Search Results

Search found 7418 results on 297 pages for 'argument passing'.

Page 243/297 | < Previous Page | 239 240 241 242 243 244 245 246 247 248 249 250  | Next Page >

• RemoveHandler Issues with Custom Events

  - by Jeff Certain

  This is a case of things being more complicated that I thought they should be. Since it took a while to figure this one out, I thought it was worth explaining and putting all of the pieces to the answer in one spot. Let me set the stage. Architecturally, I have the notion of generic producers and consumers. These put items onto, and remove items from, a queue. This provides a generic, thread-safe mechanism to load balance the creation and processing of work items in our application. Part of the IProducer(Of T) interface is: 1: Public Interface IProducer(Of T) 2: Event ItemProduced(ByVal sender As IProducer(Of T), ByVal item As T) 3: Event ProductionComplete(ByVal sender As IProducer(Of T)) 4: End Interface Nothing sinister there, is there? In order to simplify our developers’ lives, I wrapped the queue with some functionality to manage the produces and consumers. Since the developer can specify the number of producers and consumers that are spun up, the queue code manages adding event handlers as the producers and consumers are instantiated. Now, we’ve been having some memory leaks and, in order to eliminate the possibility that this was caused by weak references to event handles, I wanted to remove them. This is where it got dicey. My first attempt looked like this: 1: For Each producer As P In Producers 2: RemoveHandler producer.ItemProduced, AddressOf ItemProducedHandler 3: RemoveHandler producer.ProductionComplete, AddressOf ProductionCompleteHandler 4: producer.Dispose() 5: Next What you can’t see in my posted code are the warnings this caused. The 'AddressOf' expression has no effect in this context because the method argument to 'AddressOf' requires a relaxed conversion to the delegate type of the event. Assign the 'AddressOf' expression to a variable, and use the variable to add or remove the method as the handler.  Now, what on earth does that mean? Well, a quick Bing search uncovered a whole bunch of talk about delegates. The first solution I found just changed all parameters in the event handler to Object. Sorry, but no. I used generics precisely because I wanted type safety, not because I wanted to use Object. More searching. Eventually, I found this forum post, where Jeff Shan revealed a missing piece of the puzzle. The other revelation came from Lian_ZA in this post. However, these two only hinted at the solution. Trying some of what they suggested led to finally getting an invalid cast exception that revealed the existence of ItemProducedEventHandler. Hold on a minute! I didn’t create that delegate. There’s nothing even close to that name in my code… except the ItemProduced event in the interface. Could it be? Naaaaah. Hmmm…. Well, as it turns out, there is a delegate created by the compiler for each event. By explicitly creating a delegate that refers to the method in question, implicitly cast to the generated delegate type, I was able to remove the handlers: 1: For Each producer As P In Producers 2: Dim _itemProducedHandler As IProducer(Of T).ItemProducedEventHandler = AddressOf ItemProducedHandler 3: RemoveHandler producer.ItemProduced, _itemProducedHandler 4:  5: Dim _productionCompleteHandler As IProducer(Of T).ProductionCompleteEventHandler = AddressOf ProductionCompleteHandler 6: RemoveHandler producer.ProductionComplete, _productionCompleteHandler 7: producer.Dispose() 8: Next That’s “all” it took to finally be able to remove the event handlers and maintain type-safe code. Hopefully, this will save you the same challenges I had in trying to figure out how to fix this issue!

  Read the article

• OpenGL 3 and the Radeon HD 4850x2

  - by rotard

  A while ago, I picked up a copy of the OpenGL SuperBible fifth edition and slowly and painfully started teaching myself OpenGL the 3.3 way, after having been used to the 1.0 way from school way back when. Making things more challenging, I am primarily a .NET developer, so I was working in Mono with the OpenTK OpenGL wrapper. On my laptop, I put together a program that let the user walk around a simple landscape using a couple shaders that implemented per-vertex coloring and lighting and texture mapping. Everything was working brilliantly until I ran the same program on my desktop. Disaster! Nothing would render! I have chopped my program down to the point where the camera sits near the origin, pointing at the origin, and renders a square (technically, a triangle fan). The quad renders perfectly on my laptop, coloring, lighting, texturing and all, but the desktop renders a small distorted non-square quadrilateral that is colored incorrectly, not affected by the lights, and not textured. I suspect the graphics card is at fault, because I get the same result whether I am booted into Ubuntu 10.10 or Win XP. I did find that if I pare the vertex shader down to ONLY outputting the positional data and the fragment shader to ONLY outputting a solid color (white) the quad renders correctly. But as SOON as I start passing in color data (whether or not I use it in the fragment shader) the output from the vertex shader is distorted again. The shaders follow. I left the pre-existing code in, but commented out so you can get an idea what I was trying to do. I'm a noob at glsl so the code could probably be a lot better. My laptop is an old lenovo T61p with a Centrino (Core 2) Duo and an nVidia Quadro graphics card running Ubuntu 10.10 My desktop has an i7 with a Radeon HD 4850 x2 (single card, dual GPU) from Saphire dual booting into Ubuntu 10.10 and Windows XP. The problem occurs in both XP and Ubuntu. Can anyone see something wrong that I am missing? What is "special" about my HD 4850x2? string vertexShaderSource = @" #version 330 precision highp float; uniform mat4 projection_matrix; uniform mat4 modelview_matrix; //uniform mat4 normal_matrix; //uniform mat4 cmv_matrix; //Camera modelview. Light sources are transformed by this matrix. //uniform vec3 ambient_color; //uniform vec3 diffuse_color; //uniform vec3 diffuse_direction; in vec4 in_position; in vec4 in_color; //in vec3 in_normal; //in vec3 in_tex_coords; out vec4 varyingColor; //out vec3 varyingTexCoords; void main(void) { //Get surface normal in eye coordinates //vec4 vEyeNormal = normal_matrix * vec4(in_normal, 0); //Get vertex position in eye coordinates //vec4 vPosition4 = modelview_matrix * vec4(in_position, 0); //vec3 vPosition3 = vPosition4.xyz / vPosition4.w; //Get vector to light source in eye coordinates //vec3 lightVecNormalized = normalize(diffuse_direction); //vec3 vLightDir = normalize((cmv_matrix * vec4(lightVecNormalized, 0)).xyz); //Dot product gives us diffuse intensity //float diff = max(0.0, dot(vEyeNormal.xyz, vLightDir.xyz)); //Multiply intensity by diffuse color, force alpha to 1.0 //varyingColor.xyz = in_color * diff * diffuse_color.xyz; varyingColor = in_color; //varyingTexCoords = in_tex_coords; gl_Position = projection_matrix * modelview_matrix * in_position; }"; string fragmentShaderSource = @" #version 330 //#extension GL_EXT_gpu_shader4 : enable precision highp float; //uniform sampler2DArray colorMap; //in vec4 varyingColor; //in vec3 varyingTexCoords; out vec4 out_frag_color; void main(void) { out_frag_color = vec4(1,1,1,1); //out_frag_color = varyingColor; //out_frag_color = vec4(varyingColor, 1) * texture(colorMap, varyingTexCoords.st); //out_frag_color = vec4(varyingColor, 1) * texture(colorMap, vec3(varyingTexCoords.st, 0)); //out_frag_color = vec4(varyingColor, 1) * texture2DArray(colorMap, varyingTexCoords); }"; Note that in this code the color data is accepted but not actually used. The geometry is outputted the same (wrong) whether the fragment shader uses varyingColor or not. Only if I comment out the line varyingColor = in_color; does the geometry output correctly. Originally the shaders took in vec3 inputs, I only modified them to take vec4s while troubleshooting.

  Read the article

• My 2D collision code does not work as expected. How do I fix it?

  - by farmdve

  I have a simple 2D game with a tile-based map. I am new to game development, I followed the LazyFoo tutorials on SDL. The tiles are in a bmp file, but each tile inside it corresponds to an internal number of the type of tile(color, or wall). The game is simple, but the code is a lot so I can only post snippets. // Player moved out of the map if((player.box.x < 0)) player.box.x += GetVelocity(player, 0); if((player.box.y < 0)) player.box.y += GetVelocity(player, 1); if((player.box.x > (LEVEL_WIDTH - DOT_WIDTH))) player.box.x -= GetVelocity(player, 0); if((player.box.y > (LEVEL_HEIGHT - DOT_HEIGHT))) player.box.y -= GetVelocity(player, 1); // Now that we are here, we check for collisions if(touches_wall(player.box)) { if(player.box.x < player.prev_x) { player.box.x += GetVelocity(player, 0); } if(player.box.x > player.prev_x) { player.box.x -= GetVelocity(player, 0); } if(player.box.y < player.prev_y) { player.box.y += GetVelocity(player, 1); } if(player.box.y > player.prev_y) { player.box.y -= GetVelocity(player, 1); } } player.prev_x = player.box.x; player.prev_y = player.box.y; Let me explain, player is a structure with the following contents typedef struct { Rectangle box; //Player position on a map(tile or whatever). int prev_x, prev_y; // Previous positions int key_press[3]; // Stores which key was pressed/released. Limited to three keys. E.g Left,right and perhaps jump if possible in 2D int velX, velY; // Velocity for X and Y coordinate. //Health int health; bool main_character; uint32_t jump_ticks; } Player; And Rectangle is just a typedef of SDL_Rect. GetVelocity is a function that according to the second argument, returns the velocity for the X or Y axis. This code I have basically works, however inside the if(touches_wall(player.box)) if statement, I have 4 more. These 4 if statements are responsible for detecting collision on all 4 sides(up,down,left,right). However, they also act as a block for any other movement. Example: I move down the object and collide with the wall, as I continue to move down and still collide with the wall, I wish to move left or right, which is indeed possible(not to mention in 3D games), but remember the 4 if statements? They are preventing me from moving anywhere. The original code on the LazyFoo Productions website has no problems, but it was written in C++, so I had to rewrite most of it to work, which is probably where the problem comes from. I also use a different method of moving, than the one in the examples. Of course, that was just an example. I wish to be able to move no matter at which wall I collide. Before this bit of code, I had another one that had more logic in there, but it was flawed.

  Read the article

• "Imprinting" as a language feature?

  - by MKO

  Idea I had this idea for a language feature that I think would be useful, does anyone know of a language that implements something like this? The idea is that besides inheritance a class can also use something called "imprinting" (for lack of better term). A class can imprint one or several (non-abstract) classes. When a class imprints another class it gets all it's properties and all it's methods. It's like the class storing an instance of the imprinted class and redirecting it's methods/properties to it. A class that imprints another class therefore by definition also implements all it's interfaces and it's abstract class. So what's the point? Well, inheritance and polymorphism is hard to get right. Often composition gives far more flexibility. Multiple inheritance offers a slew of different problems without much benefits (IMO). I often write adapter classes (in C#) by implementing some interface and passing along the actual methods/properties to an encapsulated object. The downside to that approach is that if the interface changes the class breaks. You also you have to put in a lot of code that does nothing but pass things along to the encapsulated object. A classic example is that you have some class that implements IEnumerable or IList and contains an internal class it uses. With this technique things would be much easier Example (c#) [imprint List<Person> as peopleList] public class People : PersonBase { public void SomeMethod() { DoSomething(this.Count); //Count is from List } } //Now People can be treated as an List<Person> People people = new People(); foreach(Person person in people) { ... } peopleList is an alias/variablename (of your choice)used internally to alias the instance but can be skipped if not needed. One thing that's useful is to override an imprinted method, that could be achieved with the ordinary override syntax public override void Add(Person person) { DoSomething(); personList.Add(person); } note that the above is functional equivalent (and could be rewritten by the compiler) to: public class People : PersonBase , IList<Person> { private List<Person> personList = new List<Person>(); public override void Add(object obj) { this.personList.Add(obj) } public override int IndexOf(object obj) { return personList.IndexOf(obj) } //etc etc for each signature in the interface } only if IList changes your class will break. IList won't change but an interface that you, someone in your team, or a thirdparty has designed might just change. Also this saves you writing a whole lot of code for some interfaces/abstract classes. Caveats There's a couple of gotchas. First we, syntax must be added to call the imprinted classes's constructors from the imprinting class constructor. Also, what happends if a class imprints two classes which have the same method? In that case the compiler would detect it and force the class to define an override of that method (where you could chose if you wanted to call either imprinted class or both) So what do you think, would it be useful, any caveats? It seems it would be pretty straightforward to implement something like that in the C# language but I might be missing something :) Sidenote - Why is this different from multiple inheritance Ok, so some people have asked about this. Why is this different from multiple inheritance and why not multiple inheritance. In C# methods are either virtual or not. Say that we have ClassB who inherits from ClassA. ClassA has the methods MethodA and MethodB. ClassB overrides MethodA but not MethodB. Now say that MethodB has a call to MethodA. if MethodA is virtual it will call the implementation that ClassB has, if not it will use the base class, ClassA's MethodA and you'll end up wondering why your class doesn't work as it should. By the terminology sofar you might already confused. So what happens if ClassB inherits both from ClassA and another ClassC. I bet both programmers and compilers will be scratching their heads. The benefit of this approach IMO is that the imprinting classes are totally encapsulated and need not be designed with multiple inheritance in mind. You can basically imprint anything.

  Read the article

• Managing Operational Risk of Financial Services Processes – part 2/2

  - by Sanjeev Sharma

  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif"; mso-bidi-font-family:"Times New Roman";} In my earlier blog post, I had described the factors that lead to compliance complexity of financial services processes. In this post, I will outline the business implications of the increasing process compliance complexity and the specific role of BPM in addressing the operational risk reduction objectives of regulatory compliance. First, let’s look at the business implications of increasing complexity of process compliance for financial institutions: · Increased time and cost of compliance due to duplication of effort in conforming to regulatory requirements due to process changes driven by evolving regulatory mandates, shifting business priorities or internal/external audit requirements · Delays in audit reporting due to quality issues in reconciling non-standard process KPIs and integrity concerns arising from the need to rely on multiple data sources for a given process Next, let’s consider some approaches to managing the operational risk of business processes. Financial institutions considering reducing operational risk of their processes, generally speaking, have two choices: · Rip-and-replace existing applications with new off-the shelf applications. · Extend capabilities of existing applications by modeling their data and process interactions, with other applications or user-channels, outside of the application boundary using BPM. The benefit of the first approach is that compliance with new regulatory requirements would be embedded within the boundaries of these applications. However pre-built compliance of any packaged application or custom-built application should not be mistaken as a one-shot fix for future compliance needs. The reason is that business needs and regulatory requirements inevitably out grow end-to-end capabilities of even the most comprehensive packaged or custom-built business application. Thus, processes that originally resided within the application will eventually spill outside the application boundary. It is precisely at such hand-offs between applications or between overlaying processes where vulnerabilities arise to unknown and accidental faults that potentially result in errors and lead to partial or total failure. The gist of the above argument is that processes which reside outside application boundaries, in other words, span multiple applications constitute a latent operational risk that spans the end-to-end value chain. For instance, distortion of data flowing from an account-opening application to a credit-rating system if left un-checked renders compliance with “KYC” policies void even when the “KYC” checklist was enforced at the time of data capture by the account-opening application. Oracle Business Process Management is enabling financial institutions to lower operational risk of such process ”gaps” for Financial Services processes including “Customer On-boarding”, “Quote-to-Contract”, “Deposit/Loan Origination”, “Trade Exceptions”, “Interest Claim Tracking” etc.. If you are faced with a similar challenge and need any guidance on the same feel free to drop me a note.

  Read the article

• ORE graphics using Remote Desktop Protocol

  - by Sherry LaMonica

  Oracle R Enterprise graphics are returned as raster, or bitmap graphics. Raster images consist of tiny squares of color information referred to as pixels that form points of color to create a complete image. Plots that contain raster images render quickly in R and create small, high-quality exported image files in a wide variety of formats. However, it is a known issue that the rendering of raster images can be problematic when creating graphics using a Remote Desktop connection. Raster images do not display in the windows device using Remote Desktop under the default settings. This happens because Remote Desktop restricts the number of colors when connecting to a Windows machine to 16 bits per pixel, and interpolating raster graphics requires many colors, at least 32 bits per pixel.. For example, this simple embedded R image plot will be returned in a raster-based format using a standalone Windows machine:  R> library(ORE) R> ore.connect(user="rquser", sid="orcl", host="localhost", password="rquser", all=TRUE)  R> ore.doEval(function() image(volcano, col=terrain.colors(30))) Here, we first load the ORE packages and connect to the database instance using database login credentials. The ore.doEval function executes the R code within the database embedded R engine and returns the image back to the client R session. Over a Remote Desktop connection under the default settings, this graph will appear blank due to the restricted number of colors. Users who encounter this issue have two options to display ORE graphics over Remote Desktop: either raise Remote Desktop's Color Depth or direct the plot output to an alternate device. Option #1: Raise Remote Desktop Color Depth setting In a Remote Desktop session, all environment variables, including display variables determining Color Depth, are determined by the RCP-Tcp connection settings. For example, users can reduce the Color Depth when connecting over a slow connection. The different settings are 15 bits, 16 bits, 24 bits, or 32 bits per pixel. To raise the Remote Desktop color depth: On the Windows server, launch Remote Desktop Session Host Configuration from the Accessories menu.Under Connections, right click on RDP-Tcp and select Properties.On the Client Settings tab either uncheck LimitMaximum Color Depth or set it to 32 bits per pixel. Click Apply, then OK, log out of the remote session and reconnect.After reconnecting, the Color Depth on the Display tab will be set to 32 bits per pixel.  Raster graphics will now display as expected. For ORE users, the increased color depth results in slightly reduced performance during plot creation, but the graph will be created instead of displaying an empty plot. Option #2: Direct plot output to alternate device Plotting to a non-windows device is a good option if it's not possible to increase Remote Desktop Color Depth, or if performance is degraded when creating the graph. Several device drivers are available for off-screen graphics in R, such as postscript, pdf, and png. On-screen devices include windows, X11 and Cairo. Here we output to the Cairo device to render an on-screen raster graphic.  The grid.raster function in the grid package is analogous to other grid graphical primitives - it draws a raster image within the current plot's grid.  R> options(device = "CairoWin") # use Cairo device for plotting during the session R> library(Cairo) # load Cairo, grid and png libraries  R> library(grid) R> library(png)  R> res <- ore.doEval(function()image(volcano,col=terrain.colors(30))) # create embedded R plot  R> img <- ore.pull(res, graphics = TRUE)$img[[1]] # extract image  R> grid.raster(as.raster(readPNG(img)), interpolate = FALSE) # generate raster graph R> dev.off() # turn off first device   By default, the interpolate argument to grid.raster is TRUE, which means that what is actually drawn by R is a linear interpolation of the pixels in the original image. Setting interpolate to FALSE uses a sample from the pixels in the original image.A list of graphics devices available in R can be found in the Devices help file from the grDevices package: R> help(Devices)

  Read the article

• Clone a VirtualBox Machine

  I just installed VirtualBox, which I want to try out based on recommendations from peers for running a server from within my Windows 7 x64 OS.  Ive never used VirtualBox, so Im certainly no expert at it, but I did want to share my experience with it thus far.  Specifically, my intention is to create a couple of virtual machines.  One I intend to use as a build server, for which a virtual machine makes sense because I can easily move it around as needed if there are hardware issues (its worth noting my need for setting up a build server at the moment is a result of a disk failure on the old build server).  The other VM I want to set up will act as a proxy server for the issue tracking system were using at Code Project, Axosoft OnTime.  They have a Remote Server application for this purpose, and since the OnTime install is 300 miles away from my location, the Remote Server should speed up my use of the OnTime client by limiting the chattiness with the database (at least, thats the hope). So, I need two VMs, and Im lazy.  I dont want to have to install the OS and such twice.  No problem, it should be simple to clone a virtualbox machine, or clone a virtualbox hard drive, right?  Well unfortunately, if you look at the UI for VirtualBox, theres no such command.  Youre left wondering How do I clone a VirtualBox machine? or the slightly related How do I clone a VirtualBox hard drive? If youve used VirtualPC, then you know that its actually pretty easy to copy and move around those VMs.  Not quite so easy with VirtualBox.  Finding the files is easy, theyre located in your user folder within the .VirtualBox folder (possibly within a HardDisks folder).  The disks have a .vdi extension and will be pretty large if youve installed anything.  The one shown here has just Windows Server 2008 R2 installed on it nothing else. If you copy the .vdi file and rename it, you can use the Virtual Media Manager to view it and you can create a new machine and choose the new drive to attach to.  Unfortunately, if you simply make a copy of the drive, this wont work and youll get an error that says something to the effect of: Cannot register the hard disk PATH with UUID {id goes here} because a hard disk PATH2 with UUID {same id goes here} already exists in the media registry (PATH to XML file). There are command line tools you can use to do this in a way that avoids this error.  Specifically, the c:\Program File\Sun\VirtualBox\VBoxManage.exe program is used for all command line access to VirtualBox, and to copy a virtual disk (.vdi file) you would call something like this: VBoxManage clonehd Disk1.vdi Disk1_Copy.vdi However, in my case this didnt work.  I got basically the same error I showed above, along with some debug information for line 628 of VBoxManageDisk.cpp.  As my main task was not to debug the C++ code used to write VirtualBox, I continued looking for a simple way to clone a virtual drive.  I found it in this blog post. The Secret setvdiuuid Command VBoxManage has a whole bunch of commands you can use with it just pass it /? to see the list.  However, it also has a special command called internalcommands that opens up access to even more commands.  The one thats interesting for us here is the setvdiuuid command.  By calling this command and passing in the file path to your vdi file, it will reset the UUID to a new (random, apparently) UUID.  This then allows the virtual media manager to cope with the file, and lets you set up new machines that reference the newly UUIDd virtual drive.  The full command line would be: VBoxManage internalcommands setvdiuuid MyCopy.vdi The following screenshot shows the error when trying clonehd as well as the successful use of setvdiuuid. Summary Now that I can clone machines easily, its a simple matter to set up base builds of any OS I might need, and then fork from there as needed.  Hopefully the GUI for VirtualBox will be improved to include better support for copying machines/disks, as this is Im sure a very common scenario. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

  Read the article

• Summit reflections

  - by Rob Farley

  So far, my three PASS Summit experiences have been notably different to each other. My first, I wasn’t on the board and I gave two regular sessions and a Lightning Talk in which I told jokes. My second, I was a board advisor, and I delivered a precon, a spotlight and a Lightning Talk in which I sang. My third (last week), I was a full board director, and I didn’t present at all. Let’s not talk about next year. I’m not sure there are many options left. This year, I noticed that a lot more people recognised me and said hello. I guess that’s potentially because of the singing last year, but could also be because board elections can bring a fair bit of attention, and because of the effort I’ve put in through things like 24HOP... Yeah, ok. It’d be the singing. My approach was very different though. I was watching things through different eyes. I looked for the things that seemed to be working and the things that didn’t. I had staff there again, and was curious to know how their things were working out. I knew a lot more about what was going on behind the scenes to make various things happen, and although very little about the Summit was actually my responsibility (based on not having that portfolio), my perspective had moved considerably. Before the Summit started, Board Members had been given notebooks – an idea Tom (who heads up PASS’ marketing) had come up with after being inspired by seeing Bill walk around with a notebook. The plan was to take notes about feedback we got from people. It was a good thing, and the notebook forms a nice pair with the SQLBits one I got a couple of years ago when I last spoke there. I think one of the biggest impacts of this was that during the first keynote, Bill told everyone present about the notebooks. This set a tone of “we’re listening”, and a number of people were definitely keen to tell us things that would cause us to pull out our notebooks. PASSTV was a new thing this year. Justin, the host, featured on the couch and talked a lot of people about a lot of things, including me (he talked to me about a lot of things, I don’t think he talked to a lot people about me). Reaching people through online methods is something which interests me a lot – it has huge potential, and I love the idea of being able to broadcast to people who are unable to attend in person. I’m keen to see how this medium can be developed over time. People who know me will know that I’m a keen advocate of certification – I've been SQL certified since version 6.5, and have even been involved in creating exams. However, I don’t believe in studying for exams. I think training is worthwhile for learning new skills, but the goal should be on learning those skills, not on passing an exam. Exams should be for proving that the skills are there, not a goal in themselves. The PASS Summit is an excellent place to take exams though, and with an attitude of professional development throughout the event, why not? So I did. I wasn’t expecting to take one, but I was persuaded and took the MCM Knowledge Exam. I hadn’t even looked at the syllabus, but tried it anyway. I was very tired, and even fell asleep at one point during it. I’ll find out my result at some point in the future – the Prometric site just says “Tested” at the moment. As I said, it wasn’t something I was expecting to do, but it was good to have something unexpected during the week. Of course it was good to catch up with old friends and make new ones. I feel like every time I’m in the US I see things develop a bit more, with more and more people knowing who I am, who my staff are, and recognising the LobsterPot brand. I missed being a presenter, but I definitely enjoyed seeing many friends on the list of presenters. I won’t try to list them, because there are so many these days that people might feel sad if I don’t mention them. For those that I managed to see, I was pleased to see that the majority of them have lifted their presentation skills since I last saw them, and I happily told them as much. One person who I will mention was Paul White, who travelled from New Zealand to his first PASS Summit. He gave two sessions (a regular session and a half-day), packed large rooms of people, and had everyone buzzing with enthusiasm. I spoke to him after the event, and he told me that his expectations were blown away. Paul isn’t normally a fan of crowds, and the thought of 4000 people would have been scary. But he told me he had no idea that people would welcome him so well, be so friendly and so down to earth. He’s seen the significance of the SQL Server community, and says he’ll be back. It’ll be good to see him there. Will you be there too?

  Read the article

• Missing Fields and Default Values

  - by PointsToShare

  © 2011 By: Dov Trietsch. All rights reserved Dealing with Missing Fields and Default Values New fields and new default values are not propagated throughout the list. They only apply to new and updated items and not to items already entered. They are only prospective. We need to be able to deal with this issue. Here is a scenario. The user has an old list with old items and adds a new field. The field is not created for any of the old items. Trying to get its value raises an Argument Exception. Here is another: a default value is added to a field. All the old items, where the field was not assigned a value, do not get the new default value. The two can also happen in tandem – a new field is added with a default. The older items have neither. Even better, if the user changes the default value, the old items still carry the old defaults. Let’s go a bit further. You have already written code for the list, be it an event receiver, a feature receiver, a console app or a command extension, in which you span all the fields and run on selected items – some new (no problem) and some old (problems aplenty). Had you written defensive code, you would be able to handle the situation, including similar changes in the future. So, without further ado, here’s how. Instead of just getting the value of a field in an item – item[field].ToString() – use the function below. I use ItemValue(item, fieldname, “mud in your eye”) and if “mud in your eye” is what I get, I know that the item did not have the field.   /// <summary> /// Return the column value or a default value /// </summary> private static string ItemValue(SPItem item, string column, string defaultValue) {     try     {         return item[column].ToString();     }     catch (NullReferenceException ex)     {         return defaultValue;     }     catch (ArgumentException ex)     {         return defaultValue;     } } I also use a similar function to return the default and a funny default-default to ascertain that the default does not exist. Here it is:  /// <summary> /// return a fields default or the "default" default. /// </summary> public static string GetFieldDefault(SPField fld, string defValue) {     try     {         // -- Check if default exists.         return fld.DefaultValue.ToString();     }     catch (NullReferenceException ex)     {         return defValue;     }     catch (ArgumentException ex)     {         return defValue;     } } How is this defensive? You have trapped an expected error and dealt with it. Therefore the program did not stop cold in its track and the required code ran to its end. Now, take a further step - write to a log (See Logging – a log blog). Read your own log every now and then, and act accordingly. That’s all Folks!

  Read the article

• Separating text strings into a table of individual words in SQL via XML.

  - by Phil Factor

  p.MsoNormal {margin-top:0cm; margin-right:0cm; margin-bottom:10.0pt; margin-left:0cm; line-height:115%; font-size:11.0pt; font-family:"Calibri","sans-serif"; } Nearly nine years ago, Mike Rorke of the SQL Server 2005 XML team blogged ‘Querying Over Constructed XML Using Sub-queries’. I remember reading it at the time without being able to think of a use for what he was demonstrating. Just a few weeks ago, whilst preparing my article on searching strings, I got out my trusty function for splitting strings into words and something reminded me of the old blog. I’d been trying to think of a way of using XML to split strings reliably into words. The routine I devised turned out to be slightly slower than the iterative word chop I’ve always used in the past, so I didn’t publish it. It was then I suddenly remembered the old routine. Here is my version of it. I’ve unwrapped it from its obvious home in a function or procedure just so it is easy to appreciate. What it does is to chop a text string into individual words using XQuery and the good old nodes() method. I’ve benchmarked it and it is quicker than any of the SQL ways of doing it that I know about. Obviously, you can’t use the trick I described here to do it, because it is awkward to use REPLACE() on 1…n characters of whitespace. I’ll carry on using my iterative function since it is able to tell me the location of each word as a character-offset from the start, and also because this method leaves punctuation in (removing it takes time!). However, I can see other uses for this in passing lists as input or output parameters, or as return values.   if exists (Select * from sys.xml_schema_collections where name like 'WordList')   drop XML SCHEMA COLLECTION WordList go create xml schema collection WordList as ' <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xs:element name="words">        <xs:simpleType>               <xs:list itemType="xs:string" />        </xs:simpleType> </xs:element> </xs:schema>'   go   DECLARE @string VARCHAR(MAX) –we'll get some sample data from the great Ogden Nash Select @String='This is a song to celebrate banks, Because they are full of money and you go into them and all you hear is clinks and clanks, Or maybe a sound like the wind in the trees on the hills, Which is the rustling of the thousand dollar bills. Most bankers dwell in marble halls, Which they get to dwell in because they encourage deposits and discourage withdrawals, And particularly because they all observe one rule which woe betides the banker who fails to heed it, Which is you must never lend any money to anybody unless they don''t need it. I know you, you cautious conservative banks! If people are worried about their rent it is your duty to deny them the loan of one nickel, yes, even one copper engraving of the martyred son of the late Nancy Hanks; Yes, if they request fifty dollars to pay for a baby you must look at them like Tarzan looking at an uppity ape in the jungle, And tell them what do they think a bank is, anyhow, they had better go get the money from their wife''s aunt or ungle. But suppose people come in and they have a million and they want another million to pile on top of it, Why, you brim with the milk of human kindness and you urge them to accept every drop of it, And you lend them the million so then they have two million and this gives them the idea that they would be better off with four, So they already have two million as security so you have no hesitation in lending them two more, And all the vice-presidents nod their heads in rhythm, And the only question asked is do the borrowers want the money sent or do they want to take it withm. Because I think they deserve our appreciation and thanks, the jackasses who go around saying that health and happi- ness are everything and money isn''t essential, Because as soon as they have to borrow some unimportant money to maintain their health and happiness they starve to death so they can''t go around any more sneering at good old money, which is nothing short of providential. '   –we now turn it into XML declare @xml_data xml(WordList)  set @xml_data='<words>'+ replace(@string,'&', '&amp;')+'</words>'    select T.ref.value('.', 'nvarchar(100)')  from (Select @xml_data.query('                      for $i in data(/words) return                      element li { $i }               '))  A(list) cross apply A.List.nodes('/li') T(ref)     …which gives (truncated, of course)…

  Read the article

• Move over DFS and Robocopy, here is SyncToy!

  - by andywe

  Ever since Windows 2000, I have always had the need to replicate data to multiple endpoints with the same content. Until DFS was introduced, the method of thinking was to either manually copy the data location by location, or to batch script it with xcopy and schedule a task. Even though this worked (and still does today), it was cumbersome, and intensive on the network, especially when dealing with larger amounts of data. Then along came robocopy, as an internal tool written by an enterprising programmer at Microsoft. We used it quite a bit, especially when we could not use DFS in the early days. It was received so well, it made it into the public realm. At least now we could have the ability to determine what files had changed and only replicate those. Well, over time there has been evolution of this ideal. DFS is obviously the Windows enterprise class service to do this, along with BrancheCache..however you don’t always need or want the power of DFS, especially when it comes to small datacenter installations, or remote offices. I have specific data sets that are on closed or restricted networks, that either have a security need for this, or are in remote countries where bandwidth is a premium. FOr this, I use the latest evolution for one off replication names Synctoy. Synctoy is from Microsoft, seemingly released in 2009, that wraps a nice GUI around setting up a paired set of folders (remember the mobile briefcase from Windows 98?), and allowing you the choice of synchronization methods. 1 way, or 2 way. Simply create a paired set of folders on the source and destination, choose your options for content, exclude any file types you don’t want to replicate, and click run. Scheduling is even easier. MS has included a wrapper for doing just this so all you enter in your task schedule in the SynToyCMD.exe, a –R as an argument, and the time schedule. No more complicated command lines or scripts.   I find this especially useful when I use MS backup to back up a system volume, but only want subsets of backup information of a data share and ONLY when that dataset has changed. Not relying on full backups and incremental. An example of this is my application installation master share. I back this up with SyncToy because I do not need multiple backup copies..one copy elsewhere suffices to back it up. At home, very useful for your pictures, videos, music, ect..the backup is online and ready to access, not waiting for you to restore a backup file, and no need to institute a domain simply to have DFS.'   Do note there is a risk..if you accidently delete a file and do not catch this before the next sync, then depending on your SyncToy settings, you can indeed lose that file as the destination updates..so due diligence applies. I make it a rule to sync manly one way…I use my master share for making changes, and allow the schedule to follow suit. Any real important file I lock down as read only through file permissions so it cannot be deleted unless I intervene.   Check out the tool and have some fun! http://www.microsoft.com/en-us/download/details.aspx?DisplayLang=en&id=15155

  Read the article

• We have our standards, and we need them

  - by Tony Davis

  The presenter suddenly broke off. He was midway through his section on how to apply to the relational database the Continuous Delivery techniques that allowed for rapid-fire rounds of development and refactoring, while always retaining a “production-ready” state. He sighed deeply and then launched into an astonishing diatribe against Database Administrators, much of his frustration directed toward Oracle DBAs, in particular. In broad strokes, he painted the picture of a brave new deployment philosophy being frustratingly shackled by the relational database, and by especially by the attitudes of the guardians of these databases. DBAs, he said, shunned change and “still favored tools I’d have been embarrassed to use in the ’80′s“. DBAs, Oracle DBAs especially, were more attached to their vendor than to their employer, since the former was the primary source of their career longevity and spectacular remuneration. He contended that someone could produce the best IDE or tool in the world for Oracle DBAs and yet none of them would give a stuff, unless it happened to come from the “mother ship”. I sat blinking in astonishment at the speaker’s vehemence, and glanced around nervously. Nobody in the audience disagreed, and a few nodded in assent. Although the primary target of the outburst was the Oracle DBA, it made me wonder. Are we who work with SQL Server, database professionals or merely SQL Server fanbois? Do DBAs, in general, have an image problem? Is it a good career-move to be seen to be holding onto a particular product by the whites of our knuckles, to the exclusion of all else? If we seek a broad, open-minded, knowledge of our chosen technology, the database, and are blessed with merely mortal powers of learning, then we like standards. Vendors of RDBMSs generally don’t conform to standards by instinct, but by customer demand. Microsoft has made great strides to adopt the international SQL Standards, where possible, thanks to considerable lobbying by the community. The implementation of Window functions is a great example. There is still work to do, though. SQL Server, for example, has an unusable version of the Information Schema. One cast-iron rule of any RDBMS is that we must be able to query the metadata using the same language that we use to query the data, i.e. SQL, and we do this by running queries against the INFORMATION_SCHEMA views. Developers who’ve attempted to apply a standard query that works on MySQL, or some other database, but doesn’t produce the expected results on SQL Server are advised to shun the Standards-based approach in favor of the vendor-specific one, using the catalog views. The argument behind this is sound and well-documented, and of course we all use those catalog views, out of necessity. And yet, as database professionals, committed to supporting the best databases for the business, whatever they are now and in the future, surely our heart should sink somewhat when we advocate a vendor specific approach, to a developer struggling with something as simple as writing a guard clause. And when we read messages on the Microsoft documentation informing us that we shouldn’t rely on INFORMATION_SCHEMA to identify reliably the schema of an object, in SQL Server!

  Read the article

• Contricted A* problem

  - by Ragekit

  I've got a little problem with an A* algorithm that I need to constrict a little bit. Basically : I use an A* to find the shortest path between 2 randomly placed room in 3D space, and then build a corridor between them. The problem I found is that sometimes it makes chimney like corridors that are not ideal, so I constrict the A* so that if the last movement was up or down, you go sideways. Everything is fine, but in some corner cases, it fails to find a path (when there is obviously one). Like here between the blue and red dot : (i'm in unity btw, but i don't think it matters) Here is the code of the actual A* (a bit long, and some redundency) while(current != goal) { //add stair up / stair down foreach(Node<GridUnit> test in current.Neighbors) { if(!test.Data.empty && test != goal) continue; //bug at arrival; if(test == goal && penul !=null) { Vector3 currentDiff = current.Data.bounds.center - test.Data.bounds.center; if(!Mathf.Approximately(currentDiff.y,0)) { //wanna drop on the last if(!coplanar(test.Data.bounds.center,current.Data.bounds.center,current.Data.parentUnit.bounds.center,to.Data.bounds.center)) { continue; } else { if(Mathf.Approximately(to.Data.bounds.center.x, current.Data.parentUnit.bounds.center.x) && Mathf.Approximately(to.Data.bounds.center.z, current.Data.parentUnit.bounds.center.z)) { continue; } } } } if(current.Data.parentUnit != null) { Vector3 previousDiff = current.Data.parentUnit.bounds.center - current.Data.bounds.center; Vector3 currentDiff = current.Data.bounds.center - test.Data.bounds.center; if(!Mathf.Approximately(previousDiff.y,0)) { if(!Mathf.Approximately(currentDiff.y,0)) { //you wanna drop now : continue; } if(current.Data.parentUnit.parentUnit != null) { if(!coplanar(test.Data.bounds.center,current.Data.bounds.center,current.Data.parentUnit.bounds.center,current.Data.parentUnit.parentUnit.bounds.center)) { continue; }else { if(Mathf.Approximately(test.Data.bounds.center.x, current.Data.parentUnit.parentUnit.bounds.center.x) && Mathf.Approximately(test.Data.bounds.center.z, current.Data.parentUnit.parentUnit.bounds.center.z)) { continue; } } } } } g = current.Data.g + HEURISTIC(current.Data,test.Data); h = HEURISTIC(test.Data,goal.Data); f = g + h; if(open.Contains(test) || closed.Contains(test)) { if(test.Data.f > f) { //found a shorter path going passing through that point test.Data.f = f; test.Data.g = g; test.Data.h = h; test.Data.parentUnit = current.Data; } } else { //jamais rencontré test.Data.f = f; test.Data.h = h; test.Data.g = g; test.Data.parentUnit = current.Data; open.Add(test); } } closed.Add (current); if(open.Count == 0) { Debug.Log("nothingfound"); //nothing more to test no path found, stay to from; List<GridUnit> r = new List<GridUnit>(); r.Add(from.Data); return r; } //sort open from small to biggest travel cost open.Sort(delegate(Node<GridUnit> x, Node<GridUnit> y) { return (int)(x.Data.f-y.Data.f); }); //get the smallest travel cost node; Node<GridUnit> smallest = open[0]; current = smallest; open.RemoveAt(0); } //build the path going backward; List<GridUnit> ret = new List<GridUnit>(); if(penul != null) { ret.Insert(0,to.Data); } GridUnit cur = goal.Data; ret.Insert(0,cur); do{ cur = cur.parentUnit; ret.Insert(0,cur); } while(cur != from.Data); return ret; You see at the start of the foreach i constrict the A* like i said. If you have any insight it would be cool. Thanks

  Read the article

• Planning development when academic research is involved

  - by Another Anonymous User

  Dear fellow programmers, how do you do "software planning" when academic research is involved? And, on a side note, how do you convince your boss that writing software is not like building a house and it's more like writing a novel? The gory details are below. I am in charge of a small dev team working in a research lab. We started developing a software with the purpose of going public one day (i.e. sell and make money off that). Such software depends on, amongst other things, at least two independent research lines: that is, there are at least two Ph.D. candidates that will, hopefully, one day come out with a working implementation of what we need. The main software depends also on other, more concrete resources that we as developers can take care of: graphics rendering, soft bodies deformation, etc. My boss asked me to write the specifications, requirements AND a bloody GANTT chart of the entire project. Faced with the fact that I don't have a clue about the research part, and that such research is fundamental for the software, he said "make assumptions." For the clarity of the argument, he is a professor whose Ph.D. students should come up with the research we need. And he comes from a strictly engineering background: plan everything first, write down specifications and only then write down code that "it's the last part". What I am doing now: I broke down the product in features; each 'feature' is, de facto, a separate product; Each feature is built on top of the previous one; Once a feature (A) has a working prototype the team can start working on the next feature (B), while QA for is being done for A (if money allows, more people can be brought in, etc.); Features that depend on research will come last: by then, hopefully, the research part will be completed (when is still a big question) ; Also, I set the team to use SCRUM for the development of 'version 1.0', due in a few months. This deadline could be set based on reasonable assumptions: we listed all required features, we counted our availability, and we gave a reasonable estimate. So my questions, again, are: How do I make my boss happy while at the same time get something out the door? How do I write specifications for something we -the developers- have no clue whether it's possible to do or not? (We still haven't decided which libraries to use for some tasks; we'll do so when we'll need to) How do I get the requirements for that, given that there are yet no clients nor investors, just lots of interests and promises? How do I get peace in the world? I am sure at least one of my questions will be answered :) ps: I am writing this anonymously since a potential investor might backfire if this is discovered. Hope you'll understand. However I must say I do not like this mentality of 'hiding the truth': this program will likely benefit many, and not being able to talk openly about this (with my name and my reputation attached) feels like censorship. But alas, I care more about your suggestions now.

  Read the article

• Some PowerShell goodness

  - by KyleBurns

  Ever work somewhere where processes dump files into folders to maintain an archive?  Me too and Windows Explorer hates it.  Very often I find myself needing to organize these files into subfolders so that I can go after files without locking up Windows Explorer and my answer used to be to write a program in something like C# to do the job.  These programs will typically enumerate the files in a folder and move each file to a subdirectory named based on a datestamp.  The last such program I wrote had to use lower-level Win32 API calls to perform the enumeration because it appears the standard .Net calls make use of the same method of enumerating the directories that Windows Explorer chokes on when dealing with a large number of entries in a particular directory, so a simple task was accomplished with a lot of code. Of course, this little utility was just something I used to make my life easier and "not a production app", so it was in my local source folder and not source control when my hard drive died.  So... I was getting ready to re-create it and thought it might be a good idea to play with PowerShell a bit - something I had been wanting to do but had not yet met a requirement to make me do it.  The resulting script was amazingly succinct and even building the flexibility for parameterization and adding line breaks for readability was only about 25 lines long.  Here's the code with discussion following: param(     [Parameter(         Mandatory = $false,         Position = 0,         HelpMessage = "Root of the folders or share to archive.  Be sure to end with appropriate path separator"     )]     [String] $folderRoot="\\fileServer\pathToFolderWithLotsOfFiles\",       [Parameter(         Mandatory = $false,         Position = 1     )]     [int] $days = 1 ) dir $folderRoot|?{(!($_.PsIsContainer)) -and ((get-date) - $_.lastwritetime).totaldays -gt $days }|%{     [string]$year=$([string]$_.lastwritetime.year)     [string]$month=$_.lastwritetime.month     [string]$day=$_.lastwritetime.day     $dir=$folderRoot+$year+"\"+$month+"\"+$day     if(!(test-path $dir)){         new-item -type container $dir     }     Write-output $_     move-item $_.fullname $dir } The script starts by declaring two parameters.  The first parameter holds the path to the folder that I am going to be sorting into subdirectories.  The path separator is intended to be included in this argument because I didn't want to mess with determining whether this was local or UNC and picking the right separator in code, but this could be easily improved upon using Path.Combine since PowerShell has access to the full framework libraries.  The second parameter holds a minimum age in days for files to be removed from the root folder.  The script then pipes the dir command through a query to include only files (by excluding containers) and of those, only entries that meet the age requirement based on the last modified datestamp.  For each of those, the datestamp is used to construct a folder name in the format YYYY\MM\DD (if you're in an environment where even a day's worth of files need further divided, you could make this more granular) and the folder is created if it does not yet exist.  Finally, the file is moved into the directory. One of the things that was really cool about using PowerShell for this task is that the new-item command is smart enough to create the entire subdirectory structure with a single call.  In previous code that I have written to do this kind of thing, I would have to test the entire tree leading down to the subfolder I want, leading to a lot of branching code that detracted from being able to quickly look at the code and understand the job it performs. Overall, I have to say I'm really pleased with what has been done making PowerShell powerful and useful.

  Read the article

• Data breakpoints to find points where data gets broken

  - by raccoon_tim

  When working with a large code base, finding reasons for bizarre bugs can often be like finding a needle in a hay stack. Finding out why an object gets corrupted without no apparent reason can be quite daunting, especially when it seems to happen randomly and totally out of context. Scenario Take the following scenario as an example. You have defined the a class that contains an array of characters that is 256 characters long. You now implement a method for filling this buffer with a string passed as an argument. At this point you mistakenly expect the buffer to be 256 characters long. At some point you notice that you require another character buffer and you add that after the previous one in the class definition. You now figure that you don’t need the 256 characters that the first member can hold and you shorten that to 128 to conserve space. At this point you should start thinking that you also have to modify the method defined above to safeguard against buffer overflow. It so happens, however, that in this not so perfect world this does not cross your mind. Buffer overflow is one of the most frequent sources for errors in a piece of software and often one of the most difficult ones to detect, especially when data is read from an outside source. Many mass copy functions provided by the C run-time provide versions that have boundary checking (defined with the _s suffix) but they can not guard against hard coded buffer lengths that at some point get changed. Finding the bug Getting back to the scenario, you’re now wondering why does the second string get modified with data that makes no sense at all. Luckily, Visual Studio provides you with a tool to help you with finding just these kinds of errors. It’s called data breakpoints. To add a data breakpoint, you first run your application in debug mode or attach to it in the usual way, and then go to Debug, select New Breakpoint and New Data Breakpoint. In the popup that opens, you can type in the memory address and the amount of bytes you wish to monitor. You can also use an expression here, but it’s often difficult to come up with an expression for data in an object allocated on the heap when not in the context of a certain stack frame. There are a couple of things to note about data breakpoints, however. First of all, Visual Studio supports a maximum of four data breakpoints at any given time. Another important thing to notice is that some C run-time functions modify memory in kernel space which does not trigger the data breakpoint. For instance, calling ReadFile on a buffer that is monitored by a data breakpoint will not trigger the breakpoint. The application will now break at the address you specified it to. Often you might immediately spot the issue but the very least this feature can do is point you in the right direction in search for the real reason why the memory gets inadvertently modified. Conclusions Data breakpoints are a great feature, especially when doing a lot of low level operations where multiple locations modify the same data. With the exception of some special cases, like kernel memory modification, you can use it whenever you need to check when memory at a certain location gets changed on purpose or inadvertently.

  Read the article

• Why is x=x++ undefined?

  - by ugoren

  It's undefined because the it modifies x twice between sequence points. The standard says it's undefined, therefore it's undefined. That much I know. But why? My understanding is that forbidding this allows compilers to optimize better. This could have made sense when C was invented, but now seems like a weak argument. If we were to reinvent C today, would we do it this way, or can it be done better? Or maybe there's a deeper problem, that makes it hard to define consistent rules for such expressions, so it's best to forbid them? So suppose we were to reinvent C today. I'd like to suggest simple rules for expressions such as x=x++, which seem to me to work better than the existing rules. I'd like to get your opinion on the suggested rules compared to the existing ones, or other suggestions. Suggested Rules: Between sequence points, order of evaluation is unspecified. Side effects take place immediately. There's no undefined behavior involved. Expressions evaluate to this value or that, but surely won't format your hard disk (strangely, I've never seen an implementation where x=x++ formats the hard disk). Example Expressions x=x++ - Well defined, doesn't change x. First, x is incremented (immediately when x++ is evaluated), then it's old value is stored in x. x++ + ++x - Increments x twice, evaluates to 2*x+2. Though either side may be evaluated first, the result is either x + (x+2) (left side first) or (x+1) + (x+1) (right side first). x = x + (x=3) - Unspecified, x set to either x+3 or 6. If the right side is evaluated first, it's x+3. It's also possible that x=3 is evaluated first, so it's 3+3. In either case, the x=3 assignment happens immediately when x=3 is evaluated, so the value stored is overwritten by the other assignment. x+=(x=3) - Well defined, sets x to 6. You could argue that this is just shorthand for the expression above. But I'd say that += must be executed after x=3, and not in two parts (read x, evaluate x=3, add and store new value). What's the Advantage? Some comments raised this good point. It's not that I'm after the pleasure of using x=x++ in my code. It's a strange and misleading expression. What I want is to be able to understand complicated expressions. Normally, a complicated expression is no more than the sum of its parts. If you understand the parts and the operators combining them, you can understand the whole. C's current behavior seems to deviate from this principle. One assignment plus another assignment suddenly doesn't make two assignments. Today, when I look at x=x++, I can't say what it does. With my suggested rules, I can, by simply examining its components and their relations.

  Read the article

• Is this over-abstraction? (And is there a name for it?)

  - by mwhite

  I work on a large Django application that uses CouchDB as a database and couchdbkit for mapping CouchDB documents to objects in Python, similar to Django's default ORM. It has dozens of model classes and a hundred or two CouchDB views. The application allows users to register a "domain", which gives them a unique URL containing the domain name that gives them access to a project whose data has no overlap with the data of other domains. Each document that is part of a domain has its domain property set to that domain's name. As far as relationships between the documents go, all domains are effectively mutually exclusive subsets of the data, except for a few edge cases (some users can be members of more than one domain, and there are some administrative reports that include all domains, etc.). The code is full of explicit references to the domain name, and I'm wondering if it would be worth the added complexity to abstract this out. I'd also like to know if there's a name for the sort of bound property approach I'm taking here. Basically, I have something like this in mind: Before in models.py class User(Document): domain = StringProperty() class Group(Document): domain = StringProperty() name = StringProperty() user_ids = StringListProperty() # method that returns related document set def users(self): return [User.get(id) for id in self.user_ids] # method that queries a couch view optimized for a specific lookup @classmethod def by_name(cls, domain, name): # the view method is provided by couchdbkit and handles # wrapping json CouchDB results as Python objects, and # can take various parameters modifying behavior return cls.view('groups/by_name', key=[domain, name]) # method that creates a related document def get_new_user(self): user = User(domain=self.domain) user.save() self.user_ids.append(user._id) return user in views.py: from models import User, Group # there are tons of views like this, (request, domain, ...) def create_new_user_in_group(request, domain, group_name): group = Group.by_name(domain, group_name)[0] user = User(domain=domain) user.save() group.user_ids.append(user._id) group.save() in group/by_name/map.js: function (doc) { if (doc.doc_type == "Group") { emit([doc.domain, doc.name], null); } } After models.py class DomainDocument(Document): domain = StringProperty() @classmethod def domain_view(cls, *args, **kwargs): kwargs['key'] = [cls.domain.default] + kwargs['key'] return super(DomainDocument, cls).view(*args, **kwargs) @classmethod def get(cls, *args, **kwargs, validate_domain=True): ret = super(DomainDocument, cls).get(*args, **kwargs) if validate_domain and ret.domain != cls.domain.default: raise Exception() return ret def models(self): # a mapping of all models in the application. accessing one returns the equivalent of class BoundUser(User): domain = StringProperty(default=self.domain) class User(DomainDocument): pass class Group(DomainDocument): name = StringProperty() user_ids = StringListProperty() def users(self): return [self.models.User.get(id) for id in self.user_ids] @classmethod def by_name(cls, name): return cls.domain_view('groups/by_name', key=[name]) def get_new_user(self): user = self.models.User() user.save() views.py @domain_view # decorator that sets request.models to the same sort of object that is returned by DomainDocument.models and removes the domain argument from the URL router def create_new_user_in_group(request, group_name): group = request.models.Group.by_name(group_name) user = request.models.User() user.save() group.user_ids.append(user._id) group.save() (Might be better to leave the abstraction leaky here in order to avoid having to deal with a couchapp-style //! include of a wrapper for emit that prepends doc.domain to the key or some other similar solution.) function (doc) { if (doc.doc_type == "Group") { emit([doc.name], null); } } Pros and Cons So what are the pros and cons of this? Pros: DRYer prevents you from creating related documents but forgetting to set the domain. prevents you from accidentally writing a django view - couch view execution path that leads to a security breach doesn't prevent you from accessing underlying self.domain and normal Document.view() method potentially gets rid of the need for a lot of sanity checks verifying whether two documents whose domains we expect to be equal are. Cons: adds some complexity hides what's really happening requires no model modules to have classes with the same name, or you would need to add sub-attributes to self.models for modules. However, requiring project-wide unique class names for models should actually be fine because they correspond to the doc_type property couchdbkit uses to decide which class to instantiate them as, which should be unique. removes explicit dependency documentation (from group.models import Group)

  Read the article

• Constrained A* problem

  - by Ragekit

  I've got a little problem with an A* algorithm that I need to Constrained a little bit. Basically : I use an A* to find the shortest path between 2 randomly placed room in 3D space, and then build a corridor between them. The problem I found is that sometimes it makes chimney like corridors that are not ideal, so I constrict the A* so that if the last movement was up or down, you go sideways. Everything is fine, but in some corner cases, it fails to find a path (when there is obviously one). Like here between the blue and red dot : (i'm in unity btw, but i don't think it matters) Here is the code of the actual A* (a bit long, and some redundency) while(current != goal) { //add stair up / stair down foreach(Node<GridUnit> test in current.Neighbors) { if(!test.Data.empty && test != goal) continue; //bug at arrival; if(test == goal && penul !=null) { Vector3 currentDiff = current.Data.bounds.center - test.Data.bounds.center; if(!Mathf.Approximately(currentDiff.y,0)) { //wanna drop on the last if(!coplanar(test.Data.bounds.center,current.Data.bounds.center,current.Data.parentUnit.bounds.center,to.Data.bounds.center)) { continue; } else { if(Mathf.Approximately(to.Data.bounds.center.x, current.Data.parentUnit.bounds.center.x) && Mathf.Approximately(to.Data.bounds.center.z, current.Data.parentUnit.bounds.center.z)) { continue; } } } } if(current.Data.parentUnit != null) { Vector3 previousDiff = current.Data.parentUnit.bounds.center - current.Data.bounds.center; Vector3 currentDiff = current.Data.bounds.center - test.Data.bounds.center; if(!Mathf.Approximately(previousDiff.y,0)) { if(!Mathf.Approximately(currentDiff.y,0)) { //you wanna drop now : continue; } if(current.Data.parentUnit.parentUnit != null) { if(!coplanar(test.Data.bounds.center,current.Data.bounds.center,current.Data.parentUnit.bounds.center,current.Data.parentUnit.parentUnit.bounds.center)) { continue; }else { if(Mathf.Approximately(test.Data.bounds.center.x, current.Data.parentUnit.parentUnit.bounds.center.x) && Mathf.Approximately(test.Data.bounds.center.z, current.Data.parentUnit.parentUnit.bounds.center.z)) { continue; } } } } } g = current.Data.g + HEURISTIC(current.Data,test.Data); h = HEURISTIC(test.Data,goal.Data); f = g + h; if(open.Contains(test) || closed.Contains(test)) { if(test.Data.f > f) { //found a shorter path going passing through that point test.Data.f = f; test.Data.g = g; test.Data.h = h; test.Data.parentUnit = current.Data; } } else { //jamais rencontré test.Data.f = f; test.Data.h = h; test.Data.g = g; test.Data.parentUnit = current.Data; open.Add(test); } } closed.Add (current); if(open.Count == 0) { Debug.Log("nothingfound"); //nothing more to test no path found, stay to from; List<GridUnit> r = new List<GridUnit>(); r.Add(from.Data); return r; } //sort open from small to biggest travel cost open.Sort(delegate(Node<GridUnit> x, Node<GridUnit> y) { return (int)(x.Data.f-y.Data.f); }); //get the smallest travel cost node; Node<GridUnit> smallest = open[0]; current = smallest; open.RemoveAt(0); } //build the path going backward; List<GridUnit> ret = new List<GridUnit>(); if(penul != null) { ret.Insert(0,to.Data); } GridUnit cur = goal.Data; ret.Insert(0,cur); do{ cur = cur.parentUnit; ret.Insert(0,cur); } while(cur != from.Data); return ret; You see at the start of the foreach i constrict the A* like i said. If you have any insight it would be cool. Thanks

  Read the article

• Is the Leptonica implementation of 'Modified Median Cut' not using the median at all?

  - by TheCodeJunkie

  I'm playing around a bit with image processing and decided to read up on how color quantization worked and after a bit of reading I found the Modified Median Cut Quantization algorithm. I've been reading the code of the C implementation in Leptonica library and came across something I thought was a bit odd. Now I want to stress that I am far from an expert in this area, not am I a math-head, so I am predicting that this all comes down to me not understanding all of it and not that the implementation of the algorithm is wrong at all. The algorithm states that the vbox should be split along the lagest axis and that it should be split using the following logic The largest axis is divided by locating the bin with the median pixel (by population), selecting the longer side, and dividing in the center of that side. We could have simply put the bin with the median pixel in the shorter side, but in the early stages of subdivision, this tends to put low density clusters (that are not considered in the subdivision) in the same vbox as part of a high density cluster that will outvote it in median vbox color, even with future median-based subdivisions. The algorithm used here is particularly important in early subdivisions, and 3is useful for giving visible but low population color clusters their own vbox. This has little effect on the subdivision of high density clusters, which ultimately will have roughly equal population in their vboxes. For the sake of the argument, let's assume that we have a vbox that we are in the process of splitting and that the red axis is the largest. In the Leptonica algorithm, on line 01297, the code appears to do the following Iterate over all the possible green and blue variations of the red color For each iteration it adds to the total number of pixels (population) it's found along the red axis For each red color it sum up the population of the current red and the previous ones, thus storing an accumulated value, for each red note: when I say 'red' I mean each point along the axis that is covered by the iteration, the actual color may not be red but contains a certain amount of red So for the sake of illustration, assume we have 9 "bins" along the red axis and that they have the following populations 4 8 20 16 1 9 12 8 8 After the iteration of all red bins, the partialsum array will contain the following count for the bins mentioned above 4 12 32 48 49 58 70 78 86 And total would have a value of 86 Once that's done it's time to perform the actual median cut and for the red axis this is performed on line 01346 It iterates over bins and check they accumulated sum. And here's the part that throws me of from the description of the algorithm. It looks for the first bin that has a value that is greater than total/2 Wouldn't total/2 mean that it is looking for a bin that has a value that is greater than the average value and not the median ? The median for the above bins would be 49 The use of 43 or 49 could potentially have a huge impact on how the boxes are split, even though the algorithm then proceeds by moving to the center of the larger side of where the matched value was.. Another thing that puzzles me a bit is that the paper specified that the bin with the median value should be located, but does not mention how to proceed if there are an even number of bins.. the median would be the result of (a+b)/2 and it's not guaranteed that any of the bins contains that population count. So this is what makes me thing that there are some approximations going on that are negligible because of how the split actually takes part at the center of the larger side of the selected bin. Sorry if it got a bit long winded, but I wanted to be as thoroughas I could because it's been driving me nuts for a couple of days now ;)

  Read the article

• High Resolution Timeouts

  - by user12607257

  The default resolution of application timers and timeouts is now 1 msec in Solaris 11.1, down from 10 msec in previous releases. This improves out-of-the-box performance of polling and event based applications, such as ticker applications, and even the Oracle rdbms log writer. More on that in a moment. As a simple example, the poll() system call takes a timeout argument in units of msec: System Calls poll(2) NAME poll - input/output multiplexing SYNOPSIS int poll(struct pollfd fds[], nfds_t nfds, int timeout); In Solaris 11, a call to poll(NULL,0,1) returns in 10 msec, because even though a 1 msec interval is requested, the implementation rounds to the system clock resolution of 10 msec. In Solaris 11.1, this call returns in 1 msec. In specification lawyer terms, the resolution of CLOCK_REALTIME, introduced by POSIX.1b real time extensions, is now 1 msec. The function clock_getres(CLOCK_REALTIME,&res) returns 1 msec, and any library calls whose man page explicitly mention CLOCK_REALTIME, such as nanosleep(), are subject to the new resolution. Additionally, many legacy functions that pre-date POSIX.1b and do not explicitly mention a clock domain, such as poll(), are subject to the new resolution. Here is a fairly comprehensive list: nanosleep pthread_mutex_timedlock pthread_mutex_reltimedlock_np pthread_rwlock_timedrdlock pthread_rwlock_reltimedrdlock_np pthread_rwlock_timedwrlock pthread_rwlock_reltimedwrlock_np mq_timedreceive mq_reltimedreceive_np mq_timedsend mq_reltimedsend_np sem_timedwait sem_reltimedwait_np poll select pselect _lwp_cond_timedwait _lwp_cond_reltimedwait semtimedop sigtimedwait aiowait aio_waitn aio_suspend port_get port_getn cond_timedwait cond_reltimedwait setitimer (ITIMER_REAL) misc rpc calls, misc ldap calls This change in resolution was made feasible because we made the implementation of timeouts more efficient a few years back when we re-architected the callout subsystem of Solaris. Previously, timeouts were tested and expired by the kernel's clock thread which ran 100 times per second, yielding a resolution of 10 msec. This did not scale, as timeouts could be posted by every CPU, but were expired by only a single thread. The resolution could be changed by setting hires_tick=1 in /etc/system, but this caused the clock thread to run at 1000 Hz, which made the potential scalability problem worse. Given enough CPUs posting enough timeouts, the clock thread could be a performance bottleneck. We fixed that by re-implementing the timeout as a per-CPU timer interrupt (using the cyclic subsystem, for those familiar with Solaris internals). This decoupled the clock thread frequency from timeout resolution, and allowed us to improve default timeout resolution without adding CPU overhead in the clock thread. Here are some exceptions for which the default resolution is still 10 msec. The thread scheduler's time quantum is 10 msec by default, because preemption is driven by the clock thread (plus helper threads for scalability). See for example dispadmin, priocntl, fx_dptbl, rt_dptbl, and ts_dptbl. This may be changed using hires_tick. The resolution of the clock_t data type, primarily used in DDI functions, is 10 msec. It may be changed using hires_tick. These functions are only used by developers writing kernel modules. A few functions that pre-date POSIX CLOCK_REALTIME mention _SC_CLK_TCK, CLK_TCK, "system clock", or no clock domain. These functions are still driven by the clock thread, and their resolution is 10 msec. They include alarm, pcsample, times, clock, and setitimer for ITIMER_VIRTUAL and ITIMER_PROF. Their resolution may be changed using hires_tick. Now back to the database. How does this help the Oracle log writer? Foreground processes post a redo record to the log writer, which releases them after the redo has committed. When a large number of foregrounds are waiting, the release step can slow down the log writer, so under heavy load, the foregrounds switch to a mode where they poll for completion. This scales better because every foreground can poll independently, but at the cost of waiting the minimum polling interval. That was 10 msec, but is now 1 msec in Solaris 11.1, so the foregrounds process transactions faster under load. Pretty cool.

  Read the article

• GCM: onMessage() from GCMIntentService is never called [migrated]

  - by Shrikant

  I am implementing GCM (Google Cloud Messaging- PUSH Notifications) in my application. I have followed all the steps given in GCM tutorial from developer.android.com My application's build target is pointing to Goolge API 8 (Android 2.2 version). I am able to get the register ID from GCM successfully, and I am passing this ID to my application server. So the registration step is performed successfully. Now when my application server sends a PUSH message to my device, the server gets the message as SUCCESS=1 FAILURE=0, etc., i.e. Server is sending message successfully, but my device never receives the message. After searching alot about this, I came to know that GCM pushes messages on port number 5228, 5229 or 5230. Initially, my device and laptop was restricted for some websites, but then I was granted all the permissions to access all websites, so I guess these port numbers are open for my device. So my question is: I never receive any PUSH message from GCM. My onMessage() from GCMIntenService class is never called. What could be the reason? Please see my following code and guide me accordingly: I have declared following in my manifest: <uses-sdk android:minSdkVersion="8" android:targetSdkVersion="8" /> <permission android:name="package.permission.C2D_MESSAGE" android:protectionLevel="signature" /> <!-- App receives GCM messages. --> <uses-permission android:name="com.google.android.c2dm.permission.RECEIVE" /> <!-- GCM connects to Google Services. --> <uses-permission android:name="android.permission.INTERNET" /> <!-- GCM requires a Google account. --> <uses-permission android:name="android.permission.GET_ACCOUNTS" /> <!-- Keeps the processor from sleeping when a message is received. --> <uses-permission android:name="android.permission.WAKE_LOCK" /> <uses-permission android:name="package.permission.C2D_MESSAGE" /> <uses-permission android:name="android.permission.INTERNET" /> <receiver android:name="com.google.android.gcm.GCMBroadcastReceiver" android:permission="com.google.android.c2dm.permission.SEND" > <intent-filter> <action android:name="com.google.android.c2dm.intent.RECEIVE" /> <action android:name="com.google.android.c2dm.intent.REGISTRATION" /> <category android:name="packageName" /> </intent-filter> </receiver> <receiver android:name=".ReceiveBroadcast" android:exported="false" > <intent-filter> <action android:name="GCM_RECEIVED_ACTION" /> </intent-filter> </receiver> <service android:name=".GCMIntentService" /> /** * @author Shrikant. * */ public class GCMIntentService extends GCMBaseIntentService { /** * The Sender ID used for GCM. */ public static final String SENDER_ID = "myProjectID"; /** * This field is used to call Web-Service for GCM. */ SendUserCredentialsGCM sendUserCredentialsGCM = null; public GCMIntentService() { super(SENDER_ID); sendUserCredentialsGCM = new SendUserCredentialsGCM(); } @Override protected void onRegistered(Context arg0, String registrationId) { Log.i(TAG, "Device registered: regId = " + registrationId); sendUserCredentialsGCM.sendRegistrationID(registrationId); } @Override protected void onUnregistered(Context context, String arg1) { Log.i(TAG, "unregistered = " + arg1); sendUserCredentialsGCM .unregisterFromGCM(LoginActivity.API_OR_BROWSER_KEY); } @Override protected void onMessage(Context context, Intent intent) { Log.e("GCM MESSAGE", "Message Recieved!!!"); String message = intent.getStringExtra("message"); if (message == null) { Log.e("NULL MESSAGE", "Message Not Recieved!!!"); } else { Log.i(TAG, "new message= " + message); sendGCMIntent(context, message); } } private void sendGCMIntent(Context context, String message) { Intent broadcastIntent = new Intent(); broadcastIntent.setAction("GCM_RECEIVED_ACTION"); broadcastIntent.putExtra("gcm", message); context.sendBroadcast(broadcastIntent); } @Override protected void onError(Context context, String errorId) { Log.e(TAG, "Received error: " + errorId); Toast.makeText(context, "PUSH Notification failed.", Toast.LENGTH_LONG) .show(); } @Override protected boolean onRecoverableError(Context context, String errorId) { return super.onRecoverableError(context, errorId); } }

  Read the article

• Reading graph inputs for a programming puzzle and then solving it

  - by Vrashabh

  I just took a programming competition question and I absolutely bombed it. I had trouble right at the beginning itself from reading the input set. The question was basically a variant of this puzzle http://codercharts.com/puzzle/evacuation-plan but also had an hour component in the first line(say 3 hours after start of evacuation). It reads like this This puzzle is a tribute to all the people who suffered from the earthquake in Japan. The goal of this puzzle is, given a network of road and locations, to determine the maximum number of people that can be evacuated. The people must be evacuated from evacuation points to rescue points. The list of road and the number of people they can carry per hour is provided. Input Specifications Your program must accept one and only one command line argument: the input file. The input file is formatted as follows: the first line contains 4 integers n r s t n is the number of locations (each location is given by a number from 0 to n-1) r is the number of roads s is the number of locations to be evacuated from (evacuation points) t is the number of locations where people must be evacuated to (rescue points) the second line contains s integers giving the locations of the evacuation points the third line contains t integers giving the locations of the rescue points the r following lines contain to the road definitions. Each road is defined by 3 integers l1 l2 width where l1 and l2 are the locations connected by the road (roads are one-way) and width is the number of people per hour that can fit on the road Now look at the sample input set 5 5 1 2 3 0 3 4 0 1 10 0 2 5 1 2 4 1 3 5 2 4 10 The 3 in the first line is the additional component and is defined as the number of hours since the resuce has started which is 3 in this case. Now my solution was to use Dijisktras algorithm to find the shortest path between each of the rescue and evac nodes. Now my problem started with how to read the input set. I read the first line in python and stored the values in variables. But then I did not know how to store the values of the distance between the nodes and what DS to use and how to input it to say a standard implementation of dijikstras algorithm. So my question is two fold 1.) How do I take the input of such problems? - I have faced this problem in quite a few competitions recently and I hope I can get a simple code snippet or an explanation in java or python to read the data input set in such a way that I can input it as a graph to graph algorithms like dijikstra and floyd/warshall. Also a solution to the above problem would also help. 2.) How to solve this puzzle? My algorithm was: Find shortest path between evac points (in the above example it is 14 from 0 to 3) Multiply it by number of hours to get maximal number of saves Also the answer given for the variant for the input set was 24 which I dont understand. Can someone explain that also. UPDATE: I get how the answer is 14 in the given problem link - it seems to be just the shortest path between node 0 and 3. But with the 3 hour component how is the answer 24 UPDATE I get how it is 24 - its a complete graph traversal at every hour and this is how I solve it Hour 1 Node 0 to Node 1 - 10 people Node 0 to Node 2- 5 people TotalRescueCount=0 Node 1=10 Node 2= 5 Hour 2 Node 1 to Node 3 = 5(Rescued) Node 2 to Node 4 = 5(Rescued) Node 0 to Node 1 = 10 Node 0 to Node 2 = 5 Node 1 to Node 2 = 4 TotalRescueCount = 10 Node 1 = 10 Node 2= 5+4 = 9 Hour 3 Node 1 to Node 3 = 5(Rescued) Node 2 to Node 4 = 5+4 = 9(Rescued) TotalRescueCount = 9+5+10 = 24 It hard enough for this case , for multiple evac and rescue points how in the world would I write a pgm for this ?

  Read the article

• Mercurial fails while commiting/updating/etc. using Mercuriual+TrueCrypt+MAC

  - by lukewar

  While trying to work with Mercurial on project located on TrueCrypt partition I always get en error as follows: ** unknown exception encountered, details follow ** report bug details to http://mercurial.selenic.com/bts/ ** or [email protected] ** Mercurial Distributed SCM (version 1.5.2+20100502) ** Extensions loaded: Traceback (most recent call last): File "/usr/local/bin/hg", line 27, in mercurial.dispatch.run() File "/Library/Python/2.6/site-packages/mercurial/dispatch.py", line 16, in run sys.exit(dispatch(sys.argv[1:])) File "/Library/Python/2.6/site-packages/mercurial/dispatch.py", line 30, in dispatch return _runcatch(u, args) File "/Library/Python/2.6/site-packages/mercurial/dispatch.py", line 50, in _runcatch return _dispatch(ui, args) File "/Library/Python/2.6/site-packages/mercurial/dispatch.py", line 470, in _dispatch return runcommand(lui, repo, cmd, fullargs, ui, options, d) File "/Library/Python/2.6/site-packages/mercurial/dispatch.py", line 340, in runcommand ret = _runcommand(ui, options, cmd, d) File "/Library/Python/2.6/site-packages/mercurial/dispatch.py", line 521, in _runcommand return checkargs() File "/Library/Python/2.6/site-packages/mercurial/dispatch.py", line 475, in checkargs return cmdfunc() File "/Library/Python/2.6/site-packages/mercurial/dispatch.py", line 469, in d = lambda: util.checksignature(func)(ui, *args, **cmdoptions) File "/Library/Python/2.6/site-packages/mercurial/util.py", line 401, in check return func(*args, **kwargs) File "/Library/Python/2.6/site-packages/mercurial/commands.py", line 3332, in update return hg.update(repo, rev) File "/Library/Python/2.6/site-packages/mercurial/hg.py", line 362, in update stats = _merge.update(repo, node, False, False, None) File "/Library/Python/2.6/site-packages/mercurial/merge.py", line 495, in update _checkunknown(wc, p2) File "/Library/Python/2.6/site-packages/mercurial/merge.py", line 77, in _checkunknown for f in wctx.unknown(): File "/Library/Python/2.6/site-packages/mercurial/context.py", line 660, in unknown return self._status[4] File "/Library/Python/2.6/site-packages/mercurial/util.py", line 156, in get result = self.func(obj) File "/Library/Python/2.6/site-packages/mercurial/context.py", line 622, in _status return self._repo.status(unknown=True) File "/Library/Python/2.6/site-packages/mercurial/localrepo.py", line 1023, in status if (f not in ctx1 or ctx2.flags(f) != ctx1.flags(f) File "/Library/Python/2.6/site-packages/mercurial/context.py", line 694, in flags flag = findflag(self._parents[0]) File "/Library/Python/2.6/site-packages/mercurial/context.py", line 690, in findflag return ff(path) File "/Library/Python/2.6/site-packages/mercurial/dirstate.py", line 145, in f if 'x' in fallback(x): TypeError: argument of type 'NoneType' is not iterable It is worth mention that Mercurial works perfectly if project is not located on TrueCrypt partition. Configuration: MacOS X 10.6.3 Mercurial Distributed SCM (version 1.5.2+20100502) Python 2.6.5 Have anyone of you generous people able to help me? :)

  Read the article

• X509Certificate.CreateFromCertFile - the specified network password is not correct

  - by pcampbell

  I have a .NET application that I want to use as a client to call an SSL SOAP web service. I have been supplied with a valid client certificate called foo.pfx. There is a password on the certificate itself. I've located the certificate at the following location: C:\certs\foo.pfx To call the web service, I need to attach the client certificate. Here's the code: public X509Certificate GetCertificateFromDisk(){ try{ string certPath = ConfigurationManager.AppSettings["MyCertPath"].ToString(); //this evaluates to "c:\\certs\\foo.pfx". So far so good. X509Certificate myCert = X509Certificate.CreateFromCertFile(certPath); // exception is raised here! "The specified network password is not correct" return cert; } catch (Exception ex){ throw; } } It sounds like the exception is around the .NET application trying to read the disk. The method CreateFromCertFile is a static method that should create a new instance of X509Certificate. The method isn't overridden, and has only one argument: the path. When I inspect the Exception, I find this: _COMPlusExceptionCode = -532459699 Source=mscorlib Question: does anyone know what the cause of the exception "The specified network password is not correct" ?

  Read the article

< Previous Page | 239 240 241 242 243 244 245 246 247 248 249 250  | Next Page >