Search Results

Search found 1955 results on 79 pages for 'lexical cast'.

Page 57/79 | < Previous Page | 53 54 55 56 57 58 59 60 61 62 63 64  | Next Page >

  • A Solution For (IEnumerable<Base>)Derive; Yet?

    - by acidzombie24
    I have D1 and D2 which derive from B. When i write var ls = (IEnumerable<B>)(cond?lsD1:lsD2); I get a runtime cast error. IIRC this is a well known problem. My question is 1) Is this allowed yet? perhaps in .NET 4? I have 2010 but my project is a few months old, large and targets 3.5. 2) Is there a simple workaround? I only need to read the list not add anything or remove. Actually, ToArray() would probably work but is there another solution?

    Read the article

  • Wherewith replace Dictionary.Where(p => p.Key is T)

    - by abatishchev
    I have a System.Collections.Generic.Dictionary<System.Web.UI.Control, object> where all keys can be either type of System.Web.UI.WebControls.HyperLink or type of System.Web.UI.WebControls.Label. I want to change Text property of each control. Because HyperLink doesn't implement (why??) ITextControl, I need to cast Label or HyperLink explicitly: Dictionary<Control,object> dic = .. dic .Where(p => p.Key is HyperLink) .ForEach(c => ((HyperLink)c).Text = "something") dic .Where(p => p.Key is Label) .ForEach(c => ((Label)c).Text = "something") Are there ways to workaround such approach?

    Read the article

  • error message fix

    - by user1722654
    for (int i = 0; i < dataGridView1.Rows.Count; i++) { //bool sleected = false; if (dataGridView1.Rows[i].Cells[3].Value != null) { selected.Add(i); } } //string donew = ""; // line off error textBox1.Text = ((String)dataGridView1.Rows[1].Cells[2].Value); /* for (int i = 0; i < selected.Count; i++) { textAdded.Add((String)dataGridView1.Rows[0].Cells[2].Value); // donew += (String)dataGridView1.Rows[selected[i]].Cells[2].Value; }*/ I keep getting the error Unable to cast object of type 'System.Double' to type 'System.String' What can I do to overcome this?

    Read the article

  • Implicit type conversion in DB/2 inserts?

    - by IronGoofy
    We're using SQL Inserts to insert some data via a script into DB/2 tables, e.g. CREATE TABLE TICKETS (TICKETID VARCHAR(10) NOT NULL); On my home installation, this statement works fine (note that I'm using an integer which is autoatically cast into a VarChar): INSERT INTO TICKETS (TICKETID) VALUES (1); while at my customer's site I get a type error. My question(s): Is this behavior version dependent? (I use a DB2 Express V9.7, while the customer has an Enterprise V9.5) Is there a config option to change the behavior? (I would like my home install to behave as close as possible as the production environment is going to be.)

    Read the article

  • Casting in mixed type calculations in C?

    - by yCalleecharan
    Hi, If I define these variables: double x0, xn, h; int n; and I have this mathematical expression: h = (xn - x0)/n; Is it necessary that I cast n into double prior doing the division for maximum accuracy like in h = (xn - x0)/ (double) n; I wrote a program to check the above but both expressions give the same answers. I understand that C will promote the integer to double type as variables xn and x0 are of type double but strangely enough in a book, the second expression with casting was emphasized. Thanks a lot...

    Read the article

  • C++ Inheritance Question

    - by shaz
    I have a base class MessageHandler and 2 derived classes, MessageHandler_CB and MessageHandler_DQ. The derived classes redefine the handleMessage(...) method. MH_DQ processes a message and puts the result in a deque while MH_CB processes the message and then executes a callback function. The base class has a static callback function that I pass along with a this pointer to a library which calls the static callback when a new message is available for processing. My problem comes when I am in the static callback with a void * pointing to either a MH_DQ or a MH_CB. If I cast it to the base class the empty MessageHandler::handleMessage(...) method is called, rather than the version in the appropriate derived class. What is the best way to address this situation from a design perspective and/or what language features might help me to implement a solution to my problem? Thanks in advance!

    Read the article

  • Getting the fractional part of a float without using modf()

    - by knight666
    Hi, I'm developing for a platform without a math library, so I need to build my own tools. My current way of getting the fraction is to convert the float to fixed point (multiply with (float)0xFFFF, cast to int), get only the lower part (mask with 0xFFFF) and convert it back to a float again. However, the imprecision is killing me. I'm using my Frac() and InvFrac() functions to draw an anti-aliased line. Using modf I get a perfectly smooth line. With my own method pixels start jumping around due to precision loss. This is my code: const float fp_amount = (float)(0xFFFF); const float fp_amount_inv = 1.f / fp_amount; inline float Frac(float a_X) { return ((int)(a_X * fp_amount) & 0xFFFF) * fp_amount_inv; } inline float Frac(float a_X) { return (0xFFFF - (int)(a_X * fp_amount) & 0xFFFF) * fp_amount_inv; } Thanks in advance!

    Read the article

  • Is it possible in Scala to force the caller to specify a type parameter for a polymorphic method ?

    - by Alex Kravets
    //API class Node class Person extends Node object Finder { def find[T <: Node](name: String): T = doFind(name).asInstanceOf[T] } //Call site (correct) val person = find[Person]("joe") //Call site (dies with a ClassCast inside b/c inferred type is Nothing) val person = find("joe") In the code above the client site "forgot" to specify the type parameter, as the API writer I want that to mean "just return Node". Is there any way to define a generic method (not a class) to achieve this (or equivalent). Note: using a manifest inside the implementation to do the cast if (manifest != scala.reflect.Manifest.Nothing) won't compile ... I have a nagging feeling that some Scala Wizard knows how to use Predef.<:< for this :-) Ideas ?

    Read the article

  • Upcasting in C#: Making a Fruit a Pear

    - by Adam Kane
    Why can't I upcast (?) a Fruit to a Pear? public static class PearGenerator { public static Pear CreatePear () { // Make a new generic fruit. Fruit genericFruit = new Fruit(); // Upcast it to a pear. (Throws exception: Can't cast a Fruit to a Pear.) Pear pear = (Pear)genericFruit; // Return freshly grown pear. return ( pear ); } } public class Fruit { // some code } public class Pear : Fruit { public void PutInPie () { // some code } } Thanks!

    Read the article

  • How to do hex8 encoding in c?

    - by Tech163
    I am trying to encode a string in hex8 using c. The script I have right now is: int hex8 (char str) { str = printf("%x", str); if(strlen(str) == 1) { return printf("%s", "0", str); } else { return str; } } In this function, I will need to add a 0 ahead of the string if the length is less than 1. I don't know why I'm getting: passing argument 1 of 'strlen' makes pointer from integer without a cast Does anyone know why?

    Read the article

  • C++, is it possible to obtain the dimension of an array?

    - by aaa
    hi. Suppose I have some pointer, which I want to reinterpret as static dimension array reference: double *p; double (&r)[4] = ?(p); // some construct? // clarify template< size_t N> void function(double (&a)[N]); ... double *p; function(p); // this will not work. // I would like to cast p as to make it appear as double[N] Is it possible to do so? how do I do it?

    Read the article

  • C++: Checking for non-numeric input and assigning to a double

    - by Brundle
    Here is the code I have at the moment: char ch; int sum = 0; double values[10]; int i = 0; cin >> ch; while (!isalpha(ch)) { values[i] = ch; sum += values[i]; i++; cin >> ch; } What is happening is that if I enter the value 1, that gets assigned to ch as a char. Now ch is assigning it's value to a double and doing an implicit cast. So it is assigning the ASCII value of '1' to values[i]. I want it to just assign 1 to values[i]. Is there a better way to do this? Or is there something that I'm missing?

    Read the article

  • Network license control for a Java application

    - by user1461615
    I have been tasked with providing some form of network license control for a Java application. The app would be stored on a network drive and run from a client machine. The basic idea is that it will be able to work out how many times it is being run concurrently and prevent the N+1th user from running the software where N is the number of concurrent licenses the customer has purchased. Is this possible somehow with a Java application? I implemented a "solution" which relied on multi-cast UDP communication between the running instances of the application but this didn't work because on most networks this kind of communication is blocked by security measures. Is there a better way? I don't even mind if it requires JNI/JNA. N.B. The solution does not have to be that sophisticated or highly secure.

    Read the article

  • C# Why does calling an interface member from a class generate an error?

    - by Jack
    So I have an interface: interface IFoo { int Bar(); int this[int i] {get; set;} } And a class that derives from it class Foo : IFoo { public int IFoo.Bar() { //Implementation { public int IFoo.this[int i] { //Implementation } } Now, I try to do this: var fooey = new Foo(); int i = Fooey.Bar(); or this: int i = Fooey[4]; I would expect these to work properly. However, the compiler generates an error as if such members don't exist. Why is that? I am aware I can cast Foo as IFoo, but I am also aware that casting is costly to performance, which is often the reason to use interfaces in the first place. EDIT 1: These are the errors generated 'Foo' does not contain a definition for 'Bar' and no extension method 'Bar' accepting a first argument of type 'Foo' could be found (are you missing a using directive or an assembly reference?) "Cannot apply indexing to an expression of type 'Foo'"

    Read the article

  • Does C# 4's covariance support nesting of generics?

    - by Scott Bilas
    I don't understand why 'x' below converts, but 'y' and 'z' do not. var list = new List<List<int>>(); IEnumerable<List<int>> x = list; List<IEnumerable<int>> y = list; IEnumerable<IEnumerable<int>> z = list; Does the new covariance feature simply not work on generics of generics or am I doing something wrong? (I'd like to avoid using .Cast< to make y and z work.)

    Read the article

  • Linking each text word or words divided by comma into an existing URL?

    - by Mezelderz
    I am trying to auto add each word or words divided by comma into an existing url. I have url lets say http://stackoverflow.com/search?q=HERE IS THAT TEXT. I have this function: function movie_cast( $atts, $content = null ) { return '<div class="movie_cast">Cast: '.$content.'</div>'; } add_shortcode( 'movie_cast', 'movie_cast' ); I am using it: [movie_cast]Actor 1, Actor 2[/movie_cast] Output from this is just text: Actor 1, Actor 2 How can I get otput it like this: <a href="http://stackoverflow.com/search?q=Actor 1">Actor 1</a>, <a href="http://stackoverflow.com/search?q=Actor 2">Actor 2</a>

    Read the article

  • Why does gcc warn about incompatible struct assignment with a `self = [super initDesignatedInit];' c

    - by gavinbeatty
    I have the following base/derived class setup in Objective-C: @interface ASCIICodeBase : NSObject { @protected char code_[4]; } - (Base *)initWithASCIICode:(const char *)code; @end @implementation ASCIICodeBase - (ASCIICodeBase *)initWithCode:(const char *)code len:(size_t)len { if (len == 0 || len > 3) { return nil; } if (self = [super init]) { memset(code_, 0, 4); strncpy(code_, code, 3); } return self; } @end @interface CountryCode : ASCIICodeBase - (CountryCode *)initWithCode:(const char *)code; @end @implementation CountryCode - (CountryCode *)initWithCode:(const char *)code { size_t len = strlen(code); if (len != 2) { return nil; } self = [super initWithCode:code len:len]; // here return self; } @end On the line marked "here", I get the following gcc warning: warning: incompatible Objective-C types assigning 'struct ASCIICodeBase *', expected 'struct CurrencyCode *' Is there something wrong with this code or should I have the ASCIICodeBase return id? Or maybe use a cast on the "here" line?

    Read the article

  • referencing struct fields in c with square brackets and an index instead of . and ->?

    - by lsiebert
    Assuming I have a structure such as: typedef struct { char * string1; char * string2; } TWO_WORDS; such that all the fields are of the same type, and my main has TWO_WORDS tw; can I reference string1 with tw[0] and string2 with two[1]? If so: is this part of the c standard? do i have to cast the struct to an array first? what about fields which are different sizes in memory what about fields which are different types but the same size? can you do pointer arithmetic within a structure? -

    Read the article

  • private virtual function in derived class

    - by user1706047
    class base { public: virtual void doSomething() = 0; }; class derived : public base { **private:** virtual void doSomething(){cout<<"Derived fn"<<endl;} }; now if i do the following: base *b=new child; b->doSomething(); //it calls the derived class fn even if that is private. Question: 1.its able to call the derived class fn even if that is private.How is it possible? Now if i change the inheritance access specifier from public to protected/private then i get compilation error as "'type cast' : conversion from 'Derived *' to 'base *' exists, but is inaccessible" Notes: I am aware on the concepts of the inheritance access specifiers.So in second case as its derived private/protected, its inaccessible. But here it confuses me for the first question. Any input will be highly appreciated

    Read the article

  • Are you cashing in on the MVP complimentary subscriptions ?

    - by Tarun Arora
    The two most asked questions in the Microsoft technology communities around the Microsoft MVP program are, 1. How do I become a Microsoft MVP? 2. What benefits do I get as an MVP? The answer to the first question has been well answered here. In this blog post, I’ll try and answer the second question.           Please find a comprehensive list of Not for Resale personal subscriptions of various products that Microsoft MVP’s are eligible for Product Description Details JetBrains Resharper, dotTrace, dotCover & WebStorm  https://www.jetbrains.com/resharper/buy/mvp.html RedGate Sql server development, database administration, .net development, azure development (merged with Cerebrata), mySQL development, Oracle development http://www.red-gate.com/community/mvp-program Pluralsight Pluralsight on demand training http://blog.pluralsight.com/2011/02/28/pluralsight-for-mvp/ Cerebrata Cloud storage studio and Azure Diagnostic Manager (part of redgate now) https://www.cerebrata.com/Offers/mvp.aspx Telerik Telerik Ultimate collection & Telerik TeamPulse http://blogs.telerik.com/blogs/posts/11-03-01/telerik-gift-for-microsoft-mvps.aspx Developer Express DevEx controls http://www.devexpress.com/Home/Community/mvp.xml InnerWorking 600 hours of .net training catalogue http://www.innerworkings.com/mvp Typemock Typemock Isolator, Typemock Isolator for Sharepoint developers, Typemock Isolator for web developers, TestDriven.NET http://www.typemock.com/mvp SpeakFlow A suite of tools for creating, managing, and delivering non-linear presentations http://www.speakflow.com/ TechSmith Camtasia Studio, SnagIt, screen cast http://www.techsmith.com/camtasia.html Altova Altova XML spy http://www.altova.com/xml-editor/ Visual SVN VisualSVN Subversion integration plug-in for Visual Studio http://www.visualsvn.com/visualsvn/purchase/mvp/ PreEmptive Solution Professional PreEmptive Analytics, Dotfuscator http://www.preemptive.com/landing/mvp Armadillo Armadillo Adaptive Bug Prevention http://www.armadilloverdrive.com/ IS Decisions NFR license to Userlock, RemoteExec, FileAudit & WinReporter http://www.isdecisions.com/download/mvp-mct-program.htm Idera SQL tools http://www.idera.com/Content/Home.aspx West Wind Help Builder Help builder solution http://www.west-wind.com/weblog/posts/2005/Mar/09/Are-you-a-Microsoft-MVP-Get-a-FREE-copy-of-West-Wind-Html-Help-Builder Bamboo Sharepoint tools http://community.bamboosolutions.com/blogs/partner-advantage-program/archive/2008/08/01/partner-advantage-program-mvp.aspx Nitriq Nitriq code analysis http://blog.nitriq.com/FreeLicensesForMicrosoftMVPs.aspx ByteScout Components, Libraries and Developer Tools http://bytescout.com/buy/purchase_nfr_for_mvp.html YourKit Java and .net Profiler http://yourkit.com/.net/profiler/index.jsp Aspose .NET components http://www.aspose.com/corporate/community/2012_05_08_nfr-licenses-for-community-leaders.aspx Apart from google bing fu; stackoverflow and breathtech were a great help in compiling the above list. If you know of any other benefits, offers or complimentary subscriptions on offer for MVPs not cover in the list above, please add to the comment thread and I’ll have it updated in the list. Enjoy

    Read the article

  • SQL SERVER – Fix Error: Microsoft OLE DB Provider for SQL Server error ’80040e07' or Microsoft SQL Native Client error ’80040e07'

    - by pinaldave
    I quite often receive questions where users are looking for solution to following error: Microsoft OLE DB Provider for SQL Server error ’80040e07′ Syntax error converting datetime from character string. OR Microsoft SQL Native Client error ’80040e07′ Syntax error converting datetime from character string. If you have ever faced above error – I have a very simple solution for you. The solution is being very check date which is inserted in the datetime column. This error often comes up when application or user is attempting to enter an incorrect date into the datetime field. Here is one of the examples – one of the reader was using classing ASP Application with OLE DB provider for SQL Server. When he tried to insert following script he faced above mentioned error. INSERT INTO TestTable (ID, MyDate) VALUES (1, '01-Septeber-2013') The reason for the error was simple as he had misspelled September word. Upon correction of the word, he was able to successfully insert the value and error was not there. Incorrect values or the typo’s are not the only reason for this error. There can be issues with cast or convert as well. If you try to attempt following code using SQL Native Client or in your application you will also get similar errors. SELECT CONVERT (datetime, '01-Septeber-2013', 112) The reason here is very simple, any conversion attempt or any other kind of operation on incorrect date/time string can lead to the above error. If you not using embeded dynamic code in your application language but using attempting similar operation on incorrect datetime string you will get following error. Msg 241, Level 16, State 1, Line 2 Conversion failed when converting date and/or time from character string. Remember: Check your values of the string when you are attempting to convert them to string – either there can be incorrect values or they may be incorrectly formatted. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL DateTime, SQL Error Messages, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

    Read the article

  • Easy Listening = CRM On Demand Podcasts

    - by Anne
    OK, here's my NEW favorite resource for CRM On Demand info -- podcasts! Specifically, the CRM On Demand Podcast site -- signed, sealed, and delivered with humor and know-how. Yes, I admit, I know the cast of characters. But let's face it, sometimes dealing with software is just soooo dry! Not so when discussed by the two main commentators, Louis Peters and Robert Davidson, whom someone once referred to as CRM On Demand's "Click and Clack." (Thought that was too good not to pass along!) Anyhow, another huge plus about the site is the option to listen OR to read. Out walking my dog or doing the dishes? Just turn up the podcast. Listening to music or watching TV? I'll read Louis's entertaining write-ups to glean great info about CRM On Demand in a very short period of time. So that you get a better understanding of why I like this site so much, here's a sampling of what's discussed: Five Things about Books of Business As Louis Peters put it in his entry, when you see "Five Things" in the title, "you'll know you're going to get some concrete advice that you can put to work right away." Well, Louis and Robert do just that, pointing you in the right direction when using Books of Business to segment data. Moving to Indexed Fields - A Rough Guide (only an article, not a podcast) I've read all about performance and even helped develop material around it. But nowhere have I heard indexed custom fields referred to as "super heroes." Louis and Robert use imaginative language to describe the process for moving your data to indexed fields for optimal performance. Data Access QA from the Forums I think that everyone would admit that data access and visibility is the most difficult topic to understand in CRM On Demand. Following up on their previous podcast on the same topic, Louis and Robert answer a few key questions from the many postings on the Oracle CRM On Demand forums. And I bet that the scenarios match many companies' business requirements...maybe even yours! We Need to Talk About Adoption Another expert, Tim Koehler, joins Louis to talk about how to drive user adoption: aligning product usage with business results, communicating why and how to use the product, getting feedback on usability, and so on. Hope I've made my point -- turn to these podcasts to hear knowledgeable folks discuss CRM On Demand tips and tricks in entertaining ways. One podcast is even called "SaaS Talk"!

    Read the article

  • Built-in card-reader doesn't work. HP Compaq nx6325 notebook

    - by user10940
    I have a HP-Compaq nx6325 notebook with an built-in card-reader (SD, MS/Pro, MMC, SM, XD) and the ubuntu (10.10.) don't see it. I've tried to install it manually, with this steps (and with this tifmxx driver), but doesn't work. The compile log: $ echo /home/tvera/downloads/cr_install /home/tvera/downloads/cr_install $ make -C /lib/modules/2.6.35-25-generic/build M=/home/tvera/downloads/cr_install make[1]: Entering directory `/usr/src/linux-headers-2.6.35-25-generic' CC [M] /home/tvera/downloads/cr_install/tifm_core.o In file included from /home/tvera/downloads/cr_install/tifm_core.c:12: /home/tvera/downloads/cr_install/linux/tifm.h:128: error: field ‘cdev’ has incomplete type /home/tvera/downloads/cr_install/tifm_core.c: In function ‘tifm_uevent’: /home/tvera/downloads/cr_install/tifm_core.c:69: warning: passing argument 1 of ‘add_uevent_var’ from incompatible pointer type include/linux/kobject.h:244: note: expected ‘struct kobj_uevent_env *’ but argument is of type ‘char **’ /home/tvera/downloads/cr_install/tifm_core.c:69: warning: passing argument 2 of ‘add_uevent_var’ makes pointer from integer without a cast include/linux/kobject.h:244: note: expected ‘const char *’ but argument is of type ‘int’ /home/tvera/downloads/cr_install/tifm_core.c: At top level: /home/tvera/downloads/cr_install/tifm_core.c:161: warning: initialization from incompatible pointer type /home/tvera/downloads/cr_install/tifm_core.c: In function ‘tifm_free’: /home/tvera/downloads/cr_install/tifm_core.c:170: warning: type defaults to ‘int’ in declaration of ‘__mptr’ /home/tvera/downloads/cr_install/tifm_core.c:170: warning: initialization from incompatible pointer type /home/tvera/downloads/cr_install/tifm_core.c: At top level: /home/tvera/downloads/cr_install/tifm_core.c:177: error: unknown field ‘release’ specified in initializer /home/tvera/downloads/cr_install/tifm_core.c:178: warning: initialization from incompatible pointer type /home/tvera/downloads/cr_install/tifm_core.c: In function ‘tifm_alloc_adapter’: /home/tvera/downloads/cr_install/tifm_core.c:190: error: implicit declaration of function ‘class_device_initialize’ /home/tvera/downloads/cr_install/tifm_core.c: In function ‘tifm_add_adapter’: /home/tvera/downloads/cr_install/tifm_core.c:211: error: ‘BUS_ID_SIZE’ undeclared (first use in this function) /home/tvera/downloads/cr_install/tifm_core.c:211: error: (Each undeclared identifier is reported only once /home/tvera/downloads/cr_install/tifm_core.c:211: error: for each function it appears in.) /home/tvera/downloads/cr_install/tifm_core.c:212: error: implicit declaration of function ‘class_device_add’ /home/tvera/downloads/cr_install/tifm_core.c: In function ‘tifm_remove_adapter’: /home/tvera/downloads/cr_install/tifm_core.c:237: error: implicit declaration of function ‘class_device_del’ /home/tvera/downloads/cr_install/tifm_core.c: In function ‘tifm_free_adapter’: /home/tvera/downloads/cr_install/tifm_core.c:243: error: implicit declaration of function ‘class_device_put’ /home/tvera/downloads/cr_install/tifm_core.c: In function ‘tifm_alloc_device’: /home/tvera/downloads/cr_install/tifm_core.c:275: error: ‘struct device’ has no member named ‘bus_id’ /home/tvera/downloads/cr_install/tifm_core.c:275: error: ‘BUS_ID_SIZE’ undeclared (first use in this function) make[2]: *** [/home/tvera/downloads/cr_install/tifm_core.o] Error 1 make[1]: *** [_module_/home/tvera/downloads/cr_install] Error 2 make[1]: Leaving directory `/usr/src/linux-headers-2.6.35-25-generic' make: *** [all] Error 2 The output of lsusb: Bus 001 Device 005: ID 05e3:0702 Genesys Logic, Inc. USB 2.0 IDE Adapter Bus 003 Device 003: ID 0458:003a KYE Systems Corp. (Mouse Systems) NetScroll+ Mini Traveler Bus 003 Device 002: ID 08ff:2580 AuthenTec, Inc. AES2501 Fingerprint Sensor Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

    Read the article

  • Sharing data between graphics and physics engine in the game?

    - by PolGraphic
    I'm writing the game engine that consists of few modules. Two of them are the graphics engine and the physics engine. I wonder if it's a good solution to share data between them? Two ways (sharing or not) looks like that: Without sharing data GraphicsModel{ //some common for graphics and physics data like position //some only graphic data //like textures and detailed model's verticles that physics doesn't need }; PhysicsModel{ //some common for graphics and physics data like position //some only physics data //usually my physics data contains A LOT more informations than graphics data } engine3D->createModel3D(...); physicsEngine->createModel3D(...); //connect graphics and physics data //e.g. update graphics model's position when physics model's position will change I see two main problems: A lot of redundant data (like two positions for both physics and graphics data) Problem with updating data (I have to manually update graphics data when physics data changes) With sharing data Model{ //some common for graphics and physics data like position }; GraphicModel : public Model{ //some only graphics data //like textures and detailed model's verticles that physics doesn't need }; PhysicsModel : public Model{ //some only physics data //usually my physics data contains A LOT more informations than graphics data } model = engine3D->createModel3D(...); physicsEngine->assingModel3D(&model); //will cast to //PhysicsModel for it's purposes?? //when physics changes anything (like position) in model //(which it treats like PhysicsModel), the position for graphics data //will change as well (because it's the same model) Problems here: physicsEngine cannot create new objects, just "assing" existing ones from engine3D (somehow it looks more anti-independent for me) Casting data in assingModel3D function physicsEngine and graphicsEngine must be careful - they cannot delete data when they don't need them (because second one may need it). But it's rare situation. Moreover, they can just delete the pointer, not the object. Or we can assume that graphicsEngine will delete objects, physicsEngine just pointers to them. Which way is better? Which will produce more problems in the future? I like the second solution more, but I wonder why most graphics and physics engines prefer the first one (maybe because they normally make only graphics or only physics engine and somebody else connect them in the game?). Have they any more hidden pros & contras?

    Read the article

  • Subterranean IL: Filter exception handlers

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

    Read the article

< Previous Page | 53 54 55 56 57 58 59 60 61 62 63 64  | Next Page >