Search Results

Search found 37841 results on 1514 pages for 'object state'.

Page 353/1514 | < Previous Page | 349 350 351 352 353 354 355 356 357 358 359 360  | Next Page >

• Saving Big Money With Open Source Storage

  One company turned to iSCSI, OpenSolaris and Linux, commodity hardware and even solid state drives to control data storage costs.

  Read the article

• Entity Type specific updates in entity component system

  - by Nathan

  I am currently familiarizing myself with the entity component paradigm. For an example, take a collision system, that detects if entities collide and if they do let them explode. So the collision system has to test collision based on the position component and then set the state of those entities to exploding. But what if the "effect" (setting the state to exploding) is different for different entities? For example, a ship fades out while for an asteroid a particle system must be created. Since entities and components are only data, this must happen in some system. The collision system could do it, but then it must switch over the entity type, which in my opinion is a cumbersome and difficult to extend solution. So how do I trigger "entity type dependend" updates on an entity?

  Read the article

• Canon Mx772 printer recognized, drivers loaded...but all print jobs "Held"

  - by user212169

  BRAND NEW to Ubuntu but loving it so far. I have a Canon MX772 wireless printing running on my network and am able to print fine from a PC and Mac. Using the printers IP, Ubuntu was able to find it and I accepted all of the "recommended" items (it found a Canon MX770 driver). Everything seems to load fine...but the test page does not print, nor does any print commands make it to the printer. If I open the print dialogue jobs are shown as "held" and when I look at the jobs attributes, I see "Job printer state message=cannot specify model number" and then a few lines down "job state reasons=aborted by system". If I try to "resume" it immediately goes back to "held". I can successfully ping the IP of the printer. Would be very appreciative of other ideas...printing is the last check in the box before I am all set up. Thanks!

  Read the article

• Trying to install Team viewer on Ubuntu 12.04

  - by Teknikk

  I recently got Ubuntu installed on my server, I wanted to install TeamViewer so i could easy manage the virtual machines, However, I get errors when installing it from App store?, And I also get errors, but more detailed on the terminal. Error output: tek@tek-G53SW:~/Download$ sudo dpkg -i ipts teamviewer_linux_x64.deb dpkg: error processing ipts (--install): cannot access archive: No such file or directory (Reading database ... 142115 files and directories currently installed.) Preparing to replace teamviewer7 7.0.9360 (using teamviewer_linux_x64.deb) ... Unpacking replacement teamviewer7 ... dpkg: dependency problems prevent configuration of teamviewer7: teamviewer7 depends on libc6-i386 (>= 2.7); however: Package libc6-i386 is not installed. teamviewer7 depends on lib32asound2; however: Package lib32asound2 is not installed. teamviewer7 depends on lib32z1; however: Package lib32z1 is not installed. teamviewer7 depends on ia32-libs; however: Package ia32-libs is not installed. dpkg: error processing teamviewer7 (--install): dependency problems - leaving unconfigured Errors were encountered while processing: ipts teamviewer7 I tried to install it manually, but with no luck, I heard some others has this problems. I am running Ubuntu 12.04 x64. Error @ sudo apt-get install libc6-i386 lib32asound2 lib32z1 ia32-libs : tek@tek-G53SW:~/Download$ sudo apt-get install libc6-i386 lib32asound2 lib32z1 ia32-libs Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies: ia32-libs : Depends: ia32-libs-multiarch E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution). tek@tek-G53SW:~/Download$ More errors tek@tek-G53SW:~/Download$ sudo apt-get -f install [sudo] password for tek: Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following packages will be REMOVED: teamviewer7 0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded. 1 not fully installed or removed. After this operation, 81.9 MB disk space will be freed. Do you want to continue [Y/n]? y (Reading database ... 142441 files and directories currently installed.) Removing teamviewer7 ... tek@tek-G53SW:~/Download$ sudo apt-get install libc6-i386 lib32asound2 lib32z1 ia32-libs Reading package lists... Done Building dependency tree Reading state information... Done lib32z1 is already the newest version. libc6-i386 is already the newest version. lib32asound2 is already the newest version. Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: ia32-libs : Depends: ia32-libs-multiarch E: Unable to correct problems, you have held broken packages. tek@tek-G53SW:~/Download$ sudo apt-get install ia32-libs-multiarch Reading package lists... Done Building dependency tree Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: ia32-libs-multiarch:i386 : Depends: gstreamer0.10-plugins-good:i386 but it is not going to be installed Depends: gtk2-engines:i386 but it is not going to be installed Depends: gtk2-engines-murrine:i386 but it is not going to be installed Depends: gtk2-engines-pixbuf:i386 but it is not going to be installed Depends: gtk2-engines-oxygen:i386 but it is not going to be installed Depends: ibus-gtk:i386 but it is not going to be installed Depends: libcanberra-gtk-module:i386 but it is not going to be installed Depends: libcups2:i386 but it is not going to be installed Depends: libcupsimage2:i386 but it is not going to be installed Depends: libfontconfig1:i386 but it is not going to be installed Depends: libgail-common:i386 but it is not going to be installed Depends: libgphoto2-2:i386 but it is not going to be installed Depends: libgtk2.0-0:i386 but it is not going to be installed Depends: libnss3:i386 but it is not going to be installed Depends: libqt4-opengl:i386 but it is not going to be installed Depends: libqt4-qt3support:i386 but it is not going to be installed Depends: libqt4-scripttools:i386 but it is not going to be installed Depends: libqt4-svg:i386 but it is not going to be installed Depends: libqtgui4:i386 but it is not going to be installed Depends: libqtwebkit4:i386 but it is not going to be installed Depends: librsvg2-common:i386 but it is not going to be installed Depends: libsane:i386 but it is not going to be installed E: Unable to correct problems, you have held broken packages. tek@tek-G53SW:~/Download$

  Read the article

• Sub routing in a SPA site

  - by Anders

  I have a SPA site that I'm working on, I have a requirement that you can have subroutes for a page view model. Im currently using this 'pattern' for the site MyApp.FooViewModel = MyApp.define({ meta: { query: MyApp.Core.Contracts.Queries.FooQuery, title: "Foo" }, init: function (queryResult) { }, prototype: { } }); In the master view model I have a route table this.navigation(new MyApp.RoutesViewModel({ Home: { model: MyApp.HomeViewModel, route: String.empty }, Foo: { model: MyApp.FooViewModel } })); The meta object defines which query should populate the top level view model when its invoked through sammyjs, this is all fine but it does not support sub routing My plan is to change the meta object so that it can (optional offcourse) look like this meta: { query: MyApp.Core.Contracts.Queries.FooQuery, title: "Foo", route: { barId: MyApp.BarViewModel } } When sammyjs detects a barId in the query string the Barmodel will be executed and populated through its own meta object. Is this a good design?

  Read the article

• Cocos2d-x 3.0 animation frame by frame

  - by Narek

  As I know animations are actions. Now I need to play animation frame by frame. Say I have an animation from N frames. each frame should be played after t delay. Now I want to play animation frame by frame, each frame advance the animation's state. How I can do this? And what about playing actions frame by frame advancing the state in general. I ask because I use ECS, and I deal with frames. P.S. I want to do something like this: Action * a = MoveTo(initialPoint, finalPoint, durationOfAnimation); a->play(0.001 seconds); a->play(0.003 seconds); a->play(0.02 seconds); a->play(0.67 seconds); a->play(0.06 seconds); And see the animation.

  Read the article

• Designing Mobile SMS text advertising system

  - by Ramraj Edagutti

  Currently, I am working on a product where we have an SMS text advertising system, and using this, we setup advertising campaigns for clients, and later these campaigns are sent to the end users. This is very similar to Google Adwords, but targeted to Mobile users via SMS. Just to give an overview of the system Each Campaign is mapped to an advertiser Campaign has start date and end date Campaign has a filter condition(s) or query to select the target user base from our database (to whom we send Campaigns) Target user base can be fixed, for e.g send campaign to 10000 users Target user base can also be dynamic based on query condition, for e.g send campaign to users who are active and from a particular state, district, town etc. (this way user base will be keep changing on daily basis) Campaign can have multiple campaign messages Each campaign message has start date and end date Each campaign message can have multiple message texts for different locales, for e.g English,Hindi,Telugu etc After creating an advertisement campaign, we run daily night job to provision the target user base for that a particular campaign in a separate table, and another daily job runs on morning times and checks provisioned table for campaigns and targeted users and sends the campaign to users via SMS. Problem is, current UI for creating advertising campaigns is designed in a very technical manner, I mean, normal user or business owner or clients can not use the UI to create a campaign. Below are reasons why the UI is very technical in nature Filter condition(s) or query input filed, takes user ids or mobile numbers or SQL queries. Most of times or almost every time, we use big SQL queries So we end up storing SQL queries in a database for a campaign, later we use this SQL query to fetch targeted user base. For scheduling these campaigns, we have input filed on UI which takes quartz cron expression(s) ( for e.g. send campaign on "0 0 9 1-10 MAR 2012" ), again very technical in nature Normal user or business owner, can not use the UI for creating campaigns for reasons mentioned above, Currently, we ourself (developers) helping clients to setup/create campaigns. we are trying to re-design the UI to make it more user friendly so that any user can go to UI and create an advertisement campaign by himself. I am thinking of re-designing the current UI similar to Google Adwords interface, especially for selecting target users based on user geography like country, state, city etc. I also need to select users based user subscription(s), which might make system even more complex. And also, for campaign scheduling, I am thinking of using weekdays with hours. For example, I will shows Monday to Sunday on UI, and user can select the from hours, to hours etc. Any better ideas or suggestion on how to design UI in very user friendly manner and what design should be followed on server side code (we write backend code on java/jpa/spring/quartz)? And I am looking for ideas or design patterns on how to build SQL queries (using JPA/Hinernate) programmatically on server side, based on varies conditions like based on country, state, town, village, and user subscriptions.

  Read the article

• Oracle HRMS APIs

  - by PRajkumar

  Oracle HRMS APIs..... Here I will be sharing all the Oracle HRMS APIs related articles. Item Type Author 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Create Employee API Update Employee API Create Employee Contact API Create Employee Address API Update Employee Address API Create Element Entries for Employee API Delete Element Entries for Employee API Rehire Employee API Create Employee Payment Method API Create and Update Employee Phone API Create and Update Employee Salary Proposal API Update Employee Fed Tax Rule API Create Employee State Tax Rule API Update Employee State Tax Rule API Update Employee Assignment API Puneet Rajkumar Puneet Rajkumar Puneet Rajkumar Puneet Rajkumar Puneet Rajkumar Puneet Rajkumar Puneet Rajkumar Puneet Rajkumar Puneet Rajkumar Puneet Rajkumar Puneet Rajkumar Puneet Rajkumar Puneet Rajkumar Puneet Rajkumar Puneet Rajkumar

  Read the article

• Builder Pattern: When to fail?

  - by skiwi

  When implementing the Builder Pattern, I often find myself confused with when to let building fail and I even manage to take different stands on the matter every few days. First some explanation: With failing early I mean that building an object should fail as soon as an invalid parameter is passed in. So inside the SomeObjectBuilder. With failing late I mean that building an object only can fail on the build() call that implicitely calls a constructor of the object to be built. Then some arguments: In favor of failing late: A builder class should be no more than a class that simply holds values. Moreover, it leads to less code duplication. In favor of failing early: A general approach in software programming is that you want to detect issues as early as possible and therefore the most logical place to check would be in the builder class' constructor, 'setters' and ultimately in the build method. What is the general concensus about this?

  Read the article

• Can't remove the libpcap0.8 package

  - by Yogesh

  I am getting error when running apt-get remove root@System:~/Downloads# sudo apt-get remove The following packages have unmet dependencies: libpcap0.8 : Breaks: libpcap0.8:i386 (!= 1.4.0-2) but 1.5.3-2 is installed libpcap0.8:i386 : Breaks: libpcap0.8 (!= 1.5.3-2) but 1.4.0-2 is installed libpcap0.8-dev : Depends: libpcap0.8 (= 1.5.3-2) but 1.4.0-2 is installed E: Unmet dependencies. Try using -f. and when I ran apt-get remove -f this is what happens: root@System:~/Downloads# sudo apt-get remove -f The following extra packages will be installed: libpcap0.8 The following packages will be upgraded: libpcap0.8 1 upgraded, 0 newly installed, 0 to remove and 365 not upgraded. 2 not fully installed or removed. Need to get 0 B/110 kB of archives. After this operation, 13.3 kB of additional disk space will be used. Do you want to continue? [Y/n] y (Reading database ... 163539 files and directories currently installed.) Preparing to unpack .../libpcap0.8_1.5.3-2_amd64.deb ... Unpacking libpcap0.8:amd64 (1.5.3-2) over (1.4.0-2) ... dpkg: error processing archive /var/cache/apt/archives/libpcap0.8_1.5.3-2_amd64.deb (--unpack): trying to overwrite shared '/usr/share/man/man7/pcap-filter.7.gz', which is different from other instances of package libpcap0.8:amd64 dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Processing triggers for man-db (2.6.7.1-1) ... Errors were encountered while processing: /var/cache/apt/archives/libpcap0.8_1.5.3-2_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1) root@System:~/Downloads# clear root@System:~/Downloads# sudo apt-get remove -f Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following extra packages will be installed: libpcap0.8 The following packages will be upgraded: libpcap0.8 1 upgraded, 0 newly installed, 0 to remove and 365 not upgraded. 2 not fully installed or removed. Need to get 0 B/110 kB of archives. After this operation, 13.3 kB of additional disk space will be used. Do you want to continue? [Y/n] y (Reading database ... 163539 files and directories currently installed.) Preparing to unpack .../libpcap0.8_1.5.3-2_amd64.deb ... Unpacking libpcap0.8:amd64 (1.5.3-2) over (1.4.0-2) ... dpkg: error processing archive /var/cache/apt/archives/libpcap0.8_1.5.3-2_amd64.deb (--unpack): trying to overwrite shared '/usr/share/man/man7/pcap-filter.7.gz', which is different from other instances of package libpcap0.8:amd64 dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Processing triggers for man-db (2.6.7.1-1) ... Errors were encountered while processing: /var/cache/apt/archives/libpcap0.8_1.5.3-2_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1) root@System:~/Downloads# root@System:~/Downloads# sudo apt-get check Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies: libpcap0.8 : Breaks: libpcap0.8:i386 (!= 1.4.0-2) but 1.5.3-2 is installed libpcap0.8:i386 : Breaks: libpcap0.8 (!= 1.5.3-2) but 1.4.0-2 is installed libpcap0.8-dev : Depends: libpcap0.8 (= 1.5.3-2) but 1.4.0-2 is installed E: Unmet dependencies. Try using -f. root@System:~/Downloads# apt-cache policy libpcap0.8:amd64 libpcap0.8 libpcap0.8-dev libpcap0.8: Installed: 1.4.0-2 Candidate: 1.5.3-2 Version table: 1.5.3-2 0 500 http://in.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages *** 1.4.0-2 0 100 /var/lib/dpkg/status libpcap0.8: Installed: 1.4.0-2 Candidate: 1.5.3-2 Version table: 1.5.3-2 0 500 http://in.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages *** 1.4.0-2 0 100 /var/lib/dpkg/status libpcap0.8-dev: Installed: 1.5.3-2 Candidate: 1.5.3-2 Version table: *** 1.5.3-2 0 500 http://in.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages 100 /var/lib/dpkg/status root@System:~/Downloads# root@System:~/Downloads# sudo apt-get -f remove libpcap0.8 libpcap0.8-dev libpcap0.8-dev:i386 libpcap0.8:i386 Reading package lists... Done Building dependency tree Reading state information... Done Package 'libpcap0.8-dev:i386' is not installed, so not removed. Did you mean 'libpcap0.8-dev'? You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies: libpcap-dev : Depends: libpcap0.8-dev but it is not going to be installed E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution). root@System:~/Downloads# sudo apt-get -f install Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following extra packages will be installed: libpcap0.8 The following packages will be upgraded: libpcap0.8 1 upgraded, 0 newly installed, 0 to remove and 365 not upgraded. 2 not fully installed or removed. Need to get 0 B/110 kB of archives. After this operation, 13.3 kB of additional disk space will be used. Do you want to continue? [Y/n] y (Reading database ... 163539 files and directories currently installed.) Preparing to unpack .../libpcap0.8_1.5.3-2_amd64.deb ... Unpacking libpcap0.8:amd64 (1.5.3-2) over (1.4.0-2) ... dpkg: error processing archive /var/cache/apt/archives/libpcap0.8_1.5.3-2_amd64.deb (--unpack): trying to overwrite shared '/usr/share/man/man7/pcap-filter.7.gz', which is different from other instances of package libpcap0.8:amd64 dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Processing triggers for man-db (2.6.7.1-1) ... Errors were encountered while processing: /var/cache/apt/archives/libpcap0.8_1.5.3-2_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1) root@System:~/Downloads#

  Read the article

• does eCryptfs support multiple users?

  - by new to eCryptfs

  I'm new to ecryptfs and I need some clarification on how it works. Suppose there are two root users userA and userB, If I mount some folder under userA: [userA@Dev] $ mount ecryptfs real img now I can visit the img folder to access decrypted data. My questions is: While userA is still in log in state. Can userB login and access the decrypted data? This is currently what I observed on my local machine, but I'm not sure if it was cause by my misconfiguration. If it is the case, how can I avoid other users from accessing the decrypted data while userA is in login state?

  Read the article

• Nagging As A Strategy For Better Linking: -z guidance

  - by user9154181

  The link-editor (ld) in Solaris 11 has a new feature that we call guidance that is intended to help you build better objects. The basic idea behind guidance is that if (and only if) you request it, the link-editor will issue messages suggesting better options and other changes you might make to your ld command to get better results. You can choose to take the advice, or you can disable specific types of guidance while acting on others. In some ways, this works like an experienced friend leaning over your shoulder and giving you advice — you're free to take it or leave it as you see fit, but you get nudged to do a better job than you might have otherwise. We use guidance to build the core Solaris OS, and it has proven to be useful, both in improving our objects, and in making sure that regressions don't creep back in later. In this article, I'm going to describe the evolution in thinking and design that led to the implementation of the -z guidance option, as well as give a brief description of how it works. The guidance feature issues non-fatal warnings. However, experience shows that once developers get used to ignoring warnings, it is inevitable that real problems will be lost in the noise and ignored or missed. This is why we have a zero tolerance policy against build noise in the core Solaris OS. In order to get maximum benefit from -z guidance while maintaining this policy, I added the -z fatal-warnings option at the same time. Much of the material presented here is adapted from the arc case: PSARC 2010/312 Link-editor guidance The History Of Unfortunate Link-Editor Defaults The Solaris link-editor is one of the oldest Unix commands. It stands to reason that this would be true — in order to write an operating system, you need the ability to compile and link code. The original link-editor (ld) had defaults that made sense at the time. As new features were needed, command line option switches were added to let the user use them, while maintaining backward compatibility for those who didn't. Backward compatibility is always a concern in system design, but is particularly important in the case of the tool chain (compilers, linker, and related tools), since it is a basic building block for the entire system. Over the years, applications have grown in size and complexity. Important concepts like dynamic linking that didn't exist in the original Unix system were invented. Object file formats changed. In the case of System V Release 4 Unix derivatives like Solaris, the ELF (Extensible Linking Format) was adopted. Since then, the ELF system has evolved to provide tools needed to manage today's larger and more complex environments. Features such as lazy loading, and direct bindings have been added. In an ideal world, many of these options would be defaults, with rarely used options that allow the user to turn them off. However, the reality is exactly the reverse: For backward compatibility, these features are all options that must be explicitly turned on by the user. This has led to a situation in which most applications do not take advantage of the many improvements that have been made in linking over the last 20 years. If their code seems to link and run without issue, what motivation does a developer have to read a complex manpage, absorb the information provided, choose the features that matter for their application, and apply them? Experience shows that only the most motivated and diligent programmers will make that effort. We know that most programs would be improved if we could just get you to use the various whizzy features that we provide, but the defaults conspire against us. We have long wanted to do something to make it easier for our users to use the linkers more effectively. There have been many conversations over the years regarding this issue, and how to address it. They always break down along the following lines: Change ld Defaults Since the world would be a better place the newer ld features were the defaults, why not change things to make it so? This idea is simple, elegant, and impossible. Doing so would break a large number of existing applications, including those of ISVs, big customers, and a plethora of existing open source packages. In each case, the owner of that code may choose to follow our lead and fix their code, or they may view it as an invitation to reconsider their commitment to our platform. Backward compatibility, and our installed base of working software, is one of our greatest assets, and not something to be lightly put at risk. Breaking backward compatibility at this level of the system is likely to do more harm than good. But, it sure is tempting. New Link-Editor One might create a new linker command, not called 'ld', leaving the old command as it is. The new one could use the same code as ld, but would offer only modern options, with the proper defaults for features such as direct binding. The resulting link-editor would be a pleasure to use. However, the approach is doomed to niche status. There is a vast pile of exiting code in the world built around the existing ld command, that reaches back to the 1970's. ld use is embedded in large and unknown numbers of makefiles, and is used by name by compilers that execute it. A Unix link-editor that is not named ld will not find a majority audience no matter how good it might be. Finally, a new linker command will eventually cease to be new, and will accumulate its own burden of backward compatibility issues. An Option To Make ld Do The Right Things Automatically This line of reasoning is best summarized by a CR filed in 2005, entitled 6239804 make it easier for ld(1) to do what's best The idea is to have a '-z best' option that unchains ld from its backward compatibility commitment, and allows it to turn on the "best" set of features, as determined by the authors of ld. The specific set of features enabled by -z best would be subject to change over time, as requirements change. This idea is more realistic than the other two, but was never implemented because it has some important issues that we could never answer to our satisfaction: The -z best proposal assumes that the user can turn it on, and trust it to select good options without the user needing to be aware of the options being applied. This is a fallacy. Features such as direct bindings require the user to do some analysis to ensure that the resulting program will still operate properly. A user who is willing to do the work to verify that what -z best does will be OK for their application is capable of turning on those features directly, and therefore gains little added benefit from -z best. The intent is that when a user opts into -z best, that they understand that z best is subject to sometimes incompatible evolution. Experience teaches us that this won't work. People will use this feature, the meaning of -z best will change, code that used to build will fail, and then there will be complaints and demands to retract the change. When (not if) this occurs, we will of course defend our actions, and point at the disclaimer. We'll win some of those debates, and lose others. Ultimately, we'll end up with -z best2 (-z better), or other compromises, and our goal of simplifying the world will have failed. The -z best idea rolls up a set of features that may or may not be related to each other into a unit that must be taken wholesale, or not at all. It could be that only a subset of what it does is compatible with a given application, in which case the user is expected to abandon -z best and instead set the options that apply to their application directly. In doing so, they lose one of the benefits of -z best, that if you use it, future versions of ld may choose a different set of options, and automatically improve the object through the act of rebuilding it. I drew two conclusions from the above history: For a link-editor, backward compatibility is vital. If a given command line linked your application 10 years ago, you have every reason to expect that it will link today, assuming that the libraries you're linking against are still available and compatible with their previous interfaces. For an application of any size or complexity, there is no substitute for the work involved in examining the code and determining which linker options apply and which do not. These options are largely orthogonal to each other, and it can be reasonable not to use any or all of them, depending on the situation, even in modern applications. It is a mistake to tie them together. The idea for -z guidance came from consideration of these points. By decoupling the advice from the act of taking the advice, we can retain the good aspects of -z best while avoiding its pitfalls: -z guidance gives advice, but the decision to take that advice remains with the user who must evaluate its merit and make a decision to take it or not. As such, we are free to change the specific guidance given in future releases of ld, without breaking existing applications. The only fallout from this will be some new warnings in the build output, which can be ignored or dealt with at the user's convenience. It does not couple the various features given into a single "take it or leave it" option, meaning that there will never be a need to offer "-zguidance2", or other such variants as things change over time. Guidance has the potential to be our final word on this subject. The user is given the flexibility to disable specific categories of guidance without losing the benefit of others, including those that might be added to future versions of the system. Although -z fatal-warnings stands on its own as a useful feature, it is of particular interest in combination with -z guidance. Used together, the guidance turns from advice to hard requirement: The user must either make the suggested change, or explicitly reject the advice by specifying a guidance exception token, in order to get a build. This is valuable in environments with high coding standards. ld Command Line Options The guidance effort resulted in new link-editor options for guidance and for turning warnings into fatal errors. Before I reproduce that text here, I'd like to highlight the strategic decisions embedded in the guidance feature: In order to get guidance, you have to opt in. We hope you will opt in, and believe you'll get better objects if you do, but our default mode of operation will continue as it always has, with full backward compatibility, and without judgement. Guidance suggestions always offers specific advice, and not vague generalizations. You can disable some guidance without turning off the entire feature. When you get guidance warnings, you can choose to take the advice, or you can specify a keyword to disable guidance for just that category. This allows you to get guidance for things that are useful to you, without being bothered about things that you've already considered and dismissed. As the world changes, we will add new guidance to steer you in the right direction. All such new guidance will come with a keyword that let's you turn it off. In order to facilitate building your code on different versions of Solaris, we quietly ignore any guidance keywords we don't recognize, assuming that they are intended for newer versions of the link-editor. If you want to see what guidance tokens ld does and does not recognize on your system, you can use the ld debugging feature as follows: % ld -Dargs -z guidance=foo,nodefs debug: debug: Solaris Linkers: 5.11-1.2275 debug: debug: arg[1] option=-D: option-argument: args debug: arg[2] option=-z: option-argument: guidance=foo,nodefs debug: warning: unrecognized -z guidance item: foo The -z fatal-warning option is straightforward, and generally useful in environments with strict coding standards. Note that the GNU ld already had this feature, and we accept their option names as synonyms: -z fatal-warnings | nofatal-warnings --fatal-warnings | --no-fatal-warnings The -z fatal-warnings and the --fatal-warnings option cause the link-editor to treat warnings as fatal errors. The -z nofatal-warnings and the --no-fatal-warnings option cause the link-editor to treat warnings as non-fatal. This is the default behavior. The -z guidance option is defined as follows: -z guidance[=item1,item2,...] Provide guidance messages to suggest ld options that can improve the quality of the resulting object, or which are otherwise considered to be beneficial. The specific guidance offered is subject to change over time as the system evolves. Obsolete guidance offered by older versions of ld may be dropped in new versions. Similarly, new guidance may be added to new versions of ld. Guidance therefore always represents current best practices. It is possible to enable guidance, while preventing specific guidance messages, by providing a list of item tokens, representing the class of guidance to be suppressed. In this way, unwanted advice can be suppressed without losing the benefit of other guidance. Unrecognized item tokens are quietly ignored by ld, allowing a given ld command line to be executed on a variety of older or newer versions of Solaris. The guidance offered by the current version of ld, and the item tokens used to disable these messages, are as follows. Specify Required Dependencies Dynamic executables and shared objects should explicitly define all of the dependencies they require. Guidance recommends the use of the -z defs option, should any symbol references remain unsatisfied when building dynamic objects. This guidance can be disabled with -z guidance=nodefs. Do Not Specify Non-Required Dependencies Dynamic executables and shared objects should not define any dependencies that do not satisfy the symbol references made by the dynamic object. Guidance recommends that unused dependencies be removed. This guidance can be disabled with -z guidance=nounused. Lazy Loading Dependencies should be identified for lazy loading. Guidance recommends the use of the -z lazyload option should any dependency be processed before either a -z lazyload or -z nolazyload option is encountered. This guidance can be disabled with -z guidance=nolazyload. Direct Bindings Dependencies should be referenced with direct bindings. Guidance recommends the use of the -B direct, or -z direct options should any dependency be processed before either of these options, or the -z nodirect option is encountered. This guidance can be disabled with -z guidance=nodirect. Pure Text Segment Dynamic objects should not contain relocations to non-writable, allocable sections. Guidance recommends compiling objects with Position Independent Code (PIC) should any relocations against the text segment remain, and neither the -z textwarn or -z textoff options are encountered. This guidance can be disabled with -z guidance=notext. Mapfile Syntax All mapfiles should use the version 2 mapfile syntax. Guidance recommends the use of the version 2 syntax should any mapfiles be encountered that use the version 1 syntax. This guidance can be disabled with -z guidance=nomapfile. Library Search Path Inappropriate dependencies that are encountered by ld are quietly ignored. For example, a 32-bit dependency that is encountered when generating a 64-bit object is ignored. These dependencies can result from incorrect search path settings, such as supplying an incorrect -L option. Although benign, this dependency processing is wasteful, and might hide a build problem that should be solved. Guidance recommends the removal of any inappropriate dependencies. This guidance can be disabled with -z guidance=nolibpath. In addition, -z guidance=noall can be used to entirely disable the guidance feature. See Chapter 7, Link-Editor Quick Reference, in the Linker and Libraries Guide for more information on guidance and advice for building better objects. Example The following example demonstrates how the guidance feature is intended to work. We will build a shared object that has a variety of shortcomings: Does not specify all it's dependencies Specifies dependencies it does not use Does not use direct bindings Uses a version 1 mapfile Contains relocations to the readonly allocable text (not PIC) This scenario is sadly very common — many shared objects have one or more of these issues. % cat hello.c #include <stdio.h> #include <unistd.h> void hello(void) { printf("hello user %d\n", getpid()); } % cat mapfile.v1 # This version 1 mapfile will trigger a guidance message % cc hello.c -o hello.so -G -M mapfile.v1 -lelf As you can see, the operation completes without error, resulting in a usable object. However, turning on guidance reveals a number of things that could be better: % cc hello.c -o hello.so -G -M mapfile.v1 -lelf -zguidance ld: guidance: version 2 mapfile syntax recommended: mapfile.v1 ld: guidance: -z lazyload option recommended before first dependency ld: guidance: -B direct or -z direct option recommended before first dependency Undefined first referenced symbol in file getpid hello.o (symbol belongs to implicit dependency /lib/libc.so.1) printf hello.o (symbol belongs to implicit dependency /lib/libc.so.1) ld: warning: symbol referencing errors ld: guidance: -z defs option recommended for shared objects ld: guidance: removal of unused dependency recommended: libelf.so.1 warning: Text relocation remains referenced against symbol offset in file .rodata1 (section) 0xa hello.o getpid 0x4 hello.o printf 0xf hello.o ld: guidance: position independent (PIC) code recommended for shared objects ld: guidance: see ld(1) -z guidance for more information Given the explicit advice in the above guidance messages, it is relatively easy to modify the example to do the right things: % cat mapfile.v2 # This version 2 mapfile will not trigger a guidance message $mapfile_version 2 % cc hello.c -o hello.so -Kpic -G -Bdirect -M mapfile.v2 -lc -zguidance There are situations in which the guidance does not fit the object being built. For instance, you want to build an object without direct bindings: % cc -Kpic hello.c -o hello.so -G -M mapfile.v2 -lc -zguidance ld: guidance: -B direct or -z direct option recommended before first dependency ld: guidance: see ld(1) -z guidance for more information It is easy to disable that specific guidance warning without losing the overall benefit from allowing the remainder of the guidance feature to operate: % cc -Kpic hello.c -o hello.so -G -M mapfile.v2 -lc -zguidance=nodirect Conclusions The linking guidelines enforced by the ld guidance feature correspond rather directly to our standards for building the core Solaris OS. I'm sure that comes as no surprise. It only makes sense that we would want to build our own product as well as we know how. Solaris is usually the first significant test for any new linker feature. We now enable guidance by default for all builds, and the effect has been very positive. Guidance helps us find suboptimal objects more quickly. Programmers get concrete advice for what to change instead of vague generalities. Even in the cases where we override the guidance, the makefile rules to do so serve as documentation of the fact. Deciding to use guidance is likely to cause some up front work for most code, as it forces you to consider using new features such as direct bindings. Such investigation is worthwhile, but does not come for free. However, the guidance suggestions offer a structured and straightforward way to tackle modernizing your objects, and once that work is done, for keeping them that way. The investment is often worth it, and will replay you in terms of better performance and fewer problems. I hope that you find guidance to be as useful as we have.

  Read the article

• Internal Mutation of Persistent Data Structures

  - by Greg Ros

  To clarify, when I mean use the terms persistent and immutable on a data structure, I mean that: The state of the data structure remains unchanged for its lifetime. It always holds the same data, and the same operations always produce the same results. The data structure allows Add, Remove, and similar methods that return new objects of its kind, modified as instructed, that may or may not share some of the data of the original object. However, while a data structure may seem to the user as persistent, it may do other things under the hood. To be sure, all data structures are, internally, at least somewhere, based on mutable storage. If I were to base a persistent vector on an array, and copy it whenever Add is invoked, it would still be persistent, as long as I modify only locally created arrays. However, sometimes, you can greatly increase performance by mutating a data structure under the hood. In more, say, insidious, dangerous, and destructive ways. Ways that might leave the abstraction untouched, not letting the user know anything has changed about the data structure, but being critical in the implementation level. For example, let's say that we have a class called ArrayVector implemented using an array. Whenever you invoke Add, you get a ArrayVector build on top of a newly allocated array that has an additional item. A sequence of such updates will involve n array copies and allocations. Here is an illustration: However, let's say we implement a lazy mechanism that stores all sorts of updates -- such as Add, Set, and others in a queue. In this case, each update requires constant time (adding an item to a queue), and no array allocation is involved. When a user tries to get an item in the array, all the queued modifications are applied under the hood, requiring a single array allocation and copy (since we know exactly what data the final array will hold, and how big it will be). Future get operations will be performed on an empty cache, so they will take a single operation. But in order to implement this, we need to 'switch' or mutate the internal array to the new one, and empty the cache -- a very dangerous action. However, considering that in many circumstances (most updates are going to occur in sequence, after all), this can save a lot of time and memory, it might be worth it -- you will need to ensure exclusive access to the internal state, of course. This isn't a question about the efficacy of such a data structure. It's a more general question. Is it ever acceptable to mutate the internal state of a supposedly persistent or immutable object in destructive and dangerous ways? Does performance justify it? Would you still be able to call it immutable? Oh, and could you implement this sort of laziness without mutating the data structure in the specified fashion?

  Read the article

• Silverlight Cream for December 08, 2010 -- #1005

  - by Dave Campbell

  In this Issue: Peter Kuhn, David Anson, Jesse Liberty, Mike Taulty(-2-, -3-), Kunal Chowdhury, Jeremy Likness, Martin Krüger, Beth Massi(-2-, -3-)/ Above the Fold: Silverlight: "Rebuilding the PDC 2010 Silverlight Application (Part 1)" Mike Taulty WP7: "WP7: Glossy text block custom control" Martin Krüger Lightswitch: "How to Create a Screen with Multiple Search Parameters in LightSwitch" Beth Massi From SilverlightCream.com: Requirements of and pitfalls in Windows Phone 7 serialization Peter Kuhn discusses Data Contract Serializer issuses on WP7 and how to work around them. Managed implementation of CRC32 and MD5 algorithms updated; new release of ComputeFileHashes for Silverlight, WPF, and the command-line! David Anson ties up some loose ends from a prior post on hash functions, and updates his CRC32 and MD5 algorithms. Windows Phone From Scratch #9 – Visual State Jesse Liberty's latest Windows Phone from Scratch tutorial up... and is on the Visual State... he extends a Button and codes up the State Transitions. Rebuilding the PDC 2010 Silverlight Application (Part 1) Mike Taulty has taken the time to rebuild the PDC2010 Silverlight App that folks wanted the source for... and he's taking multiple posts to explain the heck out of it. This first one is mostly infrastructure. Rebuilding the PDC 2010 Silverlight Application (Part 2) In the 2nd post of the series, Mike Taulty is handling the In/Out of Browser business because he eventually is going to be going OOB. Rebuilding the PDC 2010 Silverlight Application (Part 3) Part 3 finds Mike Taulty delving into WCF Data Services and getting some data on the screen. Paginating Records in Silverlight DataGrid using PagedCollectionView Kunal Chowdhury continues with his investigation of the PagedCollectionView with this post on Pagination of your data. Old School Silverlight Effects If you haven't seen Jeremy Likness' 'Old School' Effects page yet, go just for the entertainment... you'll find yourself hanging around for the code :) WP7: Glossy text block custom control Martin Krüger's latest post is a very cool custom control for WP7 that displays Glossy text... it ain't Metro, but it looks pretty nice... some of it almost like etched text. How to Create a Screen with Multiple Search Parameters in LightSwitch Looks like Beth Massi got a few Lightswitch posts in while I wasn't looking. First up is this one on a multiple-parameter search screen. Adding Static Images and Logos to LightSwitch Applications In the 2nd post, Beth Massi shows how to add your own static images and logos to Lightswitch apps... in response to reader questions. Getting the Most out of LightSwitch Summary Properties In her latest post, Beth Massi explains what Summary Properties are in Lightswitch and how to use them to get the best results for your users. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

  Read the article

• Good university for computer science with plans for game development

  - by DukeYore

  I am starting my computer science degree at a local community college in programming using C++. However, I will be transferring to a 4-year university. Does anyone have any insight on university programs? I know Cal State Fullerton has a degree with a minor in Game Development. however, is that as important as getting a degree from a really great school? If I could shoot for something like Cal Poly would that be better? Or even Stanford or SF State being so close to so many gaming companies up there in the Bay area? Thank you in advance for any guidance.

  Read the article

• Commandline Purge in AS11

  - by Dheeraj Kumar

  AS11 - B2B offering consists of numerous features that have been made available via commandline approach. Most of these are supplement to the already available User Interface based approach. One such is purging of runtime data. The commandline purge option enables the users to purge the runtime data, based on various criteria. This is an ANT based command, provides the flexibility to selectively set the criteria to purge the runtime data. Providing the command line option also enables the administrator to purge in bulk, without visiting the B2B UI, which can also be used for automation purpose By default archival is turned on for purge activity. As a pre-requisite, the respective folder needs to be configured in database with the proper permission. When no filename is provided for archived data, the sysdate will be considered for filename. Below are the various options to purge the runtime data Normal 0 Option ANT option   Message state -Dmsgstate   Date range -Dfromdate,  -Dtodate Format : dd/mm/yyyy hh:mm AM/PM Trading partner -Dtp   Direction -Ddirection   Message Type -Dmsgtype   Agreement Name -Dagreement   IdType/ value -Didtype,  -Didvalue   Archive -Darchive True/false By default true Archive file name -Darchivename File name (optional), will be used when archive is set to true. Normal 0 Note: When using -Darchivename the value must be a unique file name. An existing file name used with -Darchivename throws an exception v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} Normal 0 Below are the few of ant commands and various options.   Purge based on date range and message state: Normal 0 ant -f ant-b2b-util.xml b2bpurge -Dmode=RT -Dfromdate="19/12/2009 1:04 AM" -Dtodate="19/12/2009 1:05 AM" -Dmsgstate=MSG_COMPLETE -Darchivename="filename.dmp"  Purge based on direction: Normal 0 ant -f ant-b2b-util.xml b2bpurge -Dmode=RT -Ddirection="OUTBOUND" Normal 0 Purge based on agreement Name: Normal 0 ant -f ant-b2b-util.xml b2bpurge -Dmode=RT -Dagreement="agreement_name" Normal 0 Purge based on Trading partner Name: Normal 0 ant -f ant-b2b-util.xml b2bpurge -Dmode=RT -Dtp=GlobalChips Normal 0 Purge based on Message State: Normal 0 ant -f ant-b2b-util.xml b2bpurge -Dmode=RT -Dmsgstate="MSG_COMPLETE" Normal 0 ant -f ant-b2b-util.xml b2bpurge -Dmode=RT -Ddirection="OUTBOUND" -Dmsgstate="MSG_COMPLETE"

  Read the article

• Designing for an algorithm that reports progress

  - by Stefano Borini

  I have an iterative algorithm and I want to print the progress. However, I may also want it not to print any information, or to print it in a different way, or do other logic. In an object oriented language, I would perform the following solutions: Solution 1: virtual method have the algorithm class MyAlgoClass which implements the algo. The class also implements a virtual reportIteration(iterInfo) method which is empty and can be reimplemented. Subclass the MyAlgoClass and override reportIteration so that it does what it needs to do. This solution allows you to carry additional information (for example, the file unit) in the reimplemented class. I don't like this method because it clumps together two functionalities that may be unrelated, but in GUI apps it may be ok. Solution 2: observer pattern the algorithm class has a register(Observer) method, keeps a list of the registered observers and takes care of calling notify() on each of them. Observer::notify() needs a way to get the information from the Subject, so it either has two parameters, one with the Subject and the other with the data the Subject may pass, or just the Subject and the Observer is now in charge of querying it to fetch the relevant information. Solution 3: callbacks I tend to see the callback method as a lightweight observer. Instead of passing an object, you pass a callback, which may be a plain function, but also an instance method in those languages that allow it (for example, in python you can because passing an instance method will remain bound to the instance). C++ however does not allow it, because if you pass a pointer to an instance method, this will not be defined. Please correct me on this regard, my C++ is quite old. The problem with callbacks is that generally you have to pass them together with the data you want the callback to be invoked with. Callbacks don't store state, so you have to pass both the callback and the state to the Subject in order to find it at callback execution, together with any additional data the Subject may provide about the event is reporting. Question My question is relative to the fact that I need to implement the opening problem in a language that is not object oriented, namely Fortran 95, and I am fighting with my usual reasoning which is based on python assumptions and style. I think that in Fortran the concept is similar to C, with the additional trouble that in C you can store a function pointer, while in Fortran 95 you can only pass it around. Do you have any comments, suggestions, tips, and quirks on this regard (in C, C++, Fortran and python, but also in any other language, so to have a comparison of language features that can be exploited on this regard) on how to design for an algorithm that must report progress to some external entity, using state from both the algorithm and the external entity ?

  Read the article

• Building a database class in PHP

  - by Sprottenwels

  I wonder if I should write a database class for my application, and if so, how to accomplish it? Over there on SO, a guy mentioned it should be written as an abstract class. However, I can't understand why this would be a benefit. Do I understand correctly, that if I would write an abstract class, every other class that methods will need a database connection, could simply extend this abstract class and have it's own database object? If so, how is this different from a "normal" class where I could instantiate an database object? Another method would be to completely forget about my own class and to instantiate a mysqli object on demand. What do you recommend?

  Read the article

• Problem using glm::lookat

  - by omikun

  I am trying to rotate a sprite so it is always facing a 3D camera. Object GLfloat vertexData[] = { // X Y Z U V 0.0f, 0.8f, 0.0f, 0.5f, 1.0f, -0.8f,-0.8f, 0.0f, 0.0f, 0.0f, 0.8f,-0.8f, 0.0f, 1.0f, 0.0f, }; Per frame transform glm::mat4 newTransform = glm::lookAt(glm::vec3(0), gCamera.position(), gCamera.up()); shaders->setUniform("camera", gCamera.matrix()); shaders->setUniform("model", newTransform); In the vertex shader: gl_Position = camera * model * vec4(vert, 1); The object will track the camera if I move the camera up or down, but if I move the camera left/right (spin the camera around the object's y axis), it will rotate in the other direction so I end up seeing its front twice and its back twice as I rotate around it 360. If I use -gCamera.up() instead, it would track the camera side to side, but spin the opposite direction when I move the camera up/down. What am I doing wrong?

  Read the article

• Clean way to use mutable implementation of Immutable interfaces for encapsulation

  - by dsollen

  My code is working on some compost relationship which creates a tree structure, class A has many children of type B, which has many children of type C etc. The lowest level class, call it bar, also points to a connected bar class. This effectively makes nearly every object in my domain inter-connected. Immutable objects would be problematic due to the expense of rebuilding almost all of my domain to make a single change to one class. I chose to go with an interface approach. Every object has an Immutable interface which only publishes the getter methods. I have controller objects which constructs the domain objects and thus has reference to the full objects, thus capable of calling the setter methods; but only ever publishes the immutable interface. Any change requested will go through the controller. So something like this: public interface ImmutableFoo{ public Bar getBar(); public Location getLocation(); } public class Foo implements ImmutableFoo{ private Bar bar; private Location location; @Override public Bar getBar(){ return Bar; } public void setBar(Bar bar){ this.bar=bar; } @Override public Location getLocation(){ return Location; } } public class Controller{ Private Map<Location, Foo> fooMap; public ImmutableFoo addBar(Bar bar){ Foo foo=fooMap.get(bar.getLocation()); if(foo!=null) foo.addBar(bar); return foo; } } I felt the basic approach seems sensible, however, when I speak to others they always seem to have trouble envisioning what I'm describing, which leaves me concerned that I may have a larger design issue then I'm aware of. Is it problematic to have domain objects so tightly coupled, or to use the quasi-mutable approach to modifying them? Assuming that the design approach itself isn't inherently flawed the particular discussion which left me wondering about my approach had to do with the presence of business logic in the domain objects. Currently I have my setter methods in the mutable objects do error checking and all other logic required to verify and make a change to the object. It was suggested that this should be pulled out into a service class, which applies all the business logic, to simplify my domain objects. I understand the advantage in mocking/testing and general separation of logic into two classes. However, with a service method/object It seems I loose some of the advantage of polymorphism, I can't override a base class to add in new error checking or business logic. It seems, if my polymorphic classes were complicated enough, I would end up with a service method that has to check a dozen flags to decide what error checking and business logic applies. So, for example, if I wanted to have a childFoo which also had a size field which should be compared to bar before adding par my current approach would look something like this. public class Foo implements ImmutableFoo{ public void addBar(Bar bar){ if(!getLocation().equals(bar.getLocation()) throw new LocationException(); this.bar=bar; } } public interface ImmutableChildFoo extends ImmutableFoo{ public int getSize(); } public ChildFoo extends Foo implements ImmutableChildFoo{ private int size; @Override public int getSize(){ return size; } @Override public void addBar(Bar bar){ if(getSize()<bar.getSize()){ throw new LocationException(); super.addBar(bar); } My colleague was suggesting instead having a service object that looks something like this (over simplified, the 'service' object would likely be more complex). public interface ImmutableFoo{ ///original interface, presumably used in other methods public Location getLocation(); public boolean isChildFoo(); } public interface ImmutableSizedFoo implements ImmutableFoo{ public int getSize(); } public class Foo implements ImmutableSizedFoo{ public Bar bar; @Override public void addBar(Bar bar){ this.bar=bar; } @Override public int getSize(){ //default size if no size is known return 0; } @Override public boolean isChildFoo return false; } } public ChildFoo extends Foo{ private int size; @Override public int getSize(){ return size; } @Override public boolean isChildFoo(); return true; } } public class Controller{ Private Map<Location, Foo> fooMap; public ImmutableSizedFoo addBar(Bar bar){ Foo foo=fooMap.get(bar.getLocation()); service.addBarToFoo(foo, bar); returned foo; } public class Service{ public static void addBarToFoo(Foo foo, Bar bar){ if(foo==null) return; if(!foo.getLocation().equals(bar.getLocation())) throw new LocationException(); if(foo.isChildFoo() && foo.getSize()<bar.getSize()) throw new LocationException(); foo.setBar(bar); } } } Is the recommended approach of using services and inversion of control inherently superior, or superior in certain cases, to overriding methods directly? If so is there a good way to go with the service approach while not loosing the power of polymorphism to override some of the behavior?

  Read the article

• Immutable Method in Java

  - by Chris Okyen

  In Java, there is the final keyword in lieu of the const keyword in C and C++. In the latter languages there are mutable and immutable methods such as stated in the answer by Johannes Schaub - litb to the question How many and which are the uses of “const” in C++? Use const to tell others methods won't change the logical state of this object. struct SmartPtr { int getCopies() const { return mCopiesMade; } }ptr1; ... int var = ptr.getCopies(); // returns mCopiesMade and is specified that to not modify objects state. How is this performed in Java?

  Read the article

• How do I get wireless working on a Dell Inspiron 510m?

  - by user17449

  Why WiFi don't work in my Dell Inspiron 510m with Ubuntu 10.04? Is that usefull? inspiron@Inspiron:~$ rfkill list all inspiron@Inspiron:~$ sudo lshw -C network [sudo] password for inspiron: *-network:0 DISABLED description: Wireless interface product: PRO/Wireless LAN 2100 3B Mini PCI Adapter vendor: Intel Corporation physical id: 3 bus info: pci@0000:01:03.0 logical name: eth1 version: 04 serial: 00:0c:f1:5b:5d:40 width: 32 bits clock: 33MHz capabilities: pm bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=ipw2100 driverversion=git-1.2.2 firmware=712.0.3:3:00000001 latency=32 link=no maxlatency=34 mingnt=2 multicast=yes wireless=unassociated resources: irq:5 memory:fcffe000-fcffefff *-network:1 description: Ethernet interface product: 82801DB PRO/100 VE (MOB) Ethernet Controller vendor: Intel Corporation physical id: 8 bus info: pci@0000:01:08.0 logical name: eth0 version: 81 serial: 00:11:43:41:d8:b8 size: 10MB/s capacity: 100MB/s width: 32 bits clock: 33MHz capabilities: pm bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=e100 driverversion=3.5.24-k2-NAPI duplex=half firmware=N/A ip=192.168.0.2 latency=32 link=no maxlatency=56 mingnt=8 multicast=yes port=MII speed=10MB/s resources: irq:11 memory:fcffd000-fcffdfff ioport:ecc0(size=64) inspiron@Inspiron:~$ iwconfig wlan0 wlan0 No such device inspiron@Inspiron:~$ ifconfig -a eth0 Link encap:Ethernet Endereço de HW 00:11:43:41:d8:b8 inet end.: 192.168.0.2 Bcast:192.168.0.255 Masc:255.255.255.0 UP BROADCAST MULTICAST MTU:1500 Métrica:1 pacotes RX:0 erros:0 descartados:0 excesso:0 quadro:0 Pacotes TX:0 erros:0 descartados:0 excesso:0 portadora:0 colisões:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) eth1 Link encap:Ethernet Endereço de HW 00:0c:f1:5b:5d:40 BROADCAST MULTICAST MTU:1500 Métrica:1 pacotes RX:0 erros:0 descartados:0 excesso:0 quadro:0 Pacotes TX:0 erros:0 descartados:0 excesso:0 portadora:0 colisões:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) IRQ:5 Endereço de E/S:0xe000 Memória:fcffe000-fcffefff lo Link encap:Loopback Local inet end.: 127.0.0.1 Masc:255.0.0.0 endereço inet6: ::1/128 Escopo:Máquina UP LOOPBACK RUNNING MTU:16436 Métrica:1 pacotes RX:628 erros:0 descartados:0 excesso:0 quadro:0 Pacotes TX:628 erros:0 descartados:0 excesso:0 portadora:0 colisões:0 txqueuelen:0 RX bytes:50104 (50.1 KB) TX bytes:50104 (50.1 KB) inspiron@Inspiron:~$ nm-tool NetworkManager Tool State: connected - Device: eth1 ----------------------------------------------------------------- Type: 802.11 WiFi Driver: ipw2100 State: unavailable Default: no HW Address: 00:0C:F1:5B:5D:40 Capabilities: Wireless Properties WEP Encryption: yes WPA Encryption: yes WPA2 Encryption: yes Wireless Access Points - Device: eth0 ----------------------------------------------------------------- Type: Wired Driver: e100 State: unmanaged Default: no HW Address: 00:11:43:41:D8:B8 Capabilities: Carrier Detect: yes Speed: 10 Mb/s Wired Properties Carrier: off inspiron@Inspiron:~$

  Read the article

• android: How to apply pinch zoom and pan to 2D GLSurfaceView

  - by mak_just4anything

  I want to apply pinch zoom and panning effect on GLSurfaceView. It is Image editor, so It would not be 3D object. I tried to implement using these following links: https://groups.google.com/forum/#!topic/android-developers/EVNRDNInVRU Want to apply pinch and zoom to GLSurfaceView(3d Object) http://www.learnopengles.com/android-lesson-one-getting-started/ These all are links for 3D object rendering. I can not use ImageView as I need to work out with OpenGL so, had to implement it on GLSurfaceView. Suggest me or any reference links are there for such implementation. **I need it for 2D only.

  Read the article

• Design Pattern for Complex Data Modeling

  - by Aaron Hayman

  I'm developing a program that has a SQL database as a backing store. As a very broad description, the program itself allows a user to generate records in any number of user-defined tables and make connections between them. As for specs: Any record generated must be able to be connected to any other record in any other user table (excluding itself...the record, not the table). These "connections" are directional, and the list of connections a record has is user ordered. Moreover, a record must "know" of connections made from it to others as well as connections made to it from others. The connections are kind of the point of this program, so there is a strong possibility that the number of connections made is very high, especially if the user is using the software as intended. A record's field can also include aggregate information from it's connections (like obtaining average, sum, etc) that must be updated on change from another record it's connected to. To conserve memory, only relevant information must be loaded at any one time (can't load the entire database in memory at load and go from there). I cannot assume the backing store is local. Right now it is, but eventually this program will include syncing to a remote db. Neither the user tables, connections or records are known at design time as they are user generated. I've spent a lot of time trying to figure out how to design the backing store and the object model to best fit these specs. In my first design attempt on this, I had one object managing all a table's records and connections. I attempted this first because it kept the memory footprint smaller (records and connections were simple dicts), but maintaining aggregate and link information between tables became....onerous (ie...a huge spaghettified mess). Tracing dependencies using this method almost became impossible. Instead, I've settled on a distributed graph model where each record and connection is 'aware' of what's around it by managing it own data and connections to other records. Doing this increases my memory footprint but also let me create a faulting system so connections/records aren't loaded into memory until they're needed. It's also much easier to code: trace dependencies, eliminate cycling recursive updates, etc. My biggest problem is storing/loading the connections. I'm not happy with any of my current solutions/ideas so I wanted to ask and see if anybody else has any ideas of how this should be structured. Connections are fairly simple. They contain: fromRecordID, fromTableID, fromRecordOrder, toRecordID, toTableID, toRecordOrder. Here's what I've come up with so far: Store all the connections in one big table. If I do this, either I load all connections at once (one big db call) or make a call every time a user table is loaded. The big issue here: the size of the connections table has the potential to be huge, and I'm afraid it would slow things down. Store in separate tables all the outgoing connections for each user table. This is probably the worst idea I've had. Now my connections are 'spread out' over multiple tables (one for each user table), which means I have to make a separate DB called to each table (or make a huge join) just to find all the incoming connections for a particular user table. I've avoided making "one big ass table", but I'm not sure the cost is worth it. Store in separate tables all outgoing AND incoming connections for each user table (using a flag to distinguish between incoming vs outgoing). This is the idea I'm leaning towards, but it will essentially double the total DB storage for all the connections (as each connection will be stored in two tables). It also means I have to make sure connection information is kept in sync in both places. This is obviously not ideal but it does mean that when I load a user table, I only need to load one 'connection' table and have all the information I need. This also presents a separate problem, that of connection object creation. Since each user table has a list of all connections, there are two opportunities for a connection object to be made. However, connections objects (designed to facilitate communication between records) should only be created once. This means I'll have to devise a common caching/factory object to make sure only one connection object is made per connection. Does anybody have any ideas of a better way to do this? Once I've committed to a particular design pattern I'm pretty much stuck with it, so I want to make sure I've come up with the best one possible.

  Read the article

• Best way to store a large amount of game objects and update the ones onscreen

  - by user3002473

  Good afternoon guys! I'm a young beginner game developer working on my first large scale game project and I've run into a situation where I'm not quite sure what the best solution may be (if there is a lone solution). The question may be vague (if anyone can think of a better title after having read the question, please edit it) or broad but I'm not quite sure what to do and I thought it would help just to discuss the problem with people more educated in the field. Before we get started, here are some of the questions I've looked at for help in the past: Best way to keep track of game objects Elegant way to simulate large amounts of entities within a game world What is the most efficient container to store dynamic game objects in? I've also read articles about different data structures commonly used in games to store game objects such as this one about slot maps, but none of them are really what I'm looking for. Also, if it helps at all I'm using Python 3 to design the game. It has to be Python 3, if I could I would use C++ or Unityscript or something else, but I'm restricted to having to use Python 3. My game will be a form of side scroller shooter game. In said game the player will traverse large rooms with large amounts of enemies and other game objects to update (think some of the larger areas in Cave Story or Iji). The player obviously can't see the entire room all at once, so there is a viewport that follows the player around and renders only a selection of the room and the game objects that it contains. This is not a foreign concept. The part that's getting me confused has to do with how certain game objects are updated. Some of them are to be updated constantly, regardless of whether or not they can be seen. Other objects however are only to be updated when they are onscreen (for example, an enemy would only be updated to react to the player when it is onscreen or when it is in a certain range of the screen). Another problem is that game objects have to be easily referable by other game objects; something that happens in the player's update() method may affect another object in the world. Collision detection in games is always a serious problem. I need a way of containing the game objects such that it minimizes the number of cases when testing for collisions against one another. The final problem is that of creating and destroying game objects. I think this problem is pretty self explanatory. To store the game objects then I've considered a number of different methods. The original method I had was to simply store all the objects in a hash table by an id. This method was simple, and decently fast as it allows all the objects to be looked up in O(1) complexity, and also allows them to be deleted fairly easily. Hash collisions would not be a major problem; I wasn't originally planning on using computer generated ids to store the game objects I was going to rely on them all using ids given to them by the game designer (such names would be strings like 'Player' or 'EnemyWeapon4'), and even if I did use computer generated ids, if I used a decent hashing algorithm then the chances of collisions would be around 1 in 4 billion. The problem with using a hash table however is that it is inefficient in checking to see what objects are in range of the viewport. Considering the fact that certain game objects move (as well as the viewport itself), the only solution I could think of in order to only update objects that are in the viewport would be to iterate through every object in the hash table and check if it is in the viewport or not, updating only the ones that are in the valid area. This would be incredibly slow in scenarios where the amount of game objects exceeds 500, or even 200. The second solution was to store everything in a 2-d list. The world is partitioned up into cells (a tilemap essentially), where each cell or tile is the same size and is square. Each cell would contain a list of the game objects that are currently occupying it (each game object would be inserted into a cell depending on the center of the object's collision mask). A 2-d list would allow me to take the top-left and bottom-right corners of the viewport and easily grab a rectangular area of the grid containing only the cells containing entities that are in valid range to be updated. This method also solves the problem of collision detection; when I take an entity I can find the cell that it is currently in, then check only against entities in it's cell and the 8 cells around it. One problem with this system however is that it prohibits easy lookup of game objects. One solution I had would be to simultaneously keep a hash table that would contain all the positions of the objects in the 2-d list indexed by the id of said object. The major problem with a 2-d list is that it would need to be rebuilt every single game frame (along with the hash table of object positions), which may be a serious detriment to game speed. Both systems have ups and downs and seem to solve some of each other's problems, however using them both together doesn't seem like the best solution either. If anyone has any thoughts, ideas, suggestions, comments, opinions or solutions on new data structures or better implementations of the existing data structures I have in mind, please post, any and all criticism and help is welcome. Thanks in advance! EDIT: Please don't close the question because it has a bad title, I'm just bad with names!

  Read the article

< Previous Page | 349 350 351 352 353 354 355 356 357 358 359 360  | Next Page >