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  • Modular GWT design concerns

    - by GlGuru
    Hi, I have a couple of questions regarding a modular GWT based application framework. I have some ideas about them but being new to the field of web development I feel they are far from ideal. I'd appreciate a few comments and suggestions in this regard. Here are my questions: I am developing a framework which will allow third parties to embed GWT applications into our website and do some communication with them using simple iFrame postMessage. All these third party modules are going to use our SDK which is also GWT based. The problem arises that even though all the modules will be using the same codebase there is going to be a massive overheard in the amount of duplicate Javascript code (i.e. our common SDK code base which is quite large) being downloaded on the client's machine. This is highly redundant and problematic, not only due to the sheer size of duplicate code but, also due to the fact that subsequent updates of the SDK would require the modules to be recompiled which is going to create a DLL hell kind of scenario in the long run. What is the best way of doing this kind of thing? Is there a way where I can have some static GWT code (i.e. the SDK) and the dynamic GWT module refers to it (even if lies on a different domain) and it all work happily? The other part of the problem lies in providing robust scripting front end to the SDK. At first it appears to be trivial since Javascript itself is a scripting language. However, I do not know how to load and call a piece of pure Javascript code at runtime? I am willing to put restrictions on the target Javascript (i.e. having a function main and unique namespace or something). Furthermore the Javascript will come as a string from a database and not as a full URL. If its doable in Javascript how does one get this right in GWT i.e. forcing the compiler to emit a certain function in the generated Javascript? This I believe can be lesser of a problem by having a stub Javascript with all the right requirements which just loads up a GWT generated Javascript. Is any of this possible at all? I generally hate to be this verbose but I hope to find a quick solution to the problem as its holding up my progress. I'd highly appreciate any comments, suggestions and experiences.

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  • Reading and writing C++ vector to a file

    - by JB
    For some graphics work I need to read in a large amount of data as quickly as possible and would ideally like to directly read and write the data structures to disk. Basically I have a load of 3d models in various file formats which take too long to load so I want to write them out in their "prepared" format as a cache that will load much faster on subsequent runs of the program. Is it safe to do it like this? My worries are around directly reading into the data of the vector? I've removed error checking, hard coded 4 as the size of the int and so on so that i can give a short working example, I know it's bad code, my question really is if it is safe in c++ to read a whole array of structures directly into a vector like this? I believe it to be so, but c++ has so many traps and undefined behavour when you start going low level and dealing directly with raw memory like this. I realise that number formats and sizes may change across platforms and compilers but this will only even be read and written by the same compiler program to cache data that may be needed on a later run of the same program. #include <fstream> #include <vector> using namespace std; struct Vertex { float x, y, z; }; typedef vector<Vertex> VertexList; int main() { // Create a list for testing VertexList list; Vertex v1 = {1.0f, 2.0f, 3.0f}; list.push_back(v1); Vertex v2 = {2.0f, 100.0f, 3.0f}; list.push_back(v2); Vertex v3 = {3.0f, 200.0f, 3.0f}; list.push_back(v3); Vertex v4 = {4.0f, 300.0f, 3.0f}; list.push_back(v4); // Write out a list to a disk file ofstream os ("data.dat", ios::binary); int size1 = list.size(); os.write((const char*)&size1, 4); os.write((const char*)&list[0], size1 * sizeof(Vertex)); os.close(); // Read it back in VertexList list2; ifstream is("data.dat", ios::binary); int size2; is.read((char*)&size2, 4); list2.resize(size2); // Is it safe to read a whole array of structures directly into the vector? is.read((char*)&list2[0], size2 * sizeof(Vertex)); }

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  • Some clarification on rvalue references

    - by Dennis Zickefoose
    First: where are std::move and std::forward defined? I know what they do, but I can't find proof that any standard header is required to include them. In gcc44 sometimes std::move is available, and sometimes its not, so a definitive include directive would be useful. When implementing move semantics, the source is presumably left in an undefined state. Should this state necessarily be a valid state for the object? Obviously, you need to be able to call the object's destructor, and be able to assign to it by whatever means the class exposes. But should other operations be valid? I suppose what I'm asking is, if your class guarantees certain invariants, should you strive to enforce those invariants when the user has said they don't care about them anymore? Next: when you don't care about move semantics, are there any limitations that would cause a non-const reference to be preferred over an rvalue reference when dealing with function parameters? void function(T&); over void function(T&&); From a caller's perspective, being able to pass functions temporary values is occasionally useful, so it seems as though one should grant that option whenever it is feasible to do so. And rvalue references are themselves lvalues, so you can't inadvertently call a move-constructor instead of a copy-constructor, or something like that. I don't see a downside, but I'm sure there is one. Which brings me to my final question. You still can not bind temporaries to non-const references. But you can bind them to non-const rvalue references. And you can then pass along that reference as a non-const reference in another function. void function1(int& r) { r++; } void function2(int&& r) { function1(r); } int main() { function1(5); //bad function2(5); //good } Besides the fact that it doesn't do anything, is there anything wrong with that code? My gut says of course not, since changing rvalue references is kind of the whole point to their existence. And if the passed value is legitimately const, the compiler will catch it and yell at you. But by all appearances, this is a runaround of a mechanism that was presumably put in place for a reason, so I'd just like confirmation that I'm not doing anything foolish.

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  • Android passing an arraylist back to parent activity

    - by Nicklas O
    Hi there. I've been searching for a simple example of this with no luck. In my android application I have two activities: 1. The main activity which is launched at startup 2. A second activity which is launched by pressing a button on the main activty. When the second activity is finished (by pressing a button) I want it to send back an ArrayList of type MyObject to the main activity and close itself, which the main activity can then do whatever with it. How would I go about achieving this? I have been trying a few things but it is crashing my application when I start the second activity. When the user presses button to launch second activity: Intent i = new Intent(MainActivity.this, secondactivity.class); startActivityForResult(i, 1); The array which is bundled back after pressing a button on the second activity: Intent intent= getIntent(); Bundle b = new Bundle(); b.putParcelableArrayList("myarraylist", mylist); intent.putExtras(b); setResult(RESULT_OK, intent); finish(); And finally a listener on the main activity (although I'm not sure of 100% when this code launches...) protected void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); if(resultCode==RESULT_OK && requestCode==1){ Bundle extras = data.getExtras(); final ArrayList<MyObject> mylist = extras.getParcelableArrayList("myarraylist"); Toast.makeText(MainActivity.this, mylist.get(0).getName(), Toast.LENGTH_SHORT).show(); } } Any ideas where I am going wrong? The onActivityResult() seems to be crashing my application. EDIT: This is my class MyObject, its called plan and has a name and an id import android.os.Parcel; import android.os.Parcelable; public class Plan implements Parcelable{ private String name; private String id; public Plan(){ } public Plan(String name, String id){ this.name = name; this.id = id; } public String getName(){ return name; } public void setName(String name){ this.name = name; } public String getId(){ return id; } public void setId(String id){ this.id = id; } public String toString(){ return "Plan ID: " + id + " Plan Name: " + name; } @Override public int describeContents() { // TODO Auto-generated method stub return 0; } @Override public void writeToParcel(Parcel dest, int flags) { dest.writeString(id); dest.writeString(name); } public static final Parcelable.Creator<Plan> CREATOR = new Parcelable.Creator<Plan>() { public Plan createFromParcel(Parcel in) { return new Plan(); } @Override public Plan[] newArray(int size) { // TODO Auto-generated method stub return new Plan[size]; } }; } This is my logcat E/AndroidRuntime( 293): java.lang.RuntimeException: Unable to instantiate activ ity ComponentInfo{com.daniel.android.groupproject/com.me.android.projec t.secondactivity}: java.lang.NullPointerException E/AndroidRuntime( 293): at android.app.ActivityThread.performLaunchActiv ity(ActivityThread.java:2417) E/AndroidRuntime( 293): at android.app.ActivityThread.handleLaunchActivi ty(ActivityThread.java:2512) E/AndroidRuntime( 293): at android.app.ActivityThread.access$2200(Activi tyThread.java:119) E/AndroidRuntime( 293): at android.app.ActivityThread$H.handleMessage(Ac tivityThread.java:1863) E/AndroidRuntime( 293): at android.os.Handler.dispatchMessage(Handler.ja va:99) E/AndroidRuntime( 293): at android.os.Looper.loop(Looper.java:123) E/AndroidRuntime( 293): at android.app.ActivityThread.main(ActivityThrea d.java:4363) E/AndroidRuntime( 293): at java.lang.reflect.Method.invokeNative(Native Method) E/AndroidRuntime( 293): at java.lang.reflect.Method.invoke(Method.java:5 21) E/AndroidRuntime( 293): at com.android.internal.os.ZygoteInit$MethodAndA rgsCaller.run(ZygoteInit.java:860) E/AndroidRuntime( 293): at com.android.internal.os.ZygoteInit.main(Zygot eInit.java:618) E/AndroidRuntime( 293): at dalvik.system.NativeStart.main(Native Method) E/AndroidRuntime( 293): Caused by: java.lang.NullPointerException E/AndroidRuntime( 293): at com.daniel.android.groupproject.login.<init>( login.java:51) E/AndroidRuntime( 293): at java.lang.Class.newInstanceImpl(Native Method ) E/AndroidRuntime( 293): at java.lang.Class.newInstance(Class.java:1479) E/AndroidRuntime( 293): at android.app.Instrumentation.newActivity(Instr umentation.java:1021) E/AndroidRuntime( 293): at android.app.ActivityThread.performLaunchActiv ity(ActivityThread.java:2409) E/AndroidRuntime( 293): ... 11 more

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  • How to hide/show a Process using c#?

    - by aF
    Hello, While executing my program, I want to hide/minimize Microsoft Speech Recognition Application: and at the end I want to show/maximize using c#! This process is not started by me so I can't give control the process startInfo. I've tried to use user32.dll methods such as: ShowWindow AnimatedWindows AnimatedWindows With all of them I have the same problem. I can hide the windows (althought I have to call one of the methods two times with SW_HIDE option), but when I call the method with a SW_SHOW flag, it simply doesn't shows.. How can I maximize/show after hiding the process? Thanks in advance! Here is some pieces of the code, now implemented to use SetWindowPlacement: { [DllImport("user32.dll")] [return: MarshalAs(UnmanagedType.Bool)] public static extern bool GetWindowPlacement(IntPtr hWnd, ref WINDOWPLACEMENT lpwndpl); [DllImport("user32.dll", SetLastError = true)] [return: MarshalAs(UnmanagedType.Bool)] static extern bool SetWindowPlacement(IntPtr hWnd, [In] ref WINDOWPLACEMENT lpwndpl); [DllImport("user32.dll")] public static extern Boolean ShowWindowAsync(IntPtr hWnd, Int32 nCmdShow); [DllImport("user32.dll")] public static extern Boolean SetForegroundWindow(IntPtr hWnd); [DllImport("user32.dll")] public static extern Boolean ShowWindow(IntPtr hWnd, Int32 nCmdShow); [DllImport("user32.dll")] public static extern Boolean AnimateWindow(IntPtr hWnd, uint dwTime, uint dwFlags); [DllImport("dwmapi.dll")] public static extern int DwmSetWindowAttribute(IntPtr hwnd, uint dwAttribute, IntPtr pvAttribute, IntPtr lol); //Definitions For Different Window Placement Constants const UInt32 SW_HIDE = 0; const UInt32 SW_SHOWNORMAL = 1; const UInt32 SW_NORMAL = 1; const UInt32 SW_SHOWMINIMIZED = 2; const UInt32 SW_SHOWMAXIMIZED = 3; const UInt32 SW_MAXIMIZE = 3; const UInt32 SW_SHOWNOACTIVATE = 4; const UInt32 SW_SHOW = 5; const UInt32 SW_MINIMIZE = 6; const UInt32 SW_SHOWMINNOACTIVE = 7; const UInt32 SW_SHOWNA = 8; const UInt32 SW_RESTORE = 9; public sealed class AnimateWindowFlags { public const int AW_HOR_POSITIVE = 0x00000001; public const int AW_HOR_NEGATIVE = 0x00000002; public const int AW_VER_POSITIVE = 0x00000004; public const int AW_VER_NEGATIVE = 0x00000008; public const int AW_CENTER = 0x00000010; public const int AW_HIDE = 0x00010000; public const int AW_ACTIVATE = 0x00020000; public const int AW_SLIDE = 0x00040000; public const int AW_BLEND = 0x00080000; } public struct WINDOWPLACEMENT { public int length; public int flags; public int showCmd; public System.Drawing.Point ptMinPosition; public System.Drawing.Point ptMaxPosition; public System.Drawing.Rectangle rcNormalPosition; } //this works param = new WINDOWPLACEMENT(); param.length = Marshal.SizeOf(typeof(WINDOWPLACEMENT)); param.showCmd = (int)SW_HIDE; lol = SetWindowPlacement(theprocess.MainWindowHandle, ref param); // this doesn't work WINDOWPLACEMENT param = new WINDOWPLACEMENT(); param.length = Marshal.SizeOf(typeof(WINDOWPLACEMENT)); param.showCmd = SW_SHOW; lol = GetWindowPlacement(theprocess.MainWindowHandle, ref param);

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  • Few iPhone noob questions

    - by mshsayem
    Why should I declare local variables as 'static' inside a method? Like: static NSString *cellIdentifier = @"Cell"; Is it a performance advantage? (I know what 'static' does; in C context) What does this syntax mean?[someObj release], someObj = nil; Two statements? Why should I assign nil again? Is not 'release' enough? Should I do it for all objects I allocate/own? Or for just view objects? Why does everyone copy NSString, but retains other objects (in property declaration)? Yes, NSStrings can be changed, but other objects can be changed also, right? Then why 'copy' for just NSString, not for all? Is it just a defensive convention? Shouldn't I release constant NSString? Like here:NSString *CellIdentifier = @"Cell"; Why not? Does the compiler allocate/deallocate it for me? In some tutorial application I observed these (Built with IB): Properties(IBOutlet, with same ivar name): window, someLabel, someTextField, etc etc... In the dealloc method, although the window ivar was released, others were not. My question is: WHY? Shouldn't I release other ivars(labels, textField) as well? Why not? Say, I have 3 cascaded drop-down lists. I mean, based on what is selected on the first list, 2nd list is populated and based on what is selected on the second list, 3rd list is populated. What UI components can reflect this best? How is drop-down list presented in iPhone UI? Tableview with UIPicker? When should I update the 2nd, 3rd list? Or just three labels which have touch events? Can you give me some good example tutorials about Core-Data? (Not just simple data fetching and storing on 2/3 tables with 1/2 relationship) How can I know whether my app is leaking memory? Any tools?

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  • Internet Explorer Automation: how to suppress Open/Save dialog?

    - by Vladimir Dyuzhev
    When controlling IE instance via MSHTML, how to suppress Open/Save dialogs for non-HTML content? I need to get data from another system and import it into our one. Due to budget constraints no development (e.g. WS) can be done on the other side for some time, so my only option for now is to do web scrapping. The remote site is ASP.NET-based, so simple HTML requests won't work -- too much JS. I wrote a simple C# application that uses MSHTML and SHDocView to control an IE instance. So far so good: I can perform login, navigate to desired page, populate required fields and do submit. Then I face a couple of problems: First is that report is opening in another window. I suspect I can attach to that window too by enumerating IE windows in the system. Second, more troublesome, is that report itself is CSV file, and triggers Open/Save dialog. I'd like to avoid it and make IE save the file into given location OR I'm fine with programmatically clicking dialog buttons too (how?) I'm actually totally non-Windows guy (unix/J2EE), and hope someone with better knowledge would give me a hint how to do those tasks. Thanks! UPDATE I've found a promising document on MSDN: http://msdn.microsoft.com/en-ca/library/aa770041.aspx Control the kinds of content that are downloaded and what the WebBrowser Control does with them once they are downloaded. For example, you can prevent videos from playing, script from running, or new windows from opening when users click on links, or prevent Microsoft ActiveX controls from downloading or executing. Slowly reading through... UPDATE 2: MADE IT WORK, SORT OF... Finally I made it work, but in an ugly way. Essentially, I register a handler "before navigate", then, in the handler, if the URL is matching my target file, I cancel the navigation, but remember the URL, and use WebClient class to access and download that temporal URL directly. I cannot copy the whole code here, it contains a lot of garbage, but here are the essential parts: Installing handler: _IE2.FileDownload += new DWebBrowserEvents2_FileDownloadEventHandler(IE2_FileDownload); _IE.BeforeNavigate2 += new DWebBrowserEvents2_BeforeNavigate2EventHandler(IE_OnBeforeNavigate2); Recording URL and then cancelling download (thus preventing Save dialog to appear): public string downloadUrl; void IE_OnBeforeNavigate2(Object ob1, ref Object URL, ref Object Flags, ref Object Name, ref Object da, ref Object Head, ref bool Cancel) { Console.WriteLine("Before Navigate2 "+URL); if (URL.ToString().EndsWith(".csv")) { Console.WriteLine("CSV file"); downloadUrl = URL.ToString(); } Cancel = false; } void IE2_FileDownload(bool activeDocument, ref bool cancel) { Console.WriteLine("FileDownload, downloading "+downloadUrl+" instead"); cancel = true; } void IE_OnNewWindow2(ref Object o, ref bool cancel) { Console.WriteLine("OnNewWindow2"); _IE2 = new SHDocVw.InternetExplorer(); _IE2.BeforeNavigate2 += new DWebBrowserEvents2_BeforeNavigate2EventHandler(IE_OnBeforeNavigate2); _IE2.Visible = true; o = _IE2; _IE2.FileDownload += new DWebBrowserEvents2_FileDownloadEventHandler(IE2_FileDownload); _IE2.Silent = true; cancel = false; return; } And in the calling code using the found URL for direct download: ... driver.ClickButton(".*_btnRunReport"); driver.WaitForComplete(); Thread.Sleep(10000); WebClient Client = new WebClient(); Client.DownloadFile(driver.downloadUrl, "C:\\affinity.dump"); (driver is a simple wrapper over IE instance = _IE) Hope that helps someone.

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  • a script translatable to JavaScript with callback-hell automatic avoider :-)

    - by m1uan
    I looking for "translator" for JavaScript like already is CoffeScript, which will be work for example with forEach (inspired by Groovy) myArray.forEach() -> val, idx { // do something with value and idx } translate to JavaScript myArray.forEach(function(val, idx){ // do something with value and idx }); or something more usefull... function event(cb){ foo()-> err, data1; bar(data1)-> err, data2; cb(data2); } the method are encapsulated function event(cb){ foo(function(err,data1){ bar(data1, function(err, data2) { cb(data2); }); }); } I want ask if similar "compiler" to JavaScript like this even better already doesn't exists? What would be super cool... my code in nodejs looks mostly like this :-) function dealer(cb){ async.parallel([ function(pcb){ async.watterfall([function(wcb){ first(function(a){ wcb(a); }); }, function(a, wcb){ thirt(a, function(c){ wcb(c); }); fourth(a, function(d){ // dealing with “a” as well and nobody care my result }); }], function(err, array_with_ac){ pcb(array_with_ac); }); }, function(pcb){ second(function(b){ pcb(b);}); }], function(err, data){ cb(data[0][0]+data[1]+data[0][1]); // dealing with “a” “b” and “c” not with “d” }); } but, look how beautiful and readable the code could be: function dealer(cb){ first() -> a; second() -> b; third(a) -> c; // dealing with “a” fourth(a) -> d; // dealing with “a” as well and nobody care about my result cb(a+b+c); // dealing with “a” “b” and “c” not with “d” } yes this is ideal case when the translator auto-decide, method need to be run as parallel and method need be call after finish another method. I can imagine it's works Please, do you know about something similar? Thank you for any advice;-)

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  • Converting C source to C++

    - by Barry Kelly
    How would you go about converting a reasonably large (300K), fairly mature C codebase to C++? The kind of C I have in mind is split into files roughly corresponding to modules (i.e. less granular than a typical OO class-based decomposition), using internal linkage in lieu private functions and data, and external linkage for public functions and data. Global variables are used extensively for communication between the modules. There is a very extensive integration test suite available, but no unit (i.e. module) level tests. I have in mind a general strategy: Compile everything in C++'s C subset and get that working. Convert modules into huge classes, so that all the cross-references are scoped by a class name, but leaving all functions and data as static members, and get that working. Convert huge classes into instances with appropriate constructors and initialized cross-references; replace static member accesses with indirect accesses as appropriate; and get that working. Now, approach the project as an ill-factored OO application, and write unit tests where dependencies are tractable, and decompose into separate classes where they are not; the goal here would be to move from one working program to another at each transformation. Obviously, this would be quite a bit of work. Are there any case studies / war stories out there on this kind of translation? Alternative strategies? Other useful advice? Note 1: the program is a compiler, and probably millions of other programs rely on its behaviour not changing, so wholesale rewriting is pretty much not an option. Note 2: the source is nearly 20 years old, and has perhaps 30% code churn (lines modified + added / previous total lines) per year. It is heavily maintained and extended, in other words. Thus, one of the goals would be to increase mantainability. [For the sake of the question, assume that translation into C++ is mandatory, and that leaving it in C is not an option. The point of adding this condition is to weed out the "leave it in C" answers.]

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  • which way is correct to retrive data from oracle??

    - by rima
    before answer me plz thinking about the futures of these kind of program and answer me plz. I wanna get some data from oracle server like: 1-get all the function,package,procedure and etc for showing them or drop them & etc... 2-compile my *.sql files,get the result if they have problem & etc... becuz I was beginner in oracle first of all I for solve the second problem I try to connect to sqlPlus by RUN sqlplus and trace the output(I mean,I change the output stream of shell and trace what happend and handle the assigned message to customer. NOW THIS PART SUCCEED. just a little bit I have problem with get all result because the output is asynchronous.any way... [in this case I log in to oracle Server by send argument to the sqlplus by make a process in c#] after that I try to get all function,package or procedure name,but I have problem in speed!so I try to use oracle.DataAccess.dll to connect the database. now I m so confusing about: which way is correct way to build a program that work like Oracle Developer! I do not have any experience for like these program how work. If Your answer is I must use the second way follow this part plz: I search a little bit the Golden,PLedit (Benthic software),I have little bit problem how I must create the connection string?because I thinking about how I can find the host name or port number that oracle work on them?? am I need read the TNSNames.Ora file? IF your answer is I must use the first way follow this part plz: do u have any Idea for how I parse the output?because for example the result of a table is so confusing...[i can handle & program it but I really need someone experience,because the important things to me learn how such software work so nice and with quick response?] All of the has different style in output... If you are not sure Can u help me which book can help me in this way i become expert? becuz for example all the C# write just about how u can connect to DB and the DB books write how u can use this DB program,I looking for a book that give me some Idea how develop an interface for do transaction between these two.not simple send and receive data,for example how write a compiler for them. the language of book is not different for me i know C#,java,VB,sql,Oracle Thanks.

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  • Template function as a template argument

    - by Kos
    I've just got confused how to implement something in a generic way in C++. It's a bit convoluted, so let me explain step by step. Consider such code: void a(int) { // do something } void b(int) { // something else } void function1() { a(123); a(456); } void function2() { b(123); b(456); } void test() { function1(); function2(); } It's easily noticable that function1 and function2 do the same, with the only different part being the internal function. Therefore, I want to make function generic to avoid code redundancy. I can do it using function pointers or templates. Let me choose the latter for now. My thinking is that it's better since the compiler will surely be able to inline the functions - am I correct? Can compilers still inline the calls if they are made via function pointers? This is a side-question. OK, back to the original point... A solution with templates: void a(int) { // do something } void b(int) { // something else } template<void (*param)(int) > void function() { param(123); param(456); } void test() { function<a>(); function<b>(); } All OK. But I'm running into a problem: Can I still do that if a and b are generics themselves? template<typename T> void a(T t) { // do something } template<typename T> void b(T t) { // something else } template< ...param... > // ??? void function() { param<SomeType>(someobj); param<AnotherType>(someotherobj); } void test() { function<a>(); function<b>(); } I know that a template parameter can be one of: a type, a template type, a value of a type. None of those seems to cover my situation. My main question is hence: How do I solve that, i.e. define function() in the last example? (Yes, function pointers seem to be a workaround in this exact case - provided they can also be inlined - but I'm looking for a general solution for this class of problems).

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  • c++ class member functions instatiated by traits

    - by Jive Dadson
    I am reluctant to say I can't figure this out, but I can't figure this out. I've googled and searched stackoverflow, and come up empty. The abstract, and possibly overly vague form of the question is, how can I use the traits-pattern to instantiate non-virtual member functions? The question came up while modernizing a set of multivariate function optimizers that I wrote more than 10 years ago. The optimizers all operate by selecting a straight-line path through the parameter space away from the current best point (the "update"), then finding a better point on that line (the "line search"), then testing for the "done" condition, and if not done, iterating. There are different methods for doing the update, the line-search, and conceivably for the done test, and other things. Mix and match. Different update formulae require different state-variable data. For example, the LMQN update requires a vector, and the BFGS update requires a matrix. If evaluating gradients is cheap, the line-search should do so. If not, it should use function evaluations only. Some methods require more accurate line-searches than others. Those are just some examples. The original version instantiates several of the combinations by means of virtual functions. Some traits are selected by setting mode bits that are tested at runtime. Yuck. It would be trivial to define the traits with #define's and the member functions with #ifdef's and macros. But that's so twenty years ago. It bugs me that I cannot figure out a whiz-bang modern way. If there were only one trait that varied, I could use the curiously recurring template pattern. But I see no way to extend that to arbitrary combinations of traits. I tried doing it using boost::enable_if, etc.. The specialized state info was easy. I managed to get the functions done, but only by resorting to non-friend external functions that have the this-pointer as a parameter. I never even figured out how to make the functions friends, much less member functions. The compiler (vc++ 2008) always complained that things didn't match. I would yell, "SFINAE, you moron!" but the moron is probably me. Perhaps tag-dispatch is the key. I haven't gotten very deeply into that. Surely it's possible, right? If so, what is best practice?

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  • How do I do distributed UML development (à la FOSS)?

    - by James A. Rosen
    I have a UML project (built in IBM's Rational System Architect/Modeler, so stored in their XML format) that has grown quite large. Additionally, it now contains several pieces that other groups would like to re-use. I come from a software development (especially FOSS) background, and am trying to understand how to use that as an analogy here. The problem I am grappling with is similar to the Fragile Base Class problem. Let me start with how it works in an object-oriented (say, Java or Ruby) FOSS ecosystem: Group 1 publishes some "core" package, say "net/smtp version 1.0" Group 2 includes Group 1's net/smtp 1.0 package in the vendor library of their software project At some point, Group 1 creates a new 2.0 branch of net/smtp that breaks backwards compatibility (say, it removes an old class or method, or moves a class from one package to another). They tell users of the 1.0 version that it will be deprecated in one year. Group 2, when they have the time, updates to net/smtp 2.0. When they drop in the new package, their compiler (or test suite, for Ruby) tells them about the incompatibility. They do have to make some manual changes, but all of the changes are in the code, in plain text, a medium with which they are quite familiar. Plus, they can often use their IDE's (or text editor's) "global-search-and-replace" function once they figure out what the fixes are. When we try to apply this model to UML in RSA, we run into some problems. RSA supports some fairly powerful refactorings, but they seem to only work if you have write access to all of the pieces. If I rename a class in one package, RSA can rename the references, but only at the same time. It's very difficult to look at the underlying source (the XML) and figure out what's broken. To fix such a problem in the RSA editor itself means tons of clicking on things -- there is no good equivalent of "global-search-and-replace," at least not after an incomplete refactor. They real sticking point seems to be that RSA assumes that you want to do all your editing using their GUI, but that makes certain operations prohibitively difficult. Does anyone have examples of open-source UML projects that have overcome this problem? What strategies do they use for communicating changes?

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  • extensible database design: automatic ALTER TABLE or serialize() field BLOB ?

    - by mario
    I want an adaptable database scheme. But still use a simple table data gateway in my application, where I just pass an $data[] array for storing. The basic columns are settled in the initial table scheme. There will however arise a couple of meta fields later (ca 10-20). I want some flexibility there and not adapt the database manually each time, or -worse- change the application logic just because of new fields. So now there are two options which seem workable yet not overkill. But I'm not sure about the scalability or database drawbacks. (1) Automatic ALTER TABLE. Whenever the $data array is to be saved, the keys are compared against the current database columns. New columns get defined before the $data is INSERTed into the table. Actually seems simple enough in test code: function save($data, $table="forum") { // columns if ($new_fields = array_diff(array_keys($data), known_fields($table))) { extend_schema($table, $new_fields, $data); } // save $columns = implode("`, `", array_keys($data)); $qm = str_repeat(",?", count(array_keys($data)) - 1); echo ("INSERT INTO `$table` (`$columns`) VALUES (?$qm);"); function known_fields($table) { return unserialize(@file_get_contents("db:$table")) ?: array("id"); function extend_schema($table, $new_fields, $data) { foreach ($new_fields as $field) { echo("ALTER TABLE `$table` ADD COLUMN `$field` VARCHAR;"); Since it is mostly meta information fields, adding them just as VARCHAR seems sufficient. Nobody will query by them anyway. So the database is really just used as storage here. However, while I might want to add a lot of new $data fields on the go, they will not always be populated. (2) serialize() fields into BLOB. Any new/extraneous meta fields could be opaque to the database. Simply sorting out the virtual fields from the real database columns is simple. And the meta fields can just be serialize()d into a blob/text field then: function ext_save($data, $table="forum") { $db_fields = array("id", "content", "flags", "ext"); // disjoin foreach (array_diff(array_keys($data),$db_fields) as $key) { $data["ext"][$key] = $data[$key]; unset($data[$key]); } $data["ext"] = serialize($data["ext"]); Unserializing and unpacking this 'ext' column on read queries is a minor overhead. The advantage is that there won't be any sparsely filled columns in the database, so I guess it's compacter and faster than the AUTO ALTER TABLE approach. Of course, this method prevents ever using one of the new fields in a WHERE or GROUP BY clause. But I think none of the possible meta fields (user_agent, author_ip, author_img, votes, hits, last_modified, ..) would/should ever be used there anyway. So I currently prefer the 'ext' blob approach, even if it's a one-way ticket. How are such columns called usually? (looking for examples/doc) Would you use XML serialization for (very theoretical) in-database queries? The adapting table scheme seems a "cleaner" interface, even if most columns might remain empty then. How does that impact speed? How many such sparse VARCHAR fields can MySQL/innodb stomach? But most importantly: Is there any standard implementation for this? A pseudo ORM with automatic ALTER TABLE tricks? Storing a simple column list seems workable, but something like pdo::getColumnMeta would be more robust.

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  • Hierarchy inheritance

    - by reito
    I had faced the problem. In my C++ hierarchy tree I have two branches for entities of difference nature, but same behavior - same interface. I created such hierarchy trees (first in image below). And now I want to work with Item or Base classes independetly of their nature (first or second). Then I create one abstract branch for this use. My mind build (second in image below). But it not working. Working scheme seems (third in image below). It's bad logic, I think... Do anybody have some ideas about such hierarchy inheritance? How make it more logical? More simple for understanding? Image Sorry for my english - russian internet didn't help:) Update: You ask me to be more explicit, and I will be. In my project (plugins for Adobe Framemaker) I need to work with dialogs and GUI controls. In some places I working with WinAPI controls, and some other places with FDK (internal Framemaker) controls, but I want to work throw same interface. I can't use one base class and inherite others from it, because all needed controls - is a hierarchy tree (not one class). So I have one hierarchy tree for WinAPI controls, one for FDK and one abstract tree to use anyone control. For example, there is an Edit control (WinEdit and FdkEdit realization), a Button control (WinButton and FdkButton realization) and base entity - Control (WinControl and FdkControl realization). For now I can link my classes in realization trees (Win and Fdk) with inheritence between each of them (WinControl is base class for WinButton and WinEdit; FdkControl is base class for FdkButton and FdkEdit). And I can link to abstract classes (Control is base class for WinControl and FdkControl; Edit is base class for WinEdit and FdkEdit; Button is base class for WinButton and FdkButton). But I can't link my abstract tree - compiler swears. In fact I have two hierarchy trees, that I want to inherite from another one. Update: I have done this quest! :) I used the virtual inheritence and get such scheme (http://img12.imageshack.us/img12/7782/99614779.png). Abstract tree has only absolute abstract methods. All inheritence in abstract tree are virtual. Link from realization tree to abstract are virtual. On image shown only one realization tree for simplicity. Thanks for help!

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  • What is the best practice to segment c#.net projects based on a single base project

    - by Anthony
    Honestly, I can't word my question any better without describing it. I have a base project (with all its glory, dlls, resources etc) which is a CMS. I need to use this project as a base for othe custom bake projects. This base project is to be maintained and updated among all custom bake projects. I use subversion (Collabnet and Tortise SVN) I have two questions: 1 - Can I use subversion to share the base project among other projects What I mean here is can I "Checkout" the base project into another "Checked Out" project and have both update and commit seperatley. So, to paint a picture, let's say I am working on a custom project and I modify the core/base prject in some way (which I know will suit the others) can I then commit those changes and upon doing so when I update the base project in the other "Checked out" resources will it pull the changes? In short, I would like not to have to manually deploy updated core files whenever I make changes into each seperate project. 2 - If I create a custom file (let's say an webcontrol or aspx page etc) can I have it compile seperatley from the base project Another tricky one to explain. When I publish my web application it creates DLLs based on the namespaces of projects attached to it. So I may have a number of DLLs including the "Website's" namespace DLL, which could simply be website. I want to be able to make a seperate, custom, control which does not compile into those DLLs as the custom files should not rely on those DLLS to run. Is it as simple to set a seperate namespace for those files like CustomFiles.ProjectName for example? Think of the whole idea as adding modules to the .NET project, I don't want the module's code in any of the core DLLs but I do need for module to be able to access the core dlls. (There is no need for the core project to access the module code as it should be one way only in theory, though I reckon it woould not be possible anyway without using JSON/SOAP or something like that, maybe I am wrong.) I want to create a pluggable environment much like that of Joomla/Wordpress as since PHP generally doesn't have to be compiled first I see this is the reason why all this is possible/easy. The idea is to allow pluggable themes, modules etc etc. (I haven't tried simply adding .NET themes after compile/publish but I am assuming this is possible anyway? OR does the compiler need to reference items in the files?)

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  • Setting default values for inherited property without using accessor in Objective-C?

    - by Ben Stock
    I always see people debating whether or not to use a property's setter in the -init method. I don't know enough about the Objective-C language yet to have an opinion one way or the other. With that said, lately I've been sticking to ivars exclusively. It seems cleaner in a way. I don't know. I digress. Anyway, here's my problem … Say we have a class called Dude with an interface that looks like this: @interface Dude : NSObject { @private NSUInteger _numberOfGirlfriends; } @property (nonatomic, assign) NSUInteger numberOfGirlfriends; @end And an implementation that looks like this: @implementation Dude - (instancetype)init { self = [super init]; if (self) { _numberOfGirlfriends = 0; } } @end Now let's say I want to extend Dude. My subclass will be called Playa. And since a playa should have mad girlfriends, when Playa gets initialized, I don't want him to start with 0; I want him to have 10. Here's Playa.m: @implementation Playa - (instancetype)init { self = [super init]; if (self) { // Attempting to set the ivar directly will result in the compiler saying, // "Instance variable `_numberOfGirlfriends` is private." // _numberOfGirlfriends = 10; <- Can't do this. // Thus, the only way to set it is with the mutator: self.numberOfGirlfriends = 10; // Or: [self setNumberOfGirlfriends:10]; } } @end So what's a Objective-C newcomer to do? Well, I mean, there's only one thing I can do, and that's set the property. Unless there's something I'm missing. Any ideas, suggestions, tips, or tricks? Sidenote: The other thing that bugs me about setting the ivar directly — and what a lot of ivar-proponents say is a "plus" — is that there are no KVC notifications. A lot of times, I want the KVC magic to happen. 50% of my setters end in [self setNeedsDisplay:YES], so without the notification, my UI doesn't update unless I remember to manually add -setNeedsDisplay. That's a bad example, but the point stands. I utilize KVC all over the place, so without notifications, things can act wonky. Anyway, any info is much appreciated. Thanks!

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  • Moving from Windows to Ubuntu.

    - by djzmo
    Hello there, I used to program in Windows with Microsoft Visual C++ and I need to make some of my portable programs (written in portable C++) to be cross-platform, or at least I can release a working version of my program for both Linux and Windows. I am total newcomer in Linux application development (and rarely use the OS itself). So, today, I installed Ubuntu 10.04 LTS (through Wubi) and equipped Code::Blocks with the g++ compiler as my main weapon. Then I compiled my very first Hello World linux program, and I confused about the output program. I can run my program through the "Build and Run" menu option in Code::Blocks, but when I tried to launch the compiled application externally through a File Browser (in /media/MyNTFSPartition/MyProject/bin/Release; yes, I saved it in my NTFS partition), the program didn't show up. Why? I ran out of idea. I need to change my Windows and Microsoft Visual Studio mindset to Linux and Code::Blocks mindset. So I came up with these questions: How can I execute my compiled linux programs externally (outside IDE)? In Windows, I simply run the generated executable (.exe) file How can I distribute my linux application? In Windows, I simply distribute the executable files with the corresponding DLL files (if any) What is the equivalent of LIBs (static library) and DLLs (dynamic library) in linux and how to use them? In Windows/Visual Studio, I simply add the required libraries to the Additional Dependencies in the Project Settings, and my program will automatically link with the required static library(-ies)/DLLs. Is it possible to use the "binary form" of a C++ library (if provided) so that I wouldn't need to recompile the entire library source code? In Windows, yes. Sometimes precompiled *.lib files are provided. If I want to create a wxWidgets application in Linux, which package should I pick for Ubuntu? wxGTK or wxX11? Can I run wxGTK program under X11? In Windows, I use wxMSW, Of course. If question no. 4 is answered possible, are precompiled wxX11/wxGTK library exists out there? Haven't tried deep google search. In Windows, there is a project called "wxPack" (http://wxpack.sourceforge.net/) that saves a lot of my time. Sorry for asking many questions, but I am really confused on these linux development fundamentals. Any kind of help would be appreciated =) Thanks.

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  • BFS Shortest Path: Edge weight either 1 or 2

    - by Hackster
    I am trying to implement a shortest path algorithm using BFS. That is I am trying to find the shortest path from a specified vertex to every other vertex. However, its a special case where all edge weights are either 1 or 2. I know it could be done with Dijkstra's algorithm but I must use Breadth First Search. So far I have a working version of BFS that searches first for a vertex connected with an edge of weight 1. If it cannot find it, then returns a vertex connected with an edge of weight 2. After thinking about it, this is not the correct way to find the shortest path. The problem is I cannot think of any reasoning why BFS would work with weights 1 or 2, as opposed to any weight. Here is the code: public void addEdge(int start, int end, int weight) { adjMat[start][end] = 1; adjMat[end][start] = 1; edge_weight[start][end] = weight; edge_weight[end][start] = weight; } // ------------------------------------------------------------- public void bfs() // breadth-first search { // begin at vertex 0 vertexList[0].wasVisited = true; // mark it displayVertex(0); // display it theQueue.insert(0); // insert at tail int v2; while( !theQueue.isEmpty() ) // until queue empty, { int v1 = theQueue.remove(); // remove vertex at head // until it has no unvisited neighbors while( (v2=getAdjUnvisitedVertex(v1)) != -1 ){// get one, vertexList[v2].wasVisited = true; // mark it displayVertex(v2); // display it theQueue.insert(v2); // insert it } } // end while(queue not empty) // queue is empty, so we're done for(int j=0; j<nVerts; j++) // reset flags vertexList[j].wasVisited = false; } // end bfs() // ------------------------------------------------------------- // returns an unvisited vertex adj to v -- ****WITH WEIGHT 1**** public int getAdjUnvisitedVertex(int v) { for (int j = 0; j < nVerts; j++) if (adjMat[v][j] == 1 && vertexList[j].wasVisited == false && edge_weight[v][j] == 1){ //System.out.println("Vertex found with 1:"+ vertexList[j].label); return j; } for (int k = 0; k < nVerts; k++) if (adjMat[v][k] == 1 && vertexList[k].wasVisited == false && edge_weight[v][k] == 2){ //System.out.println("Vertex found with 2:"+vertexList[k].label); return k; } return -1; } // end getAdjUnvisitedVertex() // ------------------------------------------------------------- } //////////////////////////////////////////////////////////////// public class BFS{ public static void main(String[] args) { Graph theGraph = new Graph(); theGraph.addVertex('A'); // 0 (start for bfs) theGraph.addVertex('B'); // 1 theGraph.addVertex('C'); // 2 theGraph.addEdge(0, 1,2); // AB theGraph.addEdge(1, 2,1); // BC theGraph.addEdge(2, 0,1); // AD System.out.print("Visits: "); theGraph.bfs(); // breadth-first search System.out.println(); } // end main() } The problem then is, that I don't know why BFS can work for the shortest path problem with edges of weight 1 or 2 as opposed to any edges of any weight. Any help is appreciated. Thanks!

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  • Use format strings that contain %1, %2 etc. instead of %d, %s etc. - Linux, C++

    - by rursw1
    Hello, As a follow-up of this question (Message compiler replacement in Linux gcc), I have the following problem: When using MC.exe on Windows for compiling and generating messages, within the C++ code I call FormatMessage, which retrieves the message and uses the va_list *Arguments parameter to send the varied message arguments. For example: messages.mc file: MessageId=1 Severity=Error SymbolicName=MULTIPLE_MESSAGE_OCCURED Language=English message %1 occured %2 times. . C++ code: void GetMsg(unsigned int errCode, wstring& message,unsigned int paramNumber, ...) { HLOCAL msg; DWORD ret; LANGID lang = GetUserDefaultLangID(); try { va_list argList; va_start( argList, paramNumber ); const TCHAR* dll = L"MyDll.dll"; _hModule = GetModuleHandle(dll); ret =::FormatMessage( FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_HMODULE|FORMAT_MESSAGE_IGNORE_INSERTS, _hModule, errCode, lang, (LPTSTR) &msg, 0, &argList ); if ( 0 != ret ) { unsigned int count = 0 ; message = msg; if (paramNumber>0) { wstring::const_iterator iter; for (iter = message.begin();iter!=message.end();iter++) { wchar_t xx = *iter; if (xx ==L'%') count++; } } if ((count == paramNumber) && (count >0)) { ::LocalFree( msg ); ret =::FormatMessage( FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_HMODULE, _hModule, errCode, GetUserDefaultLangID(), (LPTSTR) &msg, 0, &argList ); } else if (count != paramNumber) { wstringstream tmp; wstring messNumber; tmp << (errCode & 0xFFFF); tmp >> messNumber; message = message +L"("+ messNumber + L"). Bad Format String. "; } } ::LocalFree( msg ); } catch (...) { message << L"last error: " << GetLastError(); } va_end( argList ); } Caller code: wstring message; GetMsg(MULTIPLE_MESSAGE_OCCURED, message,2, "Error message", 5); Now, I wrote a simple script to generate a .msg file from the .mc file, and then I use gencat to generate a catalog from it. But is there a way to use the formatted strings as they contain %1, %2, etc. and NOT the general (%d, %s...) format? Please note, that the solution has to be generic enough for each possible message with each posible types\ arguments order... Is it possible at all? Thank you.

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  • template pass by const reference

    - by 7vies
    Hi, I've looked over a few similar questions, but I'm still confused. I'm trying to figure out how to explicitly (not by compiler optimization etc) and C++03-compatible avoid copying of an object when passing it to a template function. Here is my test code: #include <iostream> using namespace std; struct C { C() { cout << "C()" << endl; } C(const C&) { cout << "C(C)" << endl; } ~C() { cout << "~C()" << endl; } }; template<class T> void f(T) { cout << "f<T>" << endl; } template<> void f(C c) { cout << "f<C>" << endl; } // (1) template<> void f(const C& c) { cout << "f<C&>" << endl; } // (2) int main() { C c; f(c); return 0; } (1) accepts the object of type C, and makes a copy. Here is the output: C() C(C) f<C> ~C() ~C() So I've tried to specialize with a const C& parameter (2) to avoid this, but this simply doesn't work (apparently the reason is explained in this question). Well, I could "pass by pointer", but that's kind of ugly. So is there some trick that would allow to do that somehow nicely? EDIT: Oh, probably I wasn't clear. I already have a templated function template<class T> void f(T) {...} But now I want to specialize this function to accept a const& to another object: template<> void f(const SpecificObject&) {...} But it only gets called if I define it as template<> void f(SpecificObject) {...}

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  • help me to choose the best soulotion for my purpose to build my software.

    - by rima
    before answer me plz thinking about the futures of these kind of program and answer me plz. I wanna get some data from oracle server like: 1-get all the function,package,procedure and etc for showing them or drop them & etc... 2-compile my *.sql files,get the result if they have problem & etc... becuz I was beginner in oracle first of all I for solve the second problem I try to connect to sqlPlus by RUN sqlplus and trace the output(I mean,I change the output stream of shell and trace what happend and handle the assigned message to customer. NOW THIS PART SUCCEED. just a little bit I have problem with get all result because the output is asynchronous.any way... [in this case I log in to oracle Server by send argument to the sqlplus by make a process in c#] after that I try to get all function,package or procedure name,but I have problem in speed!so I try to use oracle.DataAccess.dll to connect the database. now I m so confusing about: which way is correct way to build a program that work like Oracle Developer! I do not have any experience for like these program how work. If Your answer is I must use the second way follow this part plz: I search a little bit the Golden,PLedit (Benthic software),I have little bit problem how I must create the connection string?because I thinking about how I can find the host name or port number that oracle work on them?? am I need read the TNSNames.Ora file? IF your answer is I must use the first way follow this part plz: do u have any Idea for how I parse the output?because for example the result of a table is so confusing...[i can handle & program it but I really need someone experience,because the important things to me learn how such software work so nice and with quick response?] All of the has different style in output... If you are not sure Can u help me which book can help me in this way i become expert? becuz for example all the C# write just about how u can connect to DB and the DB books write how u can use this DB program,I looking for a book that give me some Idea how develop an interface for do transaction between these two.not simple send and receive data,for example how write a compiler for them. the language of book is not different for me i know C#,java,VB,sql,Oracle Thanks.

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  • My UITabBarController isn't appearing, but its first view is?

    - by E-Madd
    I've done some reorganizing of my project recently and now I'm not seeing my tab bar controller, but its first view controller's view is appearing. Here's a breakdown of everything that happens prior to the problem. App Delegate loads FirstViewController with nib. FirstViewController loads the application data from my server and then presents MainViewController with a modal transition. MainViewController is where the UITabBarController is supposed to be appearing. It's a very simple class. The .h @interface MainViewController : UIViewController <UITabBarControllerDelegate> { IBOutlet UITabBarController *tabBarController; } @property (nonatomic, retain) UITabBarController *tabBarController; @end The .m @implementation MainViewController @synthesize tabBarController; - (void)viewDidLoad { NSLog(@"MainViewController viewDidLoad"); //set tab bar controller delegate to self tabBarController.delegate = self; // home view HomeViewController *home = [[HomeViewController alloc] initWithTab]; // menu view MenuViewController *menu = [[MenuViewController alloc] initWithTab]; // special offers view SpecialOffersViewController *so = [[SpecialOffersViewController alloc] initWithTab]; // events view EventsViewController *events = [[EventsViewController alloc] initWithTab]; // info view InfoViewController *info = [[InfoViewController alloc] initWithTab]; //populate the tab bar controller with view controllers NSArray *controllers = [NSArray arrayWithObjects:home, menu, so, events, info, nil]; tabBarController.viewControllers = controllers; //release view controllers [home release]; [menu release]; [so release]; [events release]; [info release]; [controllers release]; //add tab bar controller to view [self.view addSubview:tabBarController.view]; [super viewDidLoad]; } and here's the bit from FirstViewController that modally presents the MainViewController... MainViewController *controller = [[MainViewController alloc] initWithNibName:@"MainViewController" bundle:nil]; controller.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal; [self presentModalViewController:controller animated:YES]; [controller release]; I'm not getting any compiler errors or warnings and the app runs swell... no crashing. It just isn't showing the darned TabBar, and it used to when I was creating it on my AppDelegate. I checked everything in my NIB and my outlets seem to be hooked up ok. I have no idea what's happened. Help!

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  • Implications of trying to double free memory space in C

    - by SidNoob
    Here' my piece of code: #include <stdio.h> #include<stdlib.h> struct student{ char *name; }; int main() { struct student s; s.name = malloc(sizeof(char *)); // I hope this is the right way... printf("Name: "); scanf("%[^\n]", s.name); printf("You Entered: \n\n"); printf("%s\n", s.name); free(s.name); // This will cause my code to break } All I know is that dynamic allocation on the 'heap' needs to be freed. My question is, when I run the program, sometimes the code runs successfully. i.e. ./struct Name: Thisis Myname You Entered: Thisis Myname I tried reading this I've concluded that I'm trying to double-free a piece of memory i.e. I'm trying to free a piece of memory that is already free? (hope I'm correct here. If Yes, what could be the Security Implications of a double-free?) While it fails sometimes as its supposed to: ./struct Name: CrazyFishMotorhead Rider You Entered: CrazyFishMotorhead Rider *** glibc detected *** ./struct: free(): invalid next size (fast): 0x08adb008 *** ======= Backtrace: ========= /lib/tls/i686/cmov/libc.so.6(+0x6b161)[0xb7612161] /lib/tls/i686/cmov/libc.so.6(+0x6c9b8)[0xb76139b8] /lib/tls/i686/cmov/libc.so.6(cfree+0x6d)[0xb7616a9d] ./struct[0x8048533] /lib/tls/i686/cmov/libc.so.6(__libc_start_main+0xe6)[0xb75bdbd6] ./struct[0x8048441] ======= Memory map: ======== 08048000-08049000 r-xp 00000000 08:01 288098 /root/struct 08049000-0804a000 r--p 00000000 08:01 288098 /root/struct 0804a000-0804b000 rw-p 00001000 08:01 288098 /root/struct 08adb000-08afc000 rw-p 00000000 00:00 0 [heap] b7400000-b7421000 rw-p 00000000 00:00 0 b7421000-b7500000 ---p 00000000 00:00 0 b7575000-b7592000 r-xp 00000000 08:01 788956 /lib/libgcc_s.so.1 b7592000-b7593000 r--p 0001c000 08:01 788956 /lib/libgcc_s.so.1 b7593000-b7594000 rw-p 0001d000 08:01 788956 /lib/libgcc_s.so.1 b75a6000-b75a7000 rw-p 00000000 00:00 0 b75a7000-b76fa000 r-xp 00000000 08:01 920678 /lib/tls/i686/cmov/libc-2.11.1.so b76fa000-b76fc000 r--p 00153000 08:01 920678 /lib/tls/i686/cmov/libc-2.11.1.so b76fc000-b76fd000 rw-p 00155000 08:01 920678 /lib/tls/i686/cmov/libc-2.11.1.so b76fd000-b7700000 rw-p 00000000 00:00 0 b7710000-b7714000 rw-p 00000000 00:00 0 b7714000-b7715000 r-xp 00000000 00:00 0 [vdso] b7715000-b7730000 r-xp 00000000 08:01 788898 /lib/ld-2.11.1.so b7730000-b7731000 r--p 0001a000 08:01 788898 /lib/ld-2.11.1.so b7731000-b7732000 rw-p 0001b000 08:01 788898 /lib/ld-2.11.1.so bffd5000-bfff6000 rw-p 00000000 00:00 0 [stack] Aborted So why is it that my code does work sometimes? i.e. the compiler is not able to detect at times that I'm trying to free an already freed memory. Has it got to do something with my stack/heap size?

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  • Windows API Programing....

    - by vs4vijay
    Hello There... Its me Vijay.. I m Trying to make a CrossHair(some kind of cursor) On The Screen while running a Game (Counter Strike)... so i did this... ############################# #include<iostream.h> #include<windows.h> #include<conio.h> #include<dos.h> #include<stdlib.h> #include<process.h> #include <time.h> int main() { HANDLE hl = OpenProcess(PROCESS_ALL_ACCESS,TRUE,pid); // Here pid is the process ID of the Game... HDC hDC = GetDC(NULL); //Here i pass NULL for Entire Screen... HBRUSH hb=CreateSolidBrush(RGB(0,255,255)); SelectObject(hDC,hb); POINT p; while(!kbhit()) { int x=1360/2,y=768/2; MoveToEx(hDC,x-20,y,&p); LineTo(hDC,x+20,y); SetPixel(hDC,x,y,RGB(255,0,0)); SetPixel(hDC,x-1,y-1,RGB(255,0,0)); SetPixel(hDC,x-1,y+1,RGB(255,0,0)); SetPixel(hDC,x+1,y+1,RGB(255,0,0)); SetPixel(hDC,x+1,y-1,RGB(255,0,0)); MoveToEx(hDC,x,y-20,&p); LineTo(hDC,x,y+20); } cin.get(); return 0; } #################################### it works fine....at desktop i see crosshair...but my problem is that when i run game...the cross here got disappeared.... so i think i did not handle the process of game... so i pass the HANDLE to the GetDC(hl)... But GetDC take only HWND(Handle To Window)... so i typecast it like this... HWND hl = (HWND)OpenProcess(PROCESS_ALL_ACCESS,TRUE,pid); and passed hl to the GetDC(hl)... but it doesnt work...Whats wrong with the code... plz tell me how do i make a simple shape at the screen on a process or game... PS : (My Compiler Is DevCPP and OS WinXP SP3....)

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