a nullable type) Plane Point Quaternion Ray Rectangle RenderTargetBinding sbyte (though I’ve never seen it used since most people would just use a short) short TimeSpan TouchCollection TouchLocation TouchPanelCapabilities uint ulong ushort Vector2 Vector3 Vector4 VertexBufferBinding VertexElement VertexPositionColor VertexPositionColorTexture VertexPositionNormalTexture VertexPositionTexture Viewport So there you have it. That’s not quite a complete list, mind you. For example: There are various structs in the .NET framework you might make use of. I left out everything from the Microsoft.Xna.Framework.Graphics.PackedVector namespace, since everything in there ventures into the realm of advanced XNA programming anyway (n.b. every single instantiable thing in that namespace is a struct and thus a value type; there are also two interfaces but interfaces cannot be instantiated at all and thus don’t figure in to this discussion). There are so many enums you’re likely to use (PlayerIndex, SpriteSortMode, SpriteEffects, SurfaceFormat, etc.) that including them would’ve flooded the list and reduced its utility. So I went with “any enum” and trust that you can figure out what the enums are (and it’s rare to use ‘new’ with an enum anyway). That list also doesn’t include any of the pre-defined static instances of some of the classes (e.g. BlendState.AlphaBlend, BlendState.Opaque, etc.) which are already allocated such that using them doesn’t cause any new allocations and therefore doesn’t increase that 1 MB counter. That list also has a few misleading things. VertexElement, VertexPositionColor, and all the other vertex types are structs. But you’re only likely to ever use them as an array (for use with VertexBuffer or DynamicVertexBuffer), and all arrays are reference types (even arrays of value types such as VertexPositionColor[ ] or int[ ]). * So that’s it for now. The note below may be a bit confusing (it deals with how the GC works and how arrays are managed in .NET). If so, you can probably safely ignore it for now but feel free to ask any questions regardless. * Arrays of value types (where the value type doesn’t contain any reference type members) are much faster for the GC to examine than arrays of reference types, so there is a definite benefit to using arrays of value types where it makes sense. But creating arrays of value types does cause the GC’s allocation counter to increase. Indeed, allocating a large array of a value type is one of the quickest ways to increment the allocation counter since a .NET array is a sequential block of memory. An array of reference types is just a sequential block of references (typically 4 bytes each) while an array of value types is a sequential block of instances of that type. So for an array of Vector3s it would be 12 bytes each since each float is 4 bytes and there are 3 in a Vector3; for an array of VertexPositionNormalTexture structs it would typically be 32 bytes each since it has two Vector3s and a Vector2. (Note that there are a few additional bytes taken up in the creation of an array, typically 12 but sometimes 16 or possibly even more, which depend on the implementation details of the array type on the particular platform the code is running on).

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  • ACORD LOMA Session Highlights Policy Administration Trends

    - by [email protected]
    Helen Pitts, senior product marketing manager for Oracle Insurance, attended and is blogging from the ACORD LOMA Insurance Forum this week. Above: Paul Vancheri, Chief Information Officer, Fidelity Investments Life Insurance Company. Vancheri gave a presentation during the ACORD LOMA Insurance Systems Forum about the key elements of modern policy administration systems and how insurers can mitigate risk during legacy system migrations to safely introduce new technologies. When I had a few particularly challenging honors courses in college my father, a long-time technology industry veteran, used to say, "If you don't know how to do something go ask the experts. Find someone who has been there and done that, don't be afraid to ask the tough questions, and apply and build upon what you learn." (Actually he still offers this same advice today.) That's probably why my favorite sessions at industry events, like the ACORD LOMA Insurance Forum this week, are those that include insight on industry trends and case studies from carriers who share their experiences and offer best practices based upon their own lessons learned. I had the opportunity to attend a particularly insightful session Wednesday as Craig Weber, senior vice president of Celent's Insurance practice, and Paul Vancheri, CIO of Fidelity Life Investments, presented, "Managing the Dynamic Insurance Landscape: Enabling Growth and Profitability with a Modern Policy Administration System." Policy Administration Trends Growing the business is the top issue when it comes to IT among both life and annuity and property and casualty carriers according to Weber. To drive growth and capture market share from competitors, carriers are looking to modernize their core insurance systems, with 65 percent of those CIOs participating in recent Celent research citing plans to replace their policy administration systems. Weber noted that there has been continued focus and investment, particularly in the last three years, by software and technology vendors to offer modern, rules-based, configurable policy administration solutions. He added that these solutions are continuing to evolve with the ongoing aim of helping carriers rapidly meet shifting business needs--whether it is to launch new products to market faster than the competition, adapt existing products to meet shifting consumer and /or regulatory demands, or to exit unprofitable markets. He closed by noting the top four trends for policy administration either in the process of being adopted today or on the not-so-distant horizon for the future: Underwriting and service desktops New business automation Convergence of ultra-configurable and domain content-rich systems Better usability and screen design Mitigating the Risk When Making the Decision to Modernize Third-party analyst research from advisory firms like Celent was a key part of the due diligence process for Fidelity as it sought a replacement for its legacy policy administration system back in 2005, according to Vancheri. The company's business opportunities were outrunning system capability. Its legacy system had not been upgraded in several years and was deficient from a functionality and currency standpoint. This was constraining the carrier's ability to rapidly configure and bring new and complex products to market. The company sought a new, modern policy administration system, one that would enable it to keep pace with rapid and often unexpected industry changes and ahead of the competition. A cross-functional team that included representatives from finance, actuarial, operations, client services and IT conducted an extensive selection process. This process included deep documentation review, pilot evaluations, demonstrations of required functionality and complex problem-solving, infrastructure integration capability, and the ability to meet the company's desired cost model. The company ultimately selected an adaptive policy administration system that met its requirements to: Deliver ease of use - eliminating paper and rework, while easing the burden on representatives to sell and service annuities Provide customer parity - offering Web-based capabilities in alignment with the company's focus on delivering a consistent customer experience across its business Deliver scalability, efficiency - enabling automation, while simplifying and standardizing systems across its technology stack Offer desired functionality - supporting Fidelity's product configuration / rules management philosophy, focus on customer service and technology upgrade requirements Meet cost requirements - including implementation, professional services and licenses fees and ongoing maintenance Deliver upon business requirements - enabling the ability to drive time to market for new products and flexibility to make changes Best Practices for Addressing Implementation Challenges Based upon lessons learned during the company's implementation, Vancheri advised carriers to evaluate staffing capabilities and cultural impacts, review business requirements to avoid rebuilding legacy processes, factor in dependent systems, and review policies and practices to secure customer data. His formula for success: upfront planning + clear requirements = precision execution. Achieving a Return on Investment Vancheri said the decision to replace their legacy policy administration system and deploy a modern, rules-based system--before the economic downturn occurred--has been integral in helping the company adapt to shifting market conditions, while enabling growth in its direct channel sales of variable annuities. Since deploying its new policy admin system, the company has reduced its average time to market for new products from 12-15 months to 4.5 months. The company has since migrated its other products to the new system and retired its legacy system, significantly decreasing its overall product development cycle. From a processing standpoint Vancheri noted the company has achieved gains in automation, information, and ease of use, resulting in improved real-time data edits, controls for better quality, and tax handling capability. Plus, with by having only one platform to manage, the company has simplified its IT environment and is well positioned to deliver system enhancements for greater efficiencies. Commitment to Continuing the Investment In the short and longer term future Vancheri said the company plans to enhance business functionality to support money movement, wire automation, divorce processing on payout contracts and cost-based tracking improvements. It also plans to continue system upgrades to remain current as well as focus on further reducing cycle time, driving down maintenance costs, and integrating with other products. Helen Pitts is senior product marketing manager for Oracle Insurance focused on life/annuities and enterprise document automation.

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  • User Productivity Kit - Powerful Packages (Part 2)

    - by [email protected]
    In my first post on packages I described what a package is and how it can be used. I also started explaining some of the considerations that should be taken into account when determining how to arrange your packages. The first is when the files are interrelated and depend on one another such as an HTML file and it's graphics. A second consideration is how the files are used in your outlines. Let's say you're using a dozen Word doc files. You could place them all in a single package or put each Word doc file in a separate package but what's the right thing to do? There are several factors that will influence your decision. To understand the first, let me explain a function of UPK publishing. Take an outline in UPK that has an attachment (concept, frame link, or hyperlink) that points to a file in a package. When you publish this outline, the publishing engine will determine that there is a link to a file in the package and copy the contents of the package to the publishing destination directory. This is done to ensure that any interrelated files are kept together. For the situation where you have an HTML file with links to number of graphics files, this is a good thing. If, however, the package has a dozen unrelated Word doc files and you link to only one of them, all dozen Word documents will be copied to the publishing destination directory.  Whether or not this is a good thing is dependent on two things. First, are all of the files in the package used in the outline that you're publishing? Take an outline that includes links to all of the Word documents in that dozen document package I described earlier. For this situation, you may choose to keep all the files in a single package for convenience. A second consideration is how your organization leverages reuse in UPK. In this context, I'm referring to the link style of reuse such as when you link to the same topic from multiple UPK outlines and changes to the topic appear in both places. Take an example where you have the earlier mentioned dozen Word document package and an outline with a dozen topics in it. Each topic has an attachment pointing to one of the Word documents in the package (frame link, concept, etc.) If you're only publishing this outline, the single package probably works fine but what if you're reusing one of these topics in another outline? As I explained earlier, linking to one file in the package will result in all files in the package being copied to your published output. In this example, linking to one topic in the first outline will result in all dozen Word documents being copied to the published output. This may result in files in the output that you don't want there for business or size reasons. This is a situation in which you should consider placing each of the Word documents in it's own separate package. With each document in it's own package, that link to a single document will result in only that single package and single Word document being copied to the published output. In my last post I had described that packages are documents in the UPK library. When using the multi-user version of the UPK Developer you can leverage standard library capabilities for managing the files in these packages during the development process - capabilities such as check in / check out, history, etc. When structuring your packages take into consideration how the authors are going to be adding, modifying and deleting files from the packages. A single package is a single document in the UPK library. Like any other document in the library, a single user can check out the package and edit it at a time. If you have a large number of files in a single package and these must be modified by many users, you need to consider whether this will cause problems as multiple users compete to update the same package. If the files don't depend on each other consider placing the files in separate packages to reduce contention. I hope you've enjoyed these two posts on how you can leverage the power of packages in your content. In summary, consider the following when structuring your packages: Is the asset a single, standalone file or a set of files that depend on each other? Will all the files always be used together in a single outline or may only some of the files be needed based on how the content is reused across multiple outlines? Will multiple developers need to update the files in a single package or should you break it into multiple packages to reduce contention when checking out the document? We'd like to hear from you on how you're using packages in your content. Please add your comments below! Thank you and I hope these two posts have given you additional insights into how to use packages in your content and structure them for efficient use. John Zaums Senior Director, Product Development Oracle User Productivity Kit

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  • PTLQueue : a scalable bounded-capacity MPMC queue

    - by Dave
    Title: Fast concurrent MPMC queue -- I've used the following concurrent queue algorithm enough that it warrants a blog entry. I'll sketch out the design of a fast and scalable multiple-producer multiple-consumer (MPSC) concurrent queue called PTLQueue. The queue has bounded capacity and is implemented via a circular array. Bounded capacity can be a useful property if there's a mismatch between producer rates and consumer rates where an unbounded queue might otherwise result in excessive memory consumption by virtue of the container nodes that -- in some queue implementations -- are used to hold values. A bounded-capacity queue can provide flow control between components. Beware, however, that bounded collections can also result in resource deadlock if abused. The put() and take() operators are partial and wait for the collection to become non-full or non-empty, respectively. Put() and take() do not allocate memory, and are not vulnerable to the ABA pathologies. The PTLQueue algorithm can be implemented equally well in C/C++ and Java. Partial operators are often more convenient than total methods. In many use cases if the preconditions aren't met, there's nothing else useful the thread can do, so it may as well wait via a partial method. An exception is in the case of work-stealing queues where a thief might scan a set of queues from which it could potentially steal. Total methods return ASAP with a success-failure indication. (It's tempting to describe a queue or API as blocking or non-blocking instead of partial or total, but non-blocking is already an overloaded concurrency term. Perhaps waiting/non-waiting or patient/impatient might be better terms). It's also trivial to construct partial operators by busy-waiting via total operators, but such constructs may be less efficient than an operator explicitly and intentionally designed to wait. A PTLQueue instance contains an array of slots, where each slot has volatile Turn and MailBox fields. The array has power-of-two length allowing mod/div operations to be replaced by masking. We assume sensible padding and alignment to reduce the impact of false sharing. (On x86 I recommend 128-byte alignment and padding because of the adjacent-sector prefetch facility). Each queue also has PutCursor and TakeCursor cursor variables, each of which should be sequestered as the sole occupant of a cache line or sector. You can opt to use 64-bit integers if concerned about wrap-around aliasing in the cursor variables. Put(null) is considered illegal, but the caller or implementation can easily check for and convert null to a distinguished non-null proxy value if null happens to be a value you'd like to pass. Take() will accordingly convert the proxy value back to null. An advantage of PTLQueue is that you can use atomic fetch-and-increment for the partial methods. We initialize each slot at index I with (Turn=I, MailBox=null). Both cursors are initially 0. All shared variables are considered "volatile" and atomics such as CAS and AtomicFetchAndIncrement are presumed to have bidirectional fence semantics. Finally T is the templated type. I've sketched out a total tryTake() method below that allows the caller to poll the queue. tryPut() has an analogous construction. Zebra stripping : alternating row colors for nice-looking code listings. See also google code "prettify" : https://code.google.com/p/google-code-prettify/ Prettify is a javascript module that yields the HTML/CSS/JS equivalent of pretty-print. -- pre:nth-child(odd) { background-color:#ff0000; } pre:nth-child(even) { background-color:#0000ff; } border-left: 11px solid #ccc; margin: 1.7em 0 1.7em 0.3em; background-color:#BFB; font-size:12px; line-height:65%; " // PTLQueue : Put(v) : // producer : partial method - waits as necessary assert v != null assert Mask = 1 && (Mask & (Mask+1)) == 0 // Document invariants // doorway step // Obtain a sequence number -- ticket // As a practical concern the ticket value is temporally unique // The ticket also identifies and selects a slot auto tkt = AtomicFetchIncrement (&PutCursor, 1) slot * s = &Slots[tkt & Mask] // waiting phase : // wait for slot's generation to match the tkt value assigned to this put() invocation. // The "generation" is implicitly encoded as the upper bits in the cursor // above those used to specify the index : tkt div (Mask+1) // The generation serves as an epoch number to identify a cohort of threads // accessing disjoint slots while s-Turn != tkt : Pause assert s-MailBox == null s-MailBox = v // deposit and pass message Take() : // consumer : partial method - waits as necessary auto tkt = AtomicFetchIncrement (&TakeCursor,1) slot * s = &Slots[tkt & Mask] // 2-stage waiting : // First wait for turn for our generation // Acquire exclusive "take" access to slot's MailBox field // Then wait for the slot to become occupied while s-Turn != tkt : Pause // Concurrency in this section of code is now reduced to just 1 producer thread // vs 1 consumer thread. // For a given queue and slot, there will be most one Take() operation running // in this section. // Consumer waits for producer to arrive and make slot non-empty // Extract message; clear mailbox; advance Turn indicator // We have an obvious happens-before relation : // Put(m) happens-before corresponding Take() that returns that same "m" for T v = s-MailBox if v != null : s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 // unlock slot to admit next producer and consumer return v Pause tryTake() : // total method - returns ASAP with failure indication for auto tkt = TakeCursor slot * s = &Slots[tkt & Mask] if s-Turn != tkt : return null T v = s-MailBox // presumptive return value if v == null : return null // ratify tkt and v values and commit by advancing cursor if CAS (&TakeCursor, tkt, tkt+1) != tkt : continue s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 return v The basic idea derives from the Partitioned Ticket Lock "PTL" (US20120240126-A1) and the MultiLane Concurrent Bag (US8689237). The latter is essentially a circular ring-buffer where the elements themselves are queues or concurrent collections. You can think of the PTLQueue as a partitioned ticket lock "PTL" augmented to pass values from lock to unlock via the slots. Alternatively, you could conceptualize of PTLQueue as a degenerate MultiLane bag where each slot or "lane" consists of a simple single-word MailBox instead of a general queue. Each lane in PTLQueue also has a private Turn field which acts like the Turn (Grant) variables found in PTL. Turn enforces strict FIFO ordering and restricts concurrency on the slot mailbox field to at most one simultaneous put() and take() operation. PTL uses a single "ticket" variable and per-slot Turn (grant) fields while MultiLane has distinct PutCursor and TakeCursor cursors and abstract per-slot sub-queues. Both PTL and MultiLane advance their cursor and ticket variables with atomic fetch-and-increment. PTLQueue borrows from both PTL and MultiLane and has distinct put and take cursors and per-slot Turn fields. Instead of a per-slot queues, PTLQueue uses a simple single-word MailBox field. PutCursor and TakeCursor act like a pair of ticket locks, conferring "put" and "take" access to a given slot. PutCursor, for instance, assigns an incoming put() request to a slot and serves as a PTL "Ticket" to acquire "put" permission to that slot's MailBox field. To better explain the operation of PTLQueue we deconstruct the operation of put() and take() as follows. Put() first increments PutCursor obtaining a new unique ticket. That ticket value also identifies a slot. Put() next waits for that slot's Turn field to match that ticket value. This is tantamount to using a PTL to acquire "put" permission on the slot's MailBox field. Finally, having obtained exclusive "put" permission on the slot, put() stores the message value into the slot's MailBox. Take() similarly advances TakeCursor, identifying a slot, and then acquires and secures "take" permission on a slot by waiting for Turn. Take() then waits for the slot's MailBox to become non-empty, extracts the message, and clears MailBox. Finally, take() advances the slot's Turn field, which releases both "put" and "take" access to the slot's MailBox. Note the asymmetry : put() acquires "put" access to the slot, but take() releases that lock. At any given time, for a given slot in a PTLQueue, at most one thread has "put" access and at most one thread has "take" access. This restricts concurrency from general MPMC to 1-vs-1. We have 2 ticket locks -- one for put() and one for take() -- each with its own "ticket" variable in the form of the corresponding cursor, but they share a single "Grant" egress variable in the form of the slot's Turn variable. Advancing the PutCursor, for instance, serves two purposes. First, we obtain a unique ticket which identifies a slot. Second, incrementing the cursor is the doorway protocol step to acquire the per-slot mutual exclusion "put" lock. The cursors and operations to increment those cursors serve double-duty : slot-selection and ticket assignment for locking the slot's MailBox field. At any given time a slot MailBox field can be in one of the following states: empty with no pending operations -- neutral state; empty with one or more waiting take() operations pending -- deficit; occupied with no pending operations; occupied with one or more waiting put() operations -- surplus; empty with a pending put() or pending put() and take() operations -- transitional; or occupied with a pending take() or pending put() and take() operations -- transitional. The partial put() and take() operators can be implemented with an atomic fetch-and-increment operation, which may confer a performance advantage over a CAS-based loop. In addition we have independent PutCursor and TakeCursor cursors. Critically, a put() operation modifies PutCursor but does not access the TakeCursor and a take() operation modifies the TakeCursor cursor but does not access the PutCursor. This acts to reduce coherence traffic relative to some other queue designs. It's worth noting that slow threads or obstruction in one slot (or "lane") does not impede or obstruct operations in other slots -- this gives us some degree of obstruction isolation. PTLQueue is not lock-free, however. The implementation above is expressed with polite busy-waiting (Pause) but it's trivial to implement per-slot parking and unparking to deschedule waiting threads. It's also easy to convert the queue to a more general deque by replacing the PutCursor and TakeCursor cursors with Left/Front and Right/Back cursors that can move either direction. Specifically, to push and pop from the "left" side of the deque we would decrement and increment the Left cursor, respectively, and to push and pop from the "right" side of the deque we would increment and decrement the Right cursor, respectively. We used a variation of PTLQueue for message passing in our recent OPODIS 2013 paper. ul { list-style:none; padding-left:0; padding:0; margin:0; margin-left:0; } ul#myTagID { padding: 0px; margin: 0px; list-style:none; margin-left:0;} -- -- There's quite a bit of related literature in this area. I'll call out a few relevant references: Wilson's NYU Courant Institute UltraComputer dissertation from 1988 is classic and the canonical starting point : Operating System Data Structures for Shared-Memory MIMD Machines with Fetch-and-Add. Regarding provenance and priority, I think PTLQueue or queues effectively equivalent to PTLQueue have been independently rediscovered a number of times. See CB-Queue and BNPBV, below, for instance. But Wilson's dissertation anticipates the basic idea and seems to predate all the others. Gottlieb et al : Basic Techniques for the Efficient Coordination of Very Large Numbers of Cooperating Sequential Processors Orozco et al : CB-Queue in Toward high-throughput algorithms on many-core architectures which appeared in TACO 2012. Meneghin et al : BNPVB family in Performance evaluation of inter-thread communication mechanisms on multicore/multithreaded architecture Dmitry Vyukov : bounded MPMC queue (highly recommended) Alex Otenko : US8607249 (highly related). John Mellor-Crummey : Concurrent queues: Practical fetch-and-phi algorithms. Technical Report 229, Department of Computer Science, University of Rochester Thomasson : FIFO Distributed Bakery Algorithm (very similar to PTLQueue). Scott and Scherer : Dual Data Structures I'll propose an optimization left as an exercise for the reader. Say we wanted to reduce memory usage by eliminating inter-slot padding. Such padding is usually "dark" memory and otherwise unused and wasted. But eliminating the padding leaves us at risk of increased false sharing. Furthermore lets say it was usually the case that the PutCursor and TakeCursor were numerically close to each other. (That's true in some use cases). We might still reduce false sharing by incrementing the cursors by some value other than 1 that is not trivially small and is coprime with the number of slots. Alternatively, we might increment the cursor by one and mask as usual, resulting in a logical index. We then use that logical index value to index into a permutation table, yielding an effective index for use in the slot array. The permutation table would be constructed so that nearby logical indices would map to more distant effective indices. (Open question: what should that permutation look like? Possibly some perversion of a Gray code or De Bruijn sequence might be suitable). As an aside, say we need to busy-wait for some condition as follows : "while C == 0 : Pause". Lets say that C is usually non-zero, so we typically don't wait. But when C happens to be 0 we'll have to spin for some period, possibly brief. We can arrange for the code to be more machine-friendly with respect to the branch predictors by transforming the loop into : "if C == 0 : for { Pause; if C != 0 : break; }". Critically, we want to restructure the loop so there's one branch that controls entry and another that controls loop exit. A concern is that your compiler or JIT might be clever enough to transform this back to "while C == 0 : Pause". You can sometimes avoid this by inserting a call to a some type of very cheap "opaque" method that the compiler can't elide or reorder. On Solaris, for instance, you could use :"if C == 0 : { gethrtime(); for { Pause; if C != 0 : break; }}". It's worth noting the obvious duality between locks and queues. If you have strict FIFO lock implementation with local spinning and succession by direct handoff such as MCS or CLH,then you can usually transform that lock into a queue. Hidden commentary and annotations - invisible : * And of course there's a well-known duality between queues and locks, but I'll leave that topic for another blog post. * Compare and contrast : PTLQ vs PTL and MultiLane * Equivalent : Turn; seq; sequence; pos; position; ticket * Put = Lock; Deposit Take = identify and reserve slot; wait; extract & clear; unlock * conceptualize : Distinct PutLock and TakeLock implemented as ticket lock or PTL Distinct arrival cursors but share per-slot "Turn" variable provides exclusive role-based access to slot's mailbox field put() acquires exclusive access to a slot for purposes of "deposit" assigns slot round-robin and then acquires deposit access rights/perms to that slot take() acquires exclusive access to slot for purposes of "withdrawal" assigns slot round-robin and then acquires withdrawal access rights/perms to that slot At any given time, only one thread can have withdrawal access to a slot at any given time, only one thread can have deposit access to a slot Permissible for T1 to have deposit access and T2 to simultaneously have withdrawal access * round-robin for the purposes of; role-based; access mode; access role mailslot; mailbox; allocate/assign/identify slot rights; permission; license; access permission; * PTL/Ticket hybrid Asymmetric usage ; owner oblivious lock-unlock pairing K-exclusion add Grant cursor pass message m from lock to unlock via Slots[] array Cursor performs 2 functions : + PTL ticket + Assigns request to slot in round-robin fashion Deconstruct protocol : explication put() : allocate slot in round-robin fashion acquire PTL for "put" access store message into slot associated with PTL index take() : Acquire PTL for "take" access // doorway step seq = fetchAdd (&Grant, 1) s = &Slots[seq & Mask] // waiting phase while s-Turn != seq : pause Extract : wait for s-mailbox to be full v = s-mailbox s-mailbox = null Release PTL for both "put" and "take" access s-Turn = seq + Mask + 1 * Slot round-robin assignment and lock "doorway" protocol leverage the same cursor and FetchAdd operation on that cursor FetchAdd (&Cursor,1) + round-robin slot assignment and dispersal + PTL/ticket lock "doorway" step waiting phase is via "Turn" field in slot * PTLQueue uses 2 cursors -- put and take. Acquire "put" access to slot via PTL-like lock Acquire "take" access to slot via PTL-like lock 2 locks : put and take -- at most one thread can access slot's mailbox Both locks use same "turn" field Like multilane : 2 cursors : put and take slot is simple 1-capacity mailbox instead of queue Borrow per-slot turn/grant from PTL Provides strict FIFO Lock slot : put-vs-put take-vs-take at most one put accesses slot at any one time at most one put accesses take at any one time reduction to 1-vs-1 instead of N-vs-M concurrency Per slot locks for put/take Release put/take by advancing turn * is instrumental in ... * P-V Semaphore vs lock vs K-exclusion * See also : FastQueues-excerpt.java dice-etc/queue-mpmc-bounded-blocking-circular-xadd/ * PTLQueue is the same as PTLQB - identical * Expedient return; ASAP; prompt; immediately * Lamport's Bakery algorithm : doorway step then waiting phase Threads arriving at doorway obtain a unique ticket number Threads enter in ticket order * In the terminology of Reed and Kanodia a ticket lock corresponds to the busy-wait implementation of a semaphore using an eventcount and a sequencer It can also be thought of as an optimization of Lamport's bakery lock was designed for fault-tolerance rather than performance Instead of spinning on the release counter, processors using a bakery lock repeatedly examine the tickets of their peers --

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  • Does using GCC specific builtins qualify as incorporation within a project?

    - by DavidJFelix
    I understand that linking to a program licensed under the GPL requires that you release the source of your program under the GPL as well, while the LGPL does not require this. The terminology of the (L)GPL is very clear about this. #include "gpl_program.h" means you'd have to license GPL, because you're linking to GPL licensed code. And #include "lgpl_program.h" means you're free to license however you want, so that it doesn't explicitly prohibit linking to LGPL source. Now, my question about what isn't clear is: [begin question] GCC is GPL licensed, compiling with GCC, does not constitute "integration" into your program, as the GPL puts it; does using builtin functions (which are specific to GCC) constitute "incorporation" even though you haven't explicitly linked to this GPL licensed code? My intuition tells me that this isn't the intention, but legality isn't always intuitive. I'm not actually worried, but I'm curious if this could be considered the case. [end question] [begin aside] The reason for my equivocation is that GCC builtins like __builtin_clzl() or __builtin_expect() are an API technically and could be implemented in another way. For example, many builtins were replicated by LLVM and the argument could be made that it's not implementation specific to GCC. However, many builtins have no parallel and when compiled will link GPL licensed code in GCC and will not compile on other compilers. If you make the argument here that the API could be replicated by another compiler, couldn't you make that identical claim about any program you link to, so long as you don't distribute that source? I understand that I'm being a legal snake about this, but it strikes me as odd that the GPL isn't more specific. I don't see this as a reasonable ploy for proprietary software creators to bypass the GPL, as they'd have to bundle the GPL software to make it work, removing their plausible deniability. However, isn't it possible that if builtins don't constitute linking, then open source proponents who oppose the GPL could simply write a BSD/MIT/Apache/Apple licensed product that links to a GPL'd program and claim that they intend to write a non-GPL interface that is identical to the GPL one, preserving their BSD license until it's actually compiled? [end aside] Sorry for the aside, I didn't think many people would follow why I care about this if I'm not facing any legal trouble or implications. Don't worry too much about the hypotheticals there, I'm just extrapolating what either answer to my actual question could imply.

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  • Cross-platform independent development

    - by Joe Wreschnig
    Some years ago, if you wrote in C and some subset of C++ and used a sufficient number of platform abstractions (via SDL or whatever), you could run on every platform an indie could get on - Linux, Windows, Mac OS of various versions, obscure stuff like BeOS, and the open consoles like the GP2X and post-death Dreamcast. If you got a contract for a closed platform at some point, you could port your game to that platform with "minimal" code changes as well. Today, indie developers must use XNA to get on the Xbox 360 (and upcoming Windows phone); must not use XNA to work anywhere else but Windows; until recently had to use Java on Android; Flash doesn't run on phones, HTML5 doesn't work on IE. Unlike e.g. DirectX vs. OpenGL or Windows vs. Unix, these are changes to the core language you write your code in and can't be papered over without, basically, writing a compiler. You can move some game logic into scripts and include an interpreter - except when you can't, because the iPhone SDK doesn't allow it, and performance suffers because no one allows JIT. So what can you do if you want a really cross-platform portable game, or even just a significant body of engine and logic code? Is this not a problem because the platforms have fundamentally diverged - it's just plain not worthwhile to try to target both an iPhone and the Xbox 360 with any shared code because such a game would be bad? (I find this very unlikely. I can easily see wanting to share a game between a Windows Mobile phone and an Android, or an Xbox 360 and an iPad.) Are interfaces so high-level now that porting time is negligible? (I might believe this for business applications, but not for games with strict performance requirements.) Is this going to become more pronounced in the future? Is the split going to be, somewhat scarily, still down vendor lines? Will we all rely on high-level middleware like Flash or Unity to get anything cross-platform done? tl;dr - Is porting a problem, is it going to be a bigger problem in the future, and if so how do we solve it?

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  • Visual Studio 2010 and Target Framework Version

    - by Scott Dorman
    Almost two years ago, I wrote about a Visual Studio macro that allows you to change the Target Framework version of all projects in a solution. If you don’t know, the Target Framework version is what tells the compiler which version of the .NET Framework to compile against (more information is available here) and can be set to one of the following values: .NET Framework 2.0 .NET Framework 3.0 .NET Framework 3.5 .NET Framework 3.5 Client Profile .NET Framework 4.0 .NET Framework 4.0 Client Profile This can be easily accomplished by editing the project properties: The problem with this approach is that if you need to change a lot of projects at one time it becomes rather unwieldy. One possible solution is to edit the project files by hand in a text editor and change the <TargetFrameworkVersion /> and <TargetFrameworkProfile /> properties to the correct values. For example, for the .NET Framework 4.0 Client Profile, these values would be: <TargetFrameworkVersion>v4.0</TargetFrameworkVersion> <TargetFrameworkProfile>Client</TargetFrameworkProfile> Again, this is not only time consuming but can also be error-prone. The better solution is to automate this through the use of a Visual Studio macro. Since I had already created a macro to do this for Visual Studio 2008, I updated that macro to work with Visual Studio 2010 and .NET 4.0. It prompts you for the target framework version you want to set for all of the projects and then loops through each project in the solution and makes the change. If you select one of the Framework versions that support a Client Profile, it will ask if you want to use the Client Profile or the Full Profile. It is smart enough to skip project types that don’t support this property and projects that are already at the correct version. This version also incorporates the changes suggested by George (in the comments). The macro is available on my SkyDrive account. Download it to your <UserProfile>\Documents\Visual Studio 2010\Projects\VSMacros80\MyMacros folder, open the Visual Studio Macro IDE (Alt-F11) and add it as an existing item to the “MyMacros” project. I make no guarantees or warranties on this macro. I have tested it on several solutions and projects and everything seems to work and not cause any problems, but, as always, use with caution. Since it is a macro, you have the full source code available to investigate and see what it’s actually doing. If you find any bugs or make any useful changes, please let me know and I’ll update the macro. Technorati Tags: Macros,Visual Studio

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  • Keep it Professional &ndash; Multiple Environments

    - by AjarnMark
    I have certainly been reading blogs a whole lot more than writing them the last several weeks, and it’s about time I got back to writing.  I have been collecting several topics and references for blog posts…some of which will probably just never get written as the timeliness of the topics fade over time.  Nonetheless, I’m back, and I think it is time to revive my Doing Business Right series, this time coming from the slant of managing a development team rather than the previous angle of being self-employed.  First up: separating Dev, Test, and Prod. A few months ago, Colin Stasiuk (@BenchmarkIT) wrote a great post about separating your Dev, Test/UAT, and Prod environments.  This post covers all the important points such as removing Developer access from both PROD and UAT, and the importance of proper deployment (a.k.a. promotion) procedures.  I won’t repeat it all here, go read the original!  But what I do want to address is what I believe to be the #1 excuse people use for not having separate environments:  Money.  I discussed this briefly in my comment on Colin’s post at the time, but let me repeat it here and expand on it a bit. Don’t let the size of your company or the size of its budget dictate whether you do things professionally or not.  I am convinced that most developers and development teams would agree that it is a best practice to have separate environments for development, testing, and production (a.k.a. Live).  So why don’t they?  Because they think that it means separate servers which means more money.  While having separate physical servers for the different environments would be ideal, it is not an absolute requirement in order to make this work.  Here are a few ideas: Use multiple instances of SQL Server and multiple Web Sites with Headers or Ports.  For no additional fees* you can install multiple instances of SQL Server on the same machine.  This gives you a nice separation, allowing you to even use the same database names as will appear in PROD, yet isolating the data and security access.  And in IIS, you can create multiple Web Sites on the same server just by using Host Headers or different port numbers to separate them.  This approach does still pose the risk of non-Prod environments impacting performance on Prod, but when your application is busy enough for that to be a concern, you can probably afford one of the other options. Use desktop PCs instead of servers.  Instead of investing in full server-grade hardware, you can mimic the separate environments on old desktop PCs and at least get functional equivalency, if not performance matching.  The last I checked, Microsoft did not require separate licensing for SQL Server if that installation was used exclusively for dev or test purposes*.  There may be some version or performance differences between this approach and what you have in Prod, but you have isolated test from impacting Prod resources this way. Virtualization.  This is of course one of the hot topics of the day, and I would be remiss if I did not suggest this.  It is quite easy these days to setup virtual machines so that, again, your environments are fairly isolated from one another, and you retain all the security and procedural benefits of having separate environments. So the point is, keep your high professional standards intact.  You don’t need to compromise on using proper procedure just because you work in a small company with a small budget.  Keep doing things the right way! By the way, where I work, our DEV environment is not on a server.  All development is done on the developer’s individual workstation where it can be isolated from other developers’ work for the duration of writing the code, but also where the developers have to reconcile (merge) differences in code under concurrent development.  This usually means that each change is executed multiple times (once per developer to update their environments with the latest changes from others) giving us an extra, informal. test deployment before even going to the Test/UAT server.  It also means that if the network goes down, the developers can continue to hum along because they are not dependent on networked resources.  In fact, they will likely be even more productive because they aren’t being interrupted by email…but that’s another post I need to write. * I am not a lawyer, nor a licensing specialist, but it appeared to be so the last time I checked.  When in doubt, consult an expert on the topic.

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  • Windows Azure Recipe: Enterprise LOBs

    - by Clint Edmonson
    Enterprises are more and more dependent on their specialized internal Line of Business (LOB) applications than ever before. Naturally, the more software they leverage on-premises, the more infrastructure they need manage. It’s frequently the case that our customers simply can’t scale up their hardware purchases and operational staff as fast as internal demand for software requires. The result is that getting new or enhanced applications in the hands of business users becomes slower and more expensive every day. Being able to quickly deliver applications in a rapidly changing business environment while maintaining high standards of corporate security is a challenge that can be met right now by moving enterprise LOBs out into the cloud and leveraging Azure’s Access Control services. In fact, we’re seeing many of our customers (both large and small) see huge benefits from moving their web based business applications such as corporate help desks, expense tracking, travel portals, timesheets, and more to Windows Azure. Drivers Cost Reduction Time to market Security Solution Here’s a sketch of how many Windows Azure Enterprise LOBs are being architected and deployed: Ingredients Web Role – this will host the core of the application. Each web role is a virtual machine hosting an application written in ASP.NET (or optionally php, or node.js). The number of web roles can be scaled up or down as needed to handle peak and non-peak traffic loads. Many Java based applications are also being deployed to Windows Azure with a little more effort. Database – every modern web application needs to store data. SQL Azure databases look and act exactly like their on-premise siblings but are fault tolerant and have data redundancy built in. Access Control – this service is necessary to establish federated identity between the cloud hosted application and an enterprise’s corporate network. It works in conjunction with a secure token service (STS) that is hosted on-premises to establish the corporate user’s identity and credentials. The source code for an on-premises STS is provided in the Windows Azure training kit and merely needs to be customized for the corporate environment and published on a publicly accessible corporate web site. Once set up, corporate users see a near seamless single sign-on experience. Reporting – businesses live and die by their reports and SQL Azure Reporting, based on SQL Server Reporting 2008 R2, can serve up reports with tables, charts, maps, gauges, and more. These reports can be accessed from the Windows Azure Portal, through a web browser, or directly from applications. Service Bus (optional) – if deep integration with other applications and systems is needed, the service bus is the answer. It enables secure service layer communication between applications hosted behind firewalls in on-premises or partner datacenters and applications hosted inside Windows Azure. The Service Bus provides the ability to securely expose just the information and services that are necessary to create a simpler, more secure architecture than opening up a full blown VPN. Data Sync (optional) – in cases where the data stored in the cloud needs to be shared internally, establishing a secure one-way or two-way data-sync connection between the on-premises and off-premises databases is a perfect option. It can be very granular, allowing us to specify exactly what tables and columns to synchronize, setup filters to sync only a subset of rows, set the conflict resolution policy for two-way sync, and specify how frequently data should be synchronized Training Labs These links point to online Windows Azure training labs where you can learn more about the individual ingredients described above. (Note: The entire Windows Azure Training Kit can also be downloaded for offline use.) Windows Azure (16 labs) Windows Azure is an internet-scale cloud computing and services platform hosted in Microsoft data centers, which provides an operating system and a set of developer services which can be used individually or together. It gives developers the choice to build web applications; applications running on connected devices, PCs, or servers; or hybrid solutions offering the best of both worlds. New or enhanced applications can be built using existing skills with the Visual Studio development environment and the .NET Framework. With its standards-based and interoperable approach, the services platform supports multiple internet protocols, including HTTP, REST, SOAP, and plain XML SQL Azure (7 labs) Microsoft SQL Azure delivers on the Microsoft Data Platform vision of extending the SQL Server capabilities to the cloud as web-based services, enabling you to store structured, semi-structured, and unstructured data. Windows Azure Services (9 labs) As applications collaborate across organizational boundaries, ensuring secure transactions across disparate security domains is crucial but difficult to implement. Windows Azure Services provides hosted authentication and access control using powerful, secure, standards-based infrastructure. See my Windows Azure Resource Guide for more guidance on how to get started, including links web portals, training kits, samples, and blogs related to Windows Azure.

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  • Safely deploying changes to production servers

    - by oazabir
    When you deploy incremental changes on a production server, which is running and live all the time, you some times see error messages like “Compiler Error Message: The Type ‘XXX’ exists in both…”. Sometimes you find Application_Start event not firing although you shipped a new class, dll or web.config. Sometimes you find static variables not getting initialized and so on. There are so many weird things happen on webservers when you incrementally deploy changes to the server and the server has been up and running for several weeks. So, I came up with a full proof house keeping steps that we always do whenever we deploy some incremental change to our websites. These steps ensure that the web sites are properly recycled , cached are cleared, all the data stored at Application level is initialized. First of all you should have multiple web servers behind load balancer. This way you can take one server our of the production traffic, do your deployment and house keeping tasks like restarting IIS, and then put it back. Then you can do it for the second server and so on. This ensures there’s no outage for customer. If you can do it reasonable fast, hopefully customers won’t notice discrepancy between the servers some having new code and some having old code. You should only do this when your changes aren’t drastic. For ex, you aren’t delivering a complete revamped UI. In that case, some users hitting server1 with latest UI will suddenly get a completely different experience and then on next page refresh, they might hit server2 with old code and get a totally different experience. This works for incremental non-dramatic changes only.   During deployment you should follow these steps: Take server X out of load balancer so that it does not get any traffic. Stop all windows services on the server. Stop IIS. Delete the Temporary ASP.NET folders of all .NET versions incase you have multiple .NET versions running. You can follow this link. Deploy the changes. Flush any distributed cache you have, for ex, Velocity or Memcached. Start IIS. Start the windows services on the server. Warm up all websites by hitting major URLs on the websites. You should have some automated script to do this. You can use tinyget to hit some major URLs, especially pages that take a lot of time to compile. Read my post on keeping websites warm with zero coding. Put server X back to load balancer so that it starts receiving traffic. That’s it. It should give you a clean deployment and prevent unexpected errors. You should print these steps and hang on the desk of your deployment guys so that they never forget during deployment pressure.

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  • Hype and LINQ

    - by Tony Davis
    "Tired of querying in antiquated SQL?" I blinked in astonishment when I saw this headline on the LinqPad site. Warming to its theme, the site suggests that what we need is to "kiss goodbye to SSMS", and instead use LINQ, a modern query language! Elsewhere, there is an article entitled "Why LINQ beats SQL". The designers of LINQ, along with many DBAs, would, I'm sure, cringe with embarrassment at the suggestion that LINQ and SQL are, in any sense, competitive ways of doing the same thing. In fact what LINQ really is, at last, is an efficient, declarative language for C# and VB programmers to access or manipulate data in objects, local data stores, ORMs, web services, data repositories, and, yes, even relational databases. The fact is that LINQ is essentially declarative programming in a .NET language, and so in many ways encourages developers into a "SQL-like" mindset, even though they are not directly writing SQL. In place of imperative logic and loops, it uses various expressions, operators and declarative logic to build up an "expression tree" describing only what data is required, not the operations to be performed to get it. This expression tree is then parsed by the language compiler, and the result, when used against a relational database, is a SQL string that, while perhaps not always perfect, is often correctly parameterized and certainly no less "optimal" than what is achieved when a developer applies blunt, imperative logic to the SQL language. From a developer standpoint, it is a mistake to consider LINQ simply as a substitute means of querying SQL Server. The strength of LINQ is that that can be used to access any data source, for which a LINQ provider exists. Microsoft supplies built-in providers to access not just SQL Server, but also XML documents, .NET objects, ADO.NET datasets, and Entity Framework elements. LINQ-to-Objects is particularly interesting in that it allows a declarative means to access and manipulate arrays, collections and so on. Furthermore, as Michael Sorens points out in his excellent article on LINQ, there a whole host of third-party LINQ providers, that offers a simple way to get at data in Excel, Google, Flickr and much more, without having to learn a new interface or language. Of course, the need to be generic enough to deal with a range of data sources, from something as mundane as a text file to as esoteric as a relational database, means that LINQ is a compromise and so has inherent limitations. However, it is a powerful and beautifully compact language and one that, at least in its "query syntax" guise, is accessible to developers and DBAs alike. Perhaps there is still hope that LINQ can fulfill Phil Factor's lobster-induced fantasy of a language that will allow us to "treat all data objects, whether Word files, Excel files, XML, relational databases, text files, HTML files, registry files, LDAPs, Outlook and so on, in the same logical way, as linked databases, and extract the metadata, create the entities and relationships in the same way, and use the same SQL syntax to interrogate, create, read, write and update them." Cheers, Tony.

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  • Win32 and Win64 programming in C sources?

    - by Nick Rosencrantz
    I'm learning OpenGL with C and that makes me include the windows.h file in my project. I'd like to look at some more specific windows functions and I wonder if you can cite some good sources for learning the basics of Win32 and Win64 programming in C (or C++). I use MS Visual C++ and I prefer to stick with C even though much of the Windows API seems to be C++. I'd like my program to be portable and using some platform-indepedent graphics library like OpenGL I could make my program portable with some slight changes for window management. Could you direct me with some pointers to books or www links where I can find more info? I've already studied the OpenGL red book and the C programming language, what I'm looking for is the platform-dependent stuff and how to handle that since I run both Linux and Windows where I find the development environment Visual Studio is pretty good but the debugger gdb is not available on windows so it's a trade off which environment i'll choose in the end - Linux with gcc or Windows with MSVC. Here is the program that draws a graphics primitive with some use of windows.h This program is also runnable on Linux without changing the code that actually draws the graphics primitive: #include <windows.h> #include <gl/gl.h> LRESULT CALLBACK WindowProc(HWND, UINT, WPARAM, LPARAM); void EnableOpenGL(HWND hwnd, HDC*, HGLRC*); void DisableOpenGL(HWND, HDC, HGLRC); int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) { WNDCLASSEX wcex; HWND hwnd; HDC hDC; HGLRC hRC; MSG msg; BOOL bQuit = FALSE; float theta = 0.0f; /* register window class */ wcex.cbSize = sizeof(WNDCLASSEX); wcex.style = CS_OWNDC; wcex.lpfnWndProc = WindowProc; wcex.cbClsExtra = 0; wcex.cbWndExtra = 0; wcex.hInstance = hInstance; wcex.hIcon = LoadIcon(NULL, IDI_APPLICATION); wcex.hCursor = LoadCursor(NULL, IDC_ARROW); wcex.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH); wcex.lpszMenuName = NULL; wcex.lpszClassName = "GLSample"; wcex.hIconSm = LoadIcon(NULL, IDI_APPLICATION);; if (!RegisterClassEx(&wcex)) return 0; /* create main window */ hwnd = CreateWindowEx(0, "GLSample", "OpenGL Sample", WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 256, 256, NULL, NULL, hInstance, NULL); ShowWindow(hwnd, nCmdShow); /* enable OpenGL for the window */ EnableOpenGL(hwnd, &hDC, &hRC); /* program main loop */ while (!bQuit) { /* check for messages */ if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)) { /* handle or dispatch messages */ if (msg.message == WM_QUIT) { bQuit = TRUE; } else { TranslateMessage(&msg); DispatchMessage(&msg); } } else { /* OpenGL animation code goes here */ glClearColor(0.0f, 0.0f, 0.0f, 0.0f); glClear(GL_COLOR_BUFFER_BIT); glPushMatrix(); glRotatef(theta, 0.0f, 0.0f, 1.0f); glBegin(GL_TRIANGLES); glColor3f(1.0f, 0.0f, 0.0f); glVertex2f(0.0f, 1.0f); glColor3f(0.0f, 1.0f, 0.0f); glVertex2f(0.87f, -0.5f); glColor3f(0.0f, 0.0f, 1.0f); glVertex2f(-0.87f, -0.5f); glEnd(); glPopMatrix(); SwapBuffers(hDC); theta += 1.0f; Sleep (1); } } /* shutdown OpenGL */ DisableOpenGL(hwnd, hDC, hRC); /* destroy the window explicitly */ DestroyWindow(hwnd); return msg.wParam; } LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam) { switch (uMsg) { case WM_CLOSE: PostQuitMessage(0); break; case WM_DESTROY: return 0; case WM_KEYDOWN: { switch (wParam) { case VK_ESCAPE: PostQuitMessage(0); break; } } break; default: return DefWindowProc(hwnd, uMsg, wParam, lParam); } return 0; } void EnableOpenGL(HWND hwnd, HDC* hDC, HGLRC* hRC) { PIXELFORMATDESCRIPTOR pfd; int iFormat; /* get the device context (DC) */ *hDC = GetDC(hwnd); /* set the pixel format for the DC */ ZeroMemory(&pfd, sizeof(pfd)); pfd.nSize = sizeof(pfd); pfd.nVersion = 1; pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER; pfd.iPixelType = PFD_TYPE_RGBA; pfd.cColorBits = 24; pfd.cDepthBits = 16; pfd.iLayerType = PFD_MAIN_PLANE; iFormat = ChoosePixelFormat(*hDC, &pfd); SetPixelFormat(*hDC, iFormat, &pfd); /* create and enable the render context (RC) */ *hRC = wglCreateContext(*hDC); wglMakeCurrent(*hDC, *hRC); } void DisableOpenGL (HWND hwnd, HDC hDC, HGLRC hRC) { wglMakeCurrent(NULL, NULL); wglDeleteContext(hRC); ReleaseDC(hwnd, hDC); }

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