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  • Which is the best and appropriate way to write the code in Winforms ?

    - by Harikrishna
    What is the best way to write the code ? (1) Like directly writing the code in the button_click() event. or (2) Make the function of that code which I write in button_click() event and write this function in one class and then that function I should call in the button_Click() event.Like is it called three-tired approach to write the code ? Like in button_Click() event I write the code to save the records in csv file from datatable.So I should write that code in button_Click() event or I should make one new function and one new class and write that code in that function which is the new class and calling that function in button_Click() event. This is only one example but I am talking about all the code written in my application that which is the appropriate and best way to write the code and what are the benefits ? Note that I write the code in Winforms with c#.

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  • What is the best, python or bash for selectively concatenating lots of files?

    - by Werner
    Hi, I have around 20000 files coming from the output of some program, and their names follow the format: data1.txt data2.txt ... data99.txt data100.txt ... data999.txt data1000.txt ... data20000.txt I would like to write a script that gets as input argument the number N. Then it makes blocks of N concatenated files, so if N=5, it would make the following new files: data_new_1.txt: it would contain (concatenated) data1.txt to data5.txt (like cat data1.txt data2.txt ... data_new_1.txt ) data_new_2.txt: it would contain (concatenated) data6.txt to data10.txt ..... I wonder what do you think would be the best approach to do this, whether bash, python or another one like awk, perl, etc. The best approach I mean in terms of simplest code. Thanks

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  • best method in jquery for replacing rows in a table after server side processing such as mysql sorti

    - by Kevin J
    What is the 'best practice' when returning dynamic data for a table (server side sorting, filtering etc from a db) ? Do you return just the data in json, and repeatedly clone a row element, replacing the values in each row (thus decreasing the size of the ajax call, but increasing the client side processing), or return the full html, and replace with .html or .append? Or is there another method I'm missing? This is a frequent situation in my app, and in some cases a bottleneck, and I am unsure if what I am doing is the best solution. Currently, I return the row html and use a single .append call, after emptying all the rows except the header.

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  • What is the best way to programmatically run javascript when an ASP.net page loads?

    - by Rising Star
    In my global.asax file for my ASP.net project, I am checking for certain conditions. When those conditions are met, I want to automatically execute javascript code when the page runs. This is my code: if condition Then Response.Write("") Response.Write(" // Javascript code to do stuff ") Response.Write("") End If While this appears to work to execute the Javascript code, I don't think it's a best practice because this code will preceed all of the HTML of the page that gets loaded. What is the best way of programmatically tacking on some extra Javascript code to be run when my page loads?

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  • Best practices for storing & selecting time/date with php & mysql?

    - by Adam
    I often find myself storing data in a mysql database, and then wanting to display all sorts of stats about my data, specifically stuff like 'how many rows do I have for this date, or that date'. Does anyone know of (or could write) a good tutorial on this subject? Ideally a good tutorial would overview: Best practices when storing the data (i.e. what formats to use, how to use them servertime vs. generated time, etc.) Best practices when selecting data from the database with php (i.e. how to sort rows by date, how to retrieve only rows from a certain date, or a certain hour, etc).. Timezones and other issues that might come up. Thanks in advance.

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  • [Python] Best strategy for dealing with incomplete lines of data from a file.

    - by adoran
    I use the following block of code to read lines out of a file 'f' into a nested list: for data in f: clean_data = data.rstrip() data = clean_data.split('\t') t += [data[0]] strmat += [data[1:]] Sometimes, however, the data is incomplete and a row may look like this: ['955.159', '62.8168', '', '', '', '', '', '', '', '', '', '', '', '', '', '29', '30', '0', '0'] It puts a spanner in the works because I would like Python to implicitly cast my list as floats but the empty fields '' cause it to be cast as an array of strings (dtype: s12). I could start a second 'if' statement and convert all empty fields into NULL (since 0 is wrong in this instance) but I was unsure whether this was best. Is this the best strategy of dealing with incomplete data? Should I edit the stream or do it post-hoc?

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  • Silverlight Cream for December 18, 2010 - 2 -- #1013

    - by Dave Campbell
    In this Issue: Michael Washington, Pete Brown, Robby Ingebretsen, Bill Reiss, Jordan Knight, Mike Taulty, Justin Angel, Jeff Blankenburg. Above the Fold: Silverlight: "Creating the Silverlight View Model (MVVM) Control: Calendar Icon" Michael Washington WP7: "United Nations News for Windows Phone 7" Justin Angel Silverlight, WP7/WPF: "CameraPanel: A Parallax Panel for Silverlight, WP7 or WPF" Robby Ingebretsen Shoutouts: Michael Scherotter produced a Silverlight Webcam photo app that he's providing as a free install: A Free Webcam Photo Application in Silverlight From SilverlightCream.com: Creating the Silverlight View Model (MVVM) Control: Calendar Icon Michael Washington has a stunning Calendar Control/Icon up on his blog... walking through how he built it and how you can easily use it in your Silverlight or WP7 app. Strategies for Improving INotifyPropertyChanged in WPF and Silverlight Pete Brown takes a look at INPC and some of the ways this is dealt with to avoid some of the tedius code-reuse errors we all make. CameraPanel: A Parallax Panel for Silverlight, WP7 or WPF Robby Ingebretsen gives up the code for that cool panel he's got on his homepage where the small panels move about seemingly in space. Writing a Windows Phone 7 game? Have a fallback plan Bill Reiss, who has a great WP7 game up - Popper 2 - has a very well-thought-out post up about WP7 'indie' games and the future thereof... great comments from reader/authors as well Automatic template selection – marrying a view to a view model Jordan Knight has the 2nd post of his series on MVVM up... he's talking about it in context of their XamlingCore, but concepts are all good. Rebuilding the PDC 2010 Silverlight Application (Part 5) Mike Taulty's next episode in describing the development of the PDC10 app he wrote is up ... again lots of Blend goodness in this one where he's adding buttons to let the user (us) download whatever is available for the chosen session. United Nations News for Windows Phone 7 In a munificent gesture, Justin Angel not only made his United Nation News app free on the marketplace, but he's posted the source to CodePlex! Justin had sent me a XAP a couple weeks ago, but for some reason, I can no longer sideload so wasn't able to try it until now... too cool, Justin! What I Learned In WP7 – Issue #6 Jeff Blankenburg has his latest "What I learned in WP7" tip up ... and this is one about the marketplace written by someone that's been there and back a few times... 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

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  • Silverlight Cream for November 08, 2011 -- #1165

    - by Dave Campbell
    In this Issue: Brian Noyes, Michael Crump, WindowsPhoneGeek, Erno de Weerd, Jesse Liberty, Derik Whittaker, Sumit Dutta, Asim Sajjad, Dhananjay Kumar, Kunal Chowdhury, and Beth Massi. Above the Fold: Silverlight: "Working with Prism 4 Part 1: Getting Started" Brian Noyes WP7: "Getting Started with the Coding4Fun toolkit Tile Control" WindowsPhoneGeek LightSwitch: "How to Connect to and Diagram your SQL Express Database in Visual Studio LightSwitch" Beth Massi Shoutouts: Michael Palermo's latest Desert Mountain Developers is up Michael Washington's latest Visual Studio #LightSwitch Daily is up From SilverlightCream.com: Working with Prism 4 Part 1: Getting Started Brian Noyes has a series starting at SilverlightShow about Prism 4 ... this is the first one, so a good time to jump in and pick up on an intro and basic info about Prism plus building your first Prism app. 10 Laps around Silverlight 5 (Part 5 of 10) Michael Crump has Part 5 of his 10-part Silverlight 5 investigation up at SilverlightShow talking about all the various text features added in Silverlight 5 Beta: Text Tracking and Leading, Linked and MultiColumn, OpenType, etc. Getting Started with the Coding4Fun toolkit Tile Control WindowsPhoneGeek takes on the Tile control from the Coding4Fun toolkit... as usual, great tutorial... diagrams, code, explanation Using AppHarbor, Bitbucket and Mercurial with ASP.NET and Silverlight – Part 2 CouchDB, Cloudant and Hammock Erno de Weerd has Part 2 of his trilogy and he's trying to beat David Anson for the long title record :) ... in this episode, he's adding in cloud storage to the mix in a 35-step tutorial. Background Audio Jesse Liberty's talking about background Audio... and no not the Muzak in the elevator (do they still have that?) ... he's tlking about the WP7.1 BackgroundAudioPlayer Using the ToggleSwitch in WinRT/Metro (for C#) Derik Whittaker shows off the ToggleSwitch for WinRT/Metro... not a lot to be said about it, but he says it all :) Part 19 - Windows Phone 7 - Access Phone Contacts Sumit Dutta has Part 19! of his WP7 series up... talking today about getting a phone number from the directory using the PhoneNumberChooserTask ContextMenu using MVVM Asim Sajjad shows how to make the Context Menu ViewModel friendly in this short tutorial. Code to make call in Windows Phone 7 Dhananjay Kumar's latest WP7 post is explaining how to make a call programmatically using the PhoneCallTask launcher. Silverlight Page Navigation Framework - Basic Concept Kunal Chowdhury has a 3-part tutorial series on Silverlight Navigation up. This is the first in the series, and he hits the basics... what constitutes a Page, and how to get started with the navigation framework. How to Connect to and Diagram your SQL Express Database in Visual Studio LightSwitch Beth Massi's latest LightSwitch post is on using the Data Designer to easily crete and model database tables... during development this is in SQL Express, but can be deployed to most SQL server db you like 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

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  • Silverlight Cream for June 28, 2011 -- #1112

    - by Dave Campbell
    In this Issue: WindowsPhoneGeek, John Papa, Mike Taulty, Erno de Weerd, Stephen Price, Chris Rouw, Peter Kuhn, Damian Schenkelman, Michael Washington, and Manas Patnaik. Above the Fold: Silverlight: "Binding to View Model properties in Data Templates. The RootBinding Markup Extension" Damian Schenkelman WP7: "Storing Files in SQL Server using WCF RIA Services and Silverlight – Part 3" Chris Rouw LightSwitch: "Saving Files To File System With LightSwitch (Uploading Files)" Michael Washington Shoutouts: Steve Wortham announced a change to his XilverlightXAP.com site... they're now accepting XAML illustrations: Introducing XAML Illustrations, Increased Payouts to Contributors, and More Amid all the discussions that I've tried to avoid, Michael Washinton is Betting The House On LightSwitch From SilverlightCream.com: Dynamically updating a data bound LongListSelector in Windows Phone WindowsPhoneGeek's latest is on using the LongListSelector from the Toolkit and dynamically updating it with data... detailed guidelines and plenty of pictures and code as always. Silverlight TV 77: Exploring 3D with Aaron Oneal John Papa has Silverlight TV number 77 up and is chatting with Aaron Oneal, program manager of the Silverlight 3D efforts... too cool. Silverlight WebBrowser Control for Offline Apps (Part 2) Mike Taulty wrote this post in Silverlight 5 Beta, but says it should be fine in 4... a continuation of his HTML Content display using the WebBrowser control while offline Windows Phone 7: Databinding and the Pivot Control Erno de Weerd discusses the Pivot control in WP7 based on his attempts to use it in an app. Required Attribute on an Entity Stephen Price has a new post at XAML Source... first is this one on setting the required attribute and the troubles you can get into if it's not set correctly Storing Files in SQL Server using WCF RIA Services and Silverlight – Part 3 Chris Rouw has Part 3 of his series on Storing files in SQL Server using FILESTREAM Storage in SQL Server 2008 and Silverlight... this time he's viewing files stored in the FILESTREAM from the LOB app. Getting ready for the Windows Phone 7 Exam 70-599 (Part 4) Peter Kuhn has Part 4 of his series on getting ready for the WP7 exam up at SilverlightShow... the date is coming up soon... are you ready? Binding to View Model properties in Data Templates. The RootBinding Markup Extension Damian Schenkelman has a Silverlight 5 Beta post up... digging into the XAML Markup Extensions and popping out a RootBindingExtensionthat helps bind to a property in a view model from a DataTemplate. Saving Files To File System With LightSwitch (Uploading Files) Michael Washington has a cool tutorial up on his new LightSwitch Help Website... File Upload to a server file system using LightSwitch, plus a project to download... good stuff! Microsoft Media Platform (MMPPF): Player Framework for Silverlight Manas Patnaik's latest post is about the Media Player Project... some of the history of media with Silvelight and how to go about using the Media Player Project bits 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

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  • Vampires – Folklore, Fantasy, and Fact

    - by Akemi Iwaya
    Halloween is practically here, so what better time is there than now to look into the history of vampires? Michael Molina has put together a great presentation looking at the folklore and types of vampires throughout history, sorting facts from fiction, and more in the TED-Ed channel’s latest video. Vampires: Folklore, fantasy and fact – Michael Molina [YouTube]     

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  • Silverlight Cream for December 26, 2010 -- #1015

    - by Dave Campbell
    In this all-submittal Issue: Michael Washington(-2-), Ian T. Lackey(-2-, -3-), Sandrino Di Mattia, Colin Eberhardt(-2-), and Antoni Dol. Above the Fold: Silverlight: "A Style for the Silverlight CoverFlow Control Slider" Antoni Dol WP7: "Getting the right behaviors in your Phone 7 App – Part 1 Phone Home" (and the other two parts) Ian T. Lackey Silverlight/WPF: "A Simplified Grid Markup for Silverlight and WPF" Colin Eberhardt Shoutouts: Dennis Doomen has updated his Coding Guidelines and provided a new WhitePaper, A4 cheat sheet, and VS2010 rule sets: December Update of the Coding Guidelines for C# 3.0 and C# 4.0 From SilverlightCream.com: Windows Phone 7: Saving Data when Keyboard is visible MIchael Washington takes a possible desktop approach to a data-saving issue on WP7... good solution, and one of the commenters brought up another. Windows Phone 7 View Model (MVVM) ApplicationBar Since I'm catching up, there's another post by Michael Washington... this one is looking at the WP7 ApplicationBar, and issues if you're trying to stay MVVM-proper. Michael gets around that by creating the AppBar with a behavior, and shares with all of us! Getting the right behaviors in your Phone 7 App – Part 1 Phone Home Ian T. Lackey has begun a series where he's packaging common tasks into reusable behaviors. First up is a phone dialer launching action that can be dropped on any control in your app. Getting the right behaviors in your Phone 7 App – Part 2 Binding & Browsing In his next post, Ian T. Lackey digs into the WebBrowserTask and provides a behavior allowing you to launch a browser session straight to an URL from any WP7 control. Getting the right behaviors in your Phone 7 App – Part 3 Email ‘em In his last post (all in one day), Ian T. Lackey looks at EmailComposeTask, ending up with a behavior to pre-populate EmailAddress and Subject. Cracking a Microsoft contest or why Silverlight-WCF security is important Sandrino Di Mattia was working on an app while also having a page up for a MSDN/TechNet game, and noticed some interesting WCF traffic that he was easily able to get access to. A Simplified Grid Markup for Silverlight and WPF Colin Eberhardt built us all an attached property for the Grid control that bails us out from the ugly layout we always have to put into position... oh, also for WPF! #uksnow #silverlight The Movie! – Happy Christmas Colin Eberhardt also took some time to have fun with his Twitter/BingMaps mashup for the UKSnow hashtag... you can now playback the snowfall reports, and mouse-over the snowflakes to see the original tweet... very cool stuff, Colin! A Style for the Silverlight CoverFlow Control Slider Antoni Dol got tired of the Silverlight Slider in the CoverFlow control and crafted a very nice-looking style for the Slider ... check it out and grab the source. 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

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  • What's New with PeopleTools

    Michael Ni, Vice President of Product Strategy at Oracle, goes through with Cliff the PeopleTools Roadmap that was outlined at OOW, discusses what's in the latest release of PeopleTools and gives an overview of the new features that will be in the next few releases of PeopleTools. Michael also comments to Cliff about the next generation of applications, Fusion Architecture and the Total Ownership Experience (TOE) across the lifecycle of the applications.

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  • A Complete Customer Experience Solution (3 of 3 in 'No Customer Left Behind' Series)

    - by Kathryn Perry
    A guest post by David Vap, Group Vice President, Oracle Applications Product Development In my previous post, I talked about taking three concrete steps to improve your customers' overall experiences: 1) understand your customer, 2) empower your ecosystem, and 3) adapt your business. To do these effectively and efficiently, it's important to find the right technology that can bridge the gaps across your channels, interactions, departments, and repositories. Oracle has spent the past three years and more than six billion dollars acquiring and developing some of the world's best-of-breed applications. The result is the most comprehensive customer experience (CX) portfolio offering in the World - bar none: ATG Best in Class Selling Experiences Fatwire Best in Class Marketing Experiences Inquira Best in Class Support Experiences Endecca Best in Class Search Experiences RightNow Best in Class Service Experiences Vitrue & Involver Best in Class Social Marketing Collective Intellect Best In Class Social Listening We don't expect organizations to eat the CX elephant in one bite, nor should they try to. There are key strategic initiatives within each of the four main pillars of our customer experience offering for which we deliver solutions: 1. Customer Experience for Marketing Social Listening and Engagement Social Marketing Marketing Websites Demand Generation and Lead Management Marketing and Loyalty Management 2. Customer Experience for Commerce Search, Navigation & Content Delivery Cross-Channel Commerce Targeting & Product Recommendations Social Commerce Order Management & Fulfillment Retail Store Operations 3. Customer Experience for Sales Sales Force Automation Social Selling Territory & Quota Management Revenue Forecasting Partner Relationship Management Quote to Cash Incentive Compensation 4. Customer Experience for Service Cross-Channel Customer Service Knowledge Management Social Customer Service Eligibility Management Contracts, Assets, and Entitlements Industry-Specific Solutions eBilling Oracle's customer experience portfolio is socially infused at each layer of our pillars rather than simply bolted on as a side process. This combines with the power of the Cloud to run the parts of the solution that need the access, efficiency, and agility from a managed infrastructure. You can get the compliance control from on-premise backbone infrastructure systems that run your business and don't change that often. Please take advantage of our teams of Oracle customer experience professionals and our key agency and technology partner ecosystem. They can help you develop strategic solution roadmaps that build and deliver customer experience and that are tailored to your business needs and objectives. No one has built a better customer service portfolio to manage the entire customer journey than Oracle. It is backed by CX thought leadership programs, a commitment from our executives, and a worldview that your technology decisions must be driven by your customer experiences to succeed. If you’d like to follow up on this conversation, please leave a comment or contact me at [email protected]. You can get more information on Oracle’s complete customer experience solution here.

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  • 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.

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  • Archbeat Link-O-Rama Top 10 Facebook Faves for October 20-26, 2013

    - by OTN ArchBeat
    What are the 4,460 fans of the OTN ArchBeat Facebook Page talking about? The list below represents the Top 10 most popular articles, blog posts, and other content from across the community. Enterprise Grade Deployment Considerations for Oracle Identity Manager AD Connector | Firdaus Fraz Oracle Fusion Middleware solution architect Firdaus Fraz illustrates provides best practice recommendations for setting up an enterprise deployment environment for the OIM connector for Microsoft Active Directory. A Roadmap for SOA Development and Delivery | Mark Nelson Do you know the way to S-O-A? Mark Nelson does. His latest blog post, part of an ongoing series, will help to keep you from getting lost along the way. The road ahead for WebLogic 12c | Edwin Biemond Oracle ACE Edwin Biemond shares his thoughts on announced new features in Oracle WebLogic 12.1.3 & 12.1.4 and compares those upcoming releases to Oracle WebLogic 12.1.2. Oracle GoldenGate 12c - New Release, New Features | Michael Rainey Rittman Mead's Michael Rainey takes you on guided tour through the GoldenGate 12c features that "are relevant to data warehouse and data migration work we typically see in the business intelligence world." Reproducing WebLogic Stuck Threads with ADF CreateInsert Operation and ORDER BY Clause | Andrejus Baranovsikis Another post from Oracle ACE Director Andrejus Baranovsikis on dealing with WebLogic Stuck Threads. This one includes a test case application you can download. The Impact of SaaS - The Times They Are A-Changin' | Floyd Teter Oracle ACE Director Floyd Teter shares some truly interesting insight gained in conversations with three Fortune 500 CIOs. Configure Oracle Identity Manager AD/LDAP Authentication | Arda Eralp A step-by-step how-to from a member of the Fusion Middleware Applications Consultancy team. Java-Powered Robot Named NAO Wows Crowds | Tori Wieldt Tori Wieldt interviews a robot and human. Updated ODI Statement of Direction | Robert Schweighardt Heads up Oracle Data Integrator fans! A new product statement of direction document is available, offering "an overview of the strategic product plans for Oracle’s data integration products for bulk data movement and transformation, specifically Oracle Data Integrator (ODI) and Oracle Warehouse Builder (OWB)." Oracle BI Apps 11.1.1.7.1 – GoldenGate Integration - Part 2: Setup and Configuration | Michael Rainey Michael Rainey continues his series with another technical article for you GoldenGate fans. Thought for the Day "Intuition will tell the thinking mind where to look next." — Jonas Salk, American medical researcher and virologist (October 28, 1914 – June 23, 1995) Source: brainyquote.com

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