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  • Debugging MinGW program with gdb on Windows, not terminating at assert failure

    - by devil
    How do I set up gdb on window so that it does not allow a program with assertion failure to terminate? I intend to check the stack trace and variables in the program. For example, running this test.cpp program compiled with MinGW 'g++ -g test.cpp -o test' in gdb: #include <cassert> int main(int argc, char ** argv) { assert(1==2); return 0; } Gives: $ gdb test.exe GNU gdb 6.8 Copyright (C) 2008 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "i686-pc-mingw32"... (gdb) r Starting program: f:\code/test.exe [New thread 4616.0x1200] Error: dll starting at 0x77030000 not found. Error: dll starting at 0x75f80000 not found. Error: dll starting at 0x77030000 not found. Error: dll starting at 0x76f30000 not found. Assertion failed: 1==2, file test.cpp, line 2 This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information. Program exited with code 03. (gdb) I would like to be able to stop the program from terminating immediately, like how Visual Studio's debugger and gdb on Linux does it. I have done a search and found some stuff on trapping signals but I can't seem to find a good post on how to set up gdb to do this.

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  • including tk.h and tcl.h in c program

    - by user362075
    hi, i am working on an ubuntu system. My aim is to basically make an IDE in C language using GUI tools from TCL/TK. I installed tcl 8.4, tk8.4, tcl8.4-dev, tk8.4-dev and have the tk.h and tcl.h headers file in my system. But, when I am running a basic hello world program it's showing a hell lot of errors. include "tk.h" include "stdio.h" void hello() { puts("Hello C++/Tk!"); } int main(int, char *argv[]) { init(argv[0]); button(".b") -text("Say Hello") -command(hello); pack(".b") -padx(20) -pady(6); } Some of the errors are tkDecls.h:644: error: expected declaration specifiers before ‘EXTERN’ /usr/include/libio.h:488: error: expected ‘)’ before ‘*’ token In file included from tk.h:1559, from new1.c:1: tkDecls.h:1196: error: storage class specified for parameter ‘TkStubs’ tkDecls.h:1201: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘attribute’ before ‘*’ token /usr/include/stdio.h:145: error: storage class specified for parameter ‘stdin’ tk.h:1273: error: declaration for parameter ‘Tk_PhotoHandle’ but no such parameter Can anyone please tell me how can I rectify these errors? Please help...

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  • including tk.h and tcl.h in c program

    - by user362075
    hi, i am working on an ubuntu system. My aim is to basically make an IDE in C language using GUI tools from TCL/TK. I installed tcl 8.4, tk8.4, tcl8.4-dev, tk8.4-dev and have the tk.h and tcl.h headers file in my system. But, when I am running a basic hello world program it's showing a hell lot of errors. include "tk.h" include "stdio.h" void hello() { puts("Hello C++/Tk!"); } int main(int, char *argv[]) { init(argv[0]); button(".b") -text("Say Hello") -command(hello); pack(".b") -padx(20) -pady(6); } Some of the errors are tkDecls.h:644: error: expected declaration specifiers before ‘EXTERN’ /usr/include/libio.h:488: error: expected ‘)’ before ‘*’ token In file included from tk.h:1559, from new1.c:1: tkDecls.h:1196: error: storage class specified for parameter ‘TkStubs’ tkDecls.h:1201: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘attribute’ before ‘*’ token /usr/include/stdio.h:145: error: storage class specified for parameter ‘stdin’ tk.h:1273: error: declaration for parameter ‘Tk_PhotoHandle’ but no such parameter Can anyone please tell me how can I rectify these errors? Please help...

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  • How does virtual inheritance solve the diamond problem?

    - by cambr
    class A { public: void eat(){ cout<<"A";} }; class B: virtual public A { public: void eat(){ cout<<"B";} }; class C: virtual public A { public: void eat(){ cout<<"C";} }; class D: public B,C { public: void eat(){ cout<<"D";} }; int main(){ A *a = new D(); a->eat(); } I understand the diamond problem, and above piece of code does not have that problem. How exatly does virtual inheritance solve the problem? What I understand: When I say A *a = new D();, the compiler wants to know if an object of type D can be assigned to a pointer of type A, but it has two paths that it can follow, but cannot decide by itself. So, how does virtual inheritance resolve the issue (help compiler take the decision)?

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  • Hooking thread exit

    - by mackenir
    Is there a way for me to hook the exit of managed threads (i.e. run some code on a thread, just before it exits?) I've developed a mechanism for hooking thread exit that works for some threads. Step 1: develop a 'hook' STA COM class that takes a callback function and calls it in its destructor. Step 2: create a ThreadStatic instance of this object on the thread I want to hook, and pass the object a managed delegate converted to an unmanaged function pointer. The delegate then gets called on thread exit (since the CLR calls IUnknown::Release on all STA COM RCWs as part of thread exit). This mechanism works on, for example, worker threads that I create in code using the Thread class. However, it doesn't seem to work for the application's main thread (be it a console or windows app). The 'hook' COM object seems to be deleted too late in the shutdown process and the attempt to call the delegate fails. (The reason I want to implement this facility is so I can run some native COM code on the exiting thread that works with STA COM objects that were created on the thread, before it's 'too late' (i.e. before the thread has exited, and it's no longer possible to work with STA COM objects on that thread.))

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  • Ajax Autocompleteextender not showing the autocompletelist to choose

    - by subash
    i was working ajax auto completeextender witha text box in asp.net and c#.net. i am not able to get list to choose ,i have the appropriate web service method called..can anyone guide me to get the automo complete done. <form id="form1" runat="server"> <asp:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server"> </asp:ToolkitScriptManager> <div> <asp:AutoCompleteExtender runat="server" ID="autoComplete1" TargetControlID="TextBox1" ServiceMethod="GetCompletionList" ServicePath="AutoComplete.asmx" MinimumPrefixLength="0" CompletionInterval="50" EnableCaching="true" CompletionSetCount="1" DelimiterCharacters=";, :" ShowOnlyCurrentWordInCompletionListItem="true"> </asp:AutoCompleteExtender> <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox> </div> </form> and the web service method contains the following code [WebService(Namespace = "http://tempuri.org/")] [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] [System.ComponentModel.ToolboxItem(false)] [ScriptService] // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. // [System.Web.Script.Services.ScriptService] public class AutoComplete : System.Web.Services.WebService { [WebMethod] public string HelloWorld() { return "Hello World"; } [WebMethod] public string[] GetCompletionList(string prefixText, int count) { List<string> responses = new List<string>(); for (int i = 0; i < count; i++) responses.Add(prefixText + (char)(i + 65)); return responses.ToArray(); } }

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  • Compiler optimization causing the performance to slow down

    - by aJ
    I have one strange problem. I have following piece of code: template<clss index, class policy> inline int CBase<index,policy>::func(const A& test_in, int* srcPtr ,int* dstPtr) { int width = test_in.width(); int height = test_in.height(); double d = 0.0; //here is the problem for(int y = 0; y < height; y++) { //Pointer initializations //multiplication involving y //ex: int z = someBigNumber*y + someOtherBigNumber; for(int x = 0; x < width; x++) { //multiplication involving x //ex: int z = someBigNumber*x + someOtherBigNumber; if(soemCondition) { // floating point calculations } *dstPtr++ = array[*srcPtr++]; } } } The inner loop gets executed nearly 200,000 times and the entire function takes 100 ms for completion. ( profiled using AQTimer) I found an unused variable double d = 0.0; outside the outer loop and removed the same. After this change, suddenly the method is taking 500ms for the same number of executions. ( 5 times slower). This behavior is reproducible in different machines with different processor types. (Core2, dualcore processors). I am using VC6 compiler with optimization level O2. Follwing are the other compiler options used : -MD -O2 -Z7 -GR -GX -G5 -X -GF -EHa I suspected compiler optimizations and removed the compiler optimization /O2. After that function became normal and it is taking 100ms as old code. Could anyone throw some light on this strange behavior? Why compiler optimization should slow down performance when I remove unused variable ? Note: The assembly code (before and after the change) looked same.

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  • Use of for_each on map elements

    - by Antonio
    I have a map where I'd like to perform a call on every data type object member function. I yet know how to do this on any sequence but, is it possible to do it on an associative container? The closest answer I could find was this: Boost.Bind to access std::map elements in std::for_each. But I cannot use boost in my project so, is there an STL alternative that I'm missing to boost::bind? If not possible, I thought on creating a temporary sequence for pointers to the data objects and then, call for_each on it, something like this: class MyClass { public: void Method() const; } std::map<int, MyClass> Map; //... std::vector<MyClass*> Vector; std::transform(Map.begin(), Map.end(), std::back_inserter(Vector), std::mem_fun_ref(&std::map<int, MyClass>::value_type::second)); std::for_each(Vector.begin(), Vector.end(), std::mem_fun(&MyClass::Method)); It looks too obfuscated and I don't really like it. Any suggestions?

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  • Concat LPSTR in C++

    - by Cat Man Do
    Trying to use as basic C++ as I can to build a list of numbers from 1-52 in a random order (deck of cards). Unfortauntely, all my attempts to concat the strings and get a result end in failure. Any suggestions? NOTE: This is not homework it's something I'm using to create a game. // Locals char result[200] = ""; // Result int card[52]; // Array of cards srand(time(0)); // Initialize seed "randomly" // Build for (int i=0; i<52; i++) { card[i] = i; // fill the array in order } // Shuffle cards for (int i=0; i<(52-1); i++) { int r = i + (rand() % (52-i)); int temp = card[i]; card[i] = card[r]; card[r] = temp; } // Build result for (int c=0; c<52; c++) { // Build sprintf(result, "%d", card[c]); // Comma? if ( c < 51 ) { sprintf(result, "%s", ","); } } My end result is always garbled text. Thanks for the help.

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  • Weird switch behavior in .NET 4

    - by RaYell
    I have a problem understanding what's causes the compilation error in the code below: static class Program { static void Main() { dynamic x = ""; var test = foo(x); if (test == "test") { Console.WriteLine(test); } switch (test) { case "test": Console.WriteLine(test); break; } } private static string foo(object item) { return "bar"; } } The error I get is in switch (test) line: A switch expression or case label must be a bool, char, string, integral, enum, or corresponding nullable type. Intellisence shows me that foo operation will be resolved on runtime, which is fine because I'm using a dynamic type as a param. However I don't understand how if condition compiles fine when switch doesn't. Code above is just simplified version of what I have in my application (VSTO) which appeared after migrating the app from VSTO3 to VSTO4 when one method in VSTO was changed to return dynamic type values instead of object. Can anyone give me an explanation what's the problem. I know how to resolve it but I'd like to understand what's happening.

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  • Simple Java calculator

    - by Kevin Duke
    Firstly this is not a homework question. I am practicing my knowledge on java. I figured a good way to do this is to write a simple program without help. Unfortunately, my compiler is telling me errors I don't know how to fix. Without changing much logic and code, could someone kindly point out where some of my errors are? Thanks import java.lang.*; import java.util.*; public class Calculator { private int solution; private int x; private int y; private char operators; public Calculator() { solution = 0; Scanner operators = new Scanner(System.in); Scanner operands = new Scanner(System.in); } public int addition(int x, int y) { return x + y; } public int subtraction(int x, int y) { return x - y; } public int multiplication(int x, int y) { return x * y; } public int division(int x, int y) { solution = x / y; return solution; } public void main (String[] args) { System.out.println("What operation? ('+', '-', '*', '/')"); System.out.println("Insert 2 numbers to be subtracted"); System.out.println("operand 1: "); x = operands; System.out.println("operand 2: "); y = operands.next(); switch(operators) { case('+'): addition(operands); operands.next(); break; case('-'): subtraction(operands); operands.next(); break; case('*'): multiplication(operands); operands.next(); break; case('/'): division(operands); operands.next(); break; } } }

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  • Haskell Linear Algebra Matrix Library for Arbitrary Element Types

    - by Johannes Weiß
    I'm looking for a Haskell linear algebra library that has the following features: Matrix multiplication Matrix addition Matrix transposition Rank calculation Matrix inversion is a plus and has the following properties: arbitrary element (scalar) types (in particular element types that are not Storable instances). My elements are an instance of Num, additionally the multiplicative inverse can be calculated. The elements mathematically form a finite field (??2256). That should be enough to implement the features mentioned above. arbitrary matrix sizes (I'll probably need something like 100x100, but the matrix sizes will depend on the user's input so it should not be limited by anything else but the memory or the computational power available) as fast as possible, but I'm aware that a library for arbitrary elements will probably not perform like a C/Fortran library that does the work (interfaced via FFI) because of the indirection of arbitrary (non Int, Double or similar) types. At least one pointer gets dereferenced when an element is touched (written in Haskell, this is not a real requirement for me, but since my elements are no Storable instances the library has to be written in Haskell) I already tried very hard and evaluated everything that looked promising (most of the libraries on Hackage directly state that they wont work for me). In particular I wrote test code using: hmatrix, assumes Storable elements Vec, but the documentation states: Low Dimension : Although the dimensionality is limited only by what GHC will handle, the library is meant for 2,3 and 4 dimensions. For general linear algebra, check out the excellent hmatrix library and blas bindings I looked into the code and the documentation of many more libraries but nothing seems to suit my needs :-(. Update Since there seems to be nothing, I started a project on GitHub which aims to develop such a library. The current state is very minimalistic, not optimized for speed at all and only the most basic functions have tests and therefore should work. But should you be interested in using or helping out developing it: Contact me (you'll find my mail address on my web site) or send pull requests.

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  • TableView Cells unresponsive

    - by John Donovan
    I have a TableView and I wish to be able to press several cells one after the other and have messages appear. At the moment the cells are often unresponsive. I found some coed for a similar problem someone was kind enough to post, however, although he claimed it worked 100% it doesn't work for me. The app won't even build. Here's the code: -(UIView*) hitTest:(CGPoint)point withEvent:(UIEvent*)event { // check to see if the hit is in this table view if ([self pointInside:point withEvent:event]) { UITableViewCell* newCell = nil; // hit is in this table view, find out // which cell it is in (if any) for (UITableViewCell* aCell in self.visibleCells) { if ([aCell pointInside:[self convertPoint:point toView:aCell] withEvent:nil]) { newCell = aCell; break; } } // if it touched a different cell, tell the previous cell to resign // this gives it a chance to hide the keyboard or date picker or whatever if (newCell != activeCell) { [activeCell resignFirstResponder]; self.activeCell = newCell; // may be nil } } // return the super's hitTest result return [super hitTest:point withEvent:event]; } With this code I get this warning: that my viewController may not respond to pointsInside:withEvent (it's a TableViewController). I also get some faults: request for member 'visibleCells' in something not a structure or a union. incompatible type for argument 1 of pointInsideWithEvent, expression does not have a valid object type and similar. I must admit I'm not so good at reading other people's code but I was wondering whether the problems here are obvious and if so if anyone could give me a pointer it would be greatly appreciated.

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  • My button background seems stretched.

    - by Kyle Sevenoaks
    Hi, I have a button as made for you to see here. Looks fine,right? Well on the live site, euroworker.no/shipping it seems stretched. Renders fine in Chrome, IE and Safari, I thought it might have been a FF issue, but loaded the fiddle into FF and seems fine. Quick ref CSS and html: #fortsett_btn { background-image: url(http://euroworker.no/public/upload/fortsett.png?1269434047); background-repeat:no-repeat; background-position:left; background-color:none; border:none; outline;none; visibility: visible; position: relative; z-index: 2; width: 106px; height: 25px; cursor:pointer; }? And HTML <button type="submit" class="submit" id="fortsett_btn" title="Fortsett" value="">&nbsp;</button>? I wonder what's up with it.

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  • segmentation fault on Unix - possible stack corruption

    - by bob
    hello, i'm looking at a core from a process running in Unix. Usually I can work my around and root into the backtrace to try identify a memory issue. In this case, I'm not sure how to proceed. Firstly the backtrace only gives 3 frames where I would expect alot more. For those frames, all the function parameters presented appears to completely invalid. There are not what I would expect. Some pointer parameters have the following associated with them - Cannot access memory at address Would this suggest some kind of complete stack corruption. I ran the process with libumem and all the buffers were reported as being clean. umem_status reported nothing either. so basically I'm stumped. What is the likely causes? What should I look for in code since libumem appears to have reported no errors. Any suggestions on how I can debug furhter? any extra features in mdb I should consider? thank you.

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  • Do overlays/tooltips work correctly in Emacs for Windows?

    - by Cheeso
    I'm using Flymake on C# code, emacs v22.2.1 on Windows. The Flymake stuff has been working well for me. For those who don't know, you can read an overview of flymake, but the quick story is that flymake repeatedly builds the source file you are currently working on in the background, for the purpose of doing syntax checking. It then highlights the compiler warnings and erros in the current buffer. Flymake didn't work for C# initially, but I "monkey-patched it" and it works nicely now. If you edit C# in emacs, I highly recommend using flymake. The only problem I have is with the UI. Flymake highlights the errors and warnings nicely, and then inserts "overlays" with the full error or warning text. IF I hover the mouse pointer over the highlighted line in code, the overlay pops up. But as you can see, the overlay (tooltip) is truncated, and it doesn't display correctly. Flymake seems to be doing the right thing, it's the overlay part that seems broken., and overlay seems to do the right thing. It's the tooltip that is displayed incorrectly. Do overlays tooltips work correctly in emacs for Windows? Where do I look to fix this?

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  • iPhone app crashes on start-up, in stack-trace only messages from built-in frameworks

    - by Aleksejs
    My app some times crashes at start-up. In stack-trace only messages from built-in frameworks. An excerpt from a crash log: OS Version: iPhone OS 3.1.3 (7E18) Report Version: 104 Exception Type: EXC_BAD_ACCESS (SIGBUS) Exception Codes: KERN_PROTECTION_FAILURE at 0x000e6000 Crashed Thread: 0 Thread 0 Crashed: 0 CoreGraphics 0x339305d8 argb32_image_mark_RGB32 + 704 1 CoreGraphics 0x338dbcd4 argb32_image + 1640 2 libRIP.A.dylib 0x320d99f0 ripl_Mark 3 libRIP.A.dylib 0x320db3ac ripl_BltImage 4 libRIP.A.dylib 0x320cc2a0 ripc_RenderImage 5 libRIP.A.dylib 0x320d5238 ripc_DrawImage 6 CoreGraphics 0x338d7da4 CGContextDelegateDrawImage + 80 7 CoreGraphics 0x338d7d14 CGContextDrawImage + 364 8 UIKit 0x324ee68c compositeCGImageRefInRect 9 UIKit 0x324ee564 -[UIImage(UIImageDeprecated) compositeToRect:fromRect:operation:fraction:] 10 UIKit 0x32556f44 -[UINavigationBar drawBackButtonBackgroundInRect:withStyle:pressed:] 11 UIKit 0x32556b00 -[UINavigationItemButtonView drawRect:] 12 UIKit 0x324ecbc4 -[UIView(CALayerDelegate) drawLayer:inContext:] 13 QuartzCore 0x311cacfc -[CALayer drawInContext:] 14 QuartzCore 0x311cab00 backing_callback 15 QuartzCore 0x311ca388 CABackingStoreUpdate 16 QuartzCore 0x311c978c -[CALayer _display] 17 QuartzCore 0x311c941c -[CALayer display] 18 QuartzCore 0x311c9368 CALayerDisplayIfNeeded 19 QuartzCore 0x311c8848 CA::Context::commit_transaction(CA::Transaction*) 20 QuartzCore 0x311c846c CA::Transaction::commit() 21 QuartzCore 0x311c8318 +[CATransaction flush] 22 UIKit 0x324f5e94 -[UIApplication _reportAppLaunchFinished] 23 UIKit 0x324a7a80 -[UIApplication _runWithURL:sourceBundleID:] 24 UIKit 0x324f8df8 -[UIApplication handleEvent:withNewEvent:] 25 UIKit 0x324f8634 -[UIApplication sendEvent:] 26 UIKit 0x324f808c _UIApplicationHandleEvent 27 GraphicsServices 0x335067dc PurpleEventCallback 28 CoreFoundation 0x323f5524 CFRunLoopRunSpecific 29 CoreFoundation 0x323f4c18 CFRunLoopRunInMode 30 UIKit 0x324a6c00 -[UIApplication _run] 31 UIKit 0x324a5228 UIApplicationMain 32 Journaler 0x000029ac main (main.m:14) 33 Journaler 0x00002948 start + 44 File main.m is simple as possible: #import <UIKit/UIKit.h> int main(int argc, char *argv[]) { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; int retVal = UIApplicationMain(argc, argv, nil, nil); // line 14 [pool release]; return retVal; } What my cause the app to crash?

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  • Better why of looping to detect change.

    - by Dremation
    As of now I'm using a while(true) method to detect changes in memory. The problem with this is it's kill the applications performance. I have a list of 30 pointers that need checked as rapidly as possible for changes, without sacrificing a huge performance loss. Anyone have ideas on this? memScan = new Thread(ScanMem); public static void ScanMem() { int i = addy.Length; while (true) { Thread.Sleep(30000); //I do this to cut down on cpu usage for (int j = 0; j < i; j++) { string[] values = addy[j].Split(new char[] { Convert.ToChar(",") }); //MessageBox.Show(values[2]); try { if (Memory.Scanner.getIntFromMem(hwnd, (IntPtr)Convert.ToInt32(values[0], 16), 32).ToString() != values[1].ToString()) { //Ok, it changed lets do our work //work if (Globals.Working) return; SomeFunction("Results: " + values[2].ToString(), "Memory"); Globals.Working = true; }//end if }//end try catch { } }//end for }//end while }//end void

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  • Does GC guarantee that cleared References are enqueued to ReferenceQueue in topological order?

    - by Dimitris Andreou
    Say there are two objects, A and B, and there is a pointer A.x --> B, and we create, say, WeakReferences to both A and B, with an associated ReferenceQueue. Assume that both A and B become unreachable. Intuitively B cannot be considered unreachable before A is. In such a case, do we somehow get a guarantee that the respective references will be enqueued in the intuitive (topological when there are no cycles) order in the ReferenceQueue? I.e. ref(A) before ref(B). I don't know - what if the GC marked a bunch of objects as unreachable, and then enqueued them in no particular order? I was reviewing Finalizer.java of guava, seeing this snippet: private void cleanUp(Reference<?> reference) throws ShutDown { ... if (reference == frqReference) { /* * The client no longer has a reference to the * FinalizableReferenceQueue. We can stop. */ throw new ShutDown(); } frqReference is a PhantomReference to the used ReferenceQueue, so if this is GC'ed, no Finalizable{Weak, Soft, Phantom}References can be alive, since they reference the queue. So they have to be GC'ed before the queue itself can be GC'ed - but still, do we get the guarantee that these references will be enqueued to the ReferenceQueue at the order they get "garbage collected" (as if they get GC'ed one by one)? The code implies that there is some kind of guarantee, otherwise unprocessed references could theoretically remain in the queue. Thanks

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  • Why `A & a = a` is valid?

    - by psaghelyi
    #include <iostream> #include <assert.h> using namespace std; struct Base { Base() : m_member1(1) {} Base(const Base & other) { assert(this != &other); // this should trigger m_member1 = other.m_member1; } int m_member1; }; struct Derived { Derived(Base & base) : m_base(m_base) {} // m_base(base) Base & m_base; }; void main() { Base base; Derived derived(base); cout << derived.m_base.m_member1 << endl; // crashes here } The above example is a synthesized version of a mistyped constructor. I used reference at the class member Derived::m_base because I wanted to make sure that the member will be initialized as the constructor had called. One problem is that nor GCC nor MSVC gives me a warning at m_base(m_base). But the more serious for me is that the assert finds everything fine and the application crashes later (sometimes far away from the mistake). Question: Is there any way to indicate such mistakes?

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  • Instantiating class with custom allocator in shared memory

    - by recipriversexclusion
    I'm pulling my hair due to the following problem: I am following the example given in boost.interprocess documentation to instantiate a fixed-size ring buffer buffer class that I wrote in shared memory. The skeleton constructor for my class is: template<typename ItemType, class Allocator > SharedMemoryBuffer<ItemType, Allocator>::SharedMemoryBuffer( unsigned long capacity ){ m_capacity = capacity; // Create the buffer nodes. m_start_ptr = this->allocator->allocate(); // allocate first buffer node BufferNode* ptr = m_start_ptr; for( int i = 0 ; i < this->capacity()-1; i++ ) { BufferNode* p = this->allocator->allocate(); // allocate a buffer node } } My first question: Does this sort of allocation guarantee that the buffer nodes are allocated in contiguous memory locations, i.e. when I try to access the n'th node from address m_start_ptr + n*sizeof(BufferNode) in my Read() method would it work? If not, what's a better way to keep the nodes, creating a linked list? My test harness is the following: // Define an STL compatible allocator of ints that allocates from the managed_shared_memory. // This allocator will allow placing containers in the segment typedef allocator<int, managed_shared_memory::segment_manager> ShmemAllocator; //Alias a vector that uses the previous STL-like allocator so that allocates //its values from the segment typedef SharedMemoryBuffer<int, ShmemAllocator> MyBuf; int main(int argc, char *argv[]) { shared_memory_object::remove("MySharedMemory"); //Create a new segment with given name and size managed_shared_memory segment(create_only, "MySharedMemory", 65536); //Initialize shared memory STL-compatible allocator const ShmemAllocator alloc_inst (segment.get_segment_manager()); //Construct a buffer named "MyBuffer" in shared memory with argument alloc_inst MyBuf *pBuf = segment.construct<MyBuf>("MyBuffer")(100, alloc_inst); } This gives me all kinds of compilation errors related to templates for the last statement. What am I doing wrong?

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  • How to mmap the stack for the clone() system call on linux?

    - by Joseph Garvin
    The clone() system call on Linux takes a parameter pointing to the stack for the new created thread to use. The obvious way to do this is to simply malloc some space and pass that, but then you have to be sure you've malloc'd as much stack space as that thread will ever use (hard to predict). I remembered that when using pthreads I didn't have to do this, so I was curious what it did instead. I came across this site which explains, "The best solution, used by the Linux pthreads implementation, is to use mmap to allocate memory, with flags specifying a region of memory which is allocated as it is used. This way, memory is allocated for the stack as it is needed, and a segmentation violation will occur if the system is unable to allocate additional memory." The only context I've ever heard mmap used in is for mapping files into memory, and indeed reading the mmap man page it takes a file descriptor. How can this be used for allocating a stack of dynamic length to give to clone()? Is that site just crazy? ;) In either case, doesn't the kernel need to know how to find a free bunch of memory for a new stack anyway, since that's something it has to do all the time as the user launches new processes? Why does a stack pointer even need to be specified in the first place if the kernel can already figure this out?

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  • Bitrate Switching in xml playlist not loading video

    - by James Williams
    Using JW Player ver 5.4 and JW Embedder. Plugins are grid by Dabbler and fbit (Facebook). The Bitrate switching is not working. Does work fine for one video with HTML5 Video tag. When more than one video, it only shows the first video pic. Works fine with no bitrate switching. Code - HTML5 <script type="text/javascript" src="jwplayer/jwplayer.js"></script> <video id="container"></div> <script type="text/javascript"> jwplayer("container").setup({ flashplayer: "jwplayer/player.swf", streamer: "rtmp://server/location/", playlistfile: "playlists/playlist.xml", plugins: { grid: { rows: 4, distance: 60, horizontalmargin: 75, verticalmargin: 75 }, fbit: { link: "http://www.domain.com" } }, height: 375, width: 850, dock: true }); </script> XML - ATOM/MEDIA xmlns:jwplayer='http://developer.longtailvideo.com/trac/wiki/FlashFormats' Demostration Playlist Video 1 rtmp rtmp://server/location/ Video 2 rtmp rtmp://server/location/ have tried it with both video and div tags for the container. Div tag just shows a blank video area and a Null exception on Line 1 char 1863, this is probably the jwplayer.js file. XML is larger than this, this is to give you a brief syntax of my code and xml. I have searched for over 6 hrs on both longtail and search engine searches. Thank you in advance.

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  • string parsing to double fails in C++ (Xcode problem?)

    - by helixed
    Here's a fun one I've been trying to figure out. I have the following program: #include <iostream> #include <string> #include <sstream> using namespace std; int main(int argc, char *argv[]) { string s("5"); istringstream stream(s); double theValue; stream >> theValue; cout << theValue << endl; cout << stream.fail(); } The output is: 0 1 I don't understand why this is failing. Could somebody please tell me what I'm doing wrong? Thanks, helixed EDIT: Okay, sorry to turn this into a double post, but this looks like a problem specific to Xcode. If I compile this in g++, the code works without a problem. Does anybody have an idea why this is happening in Xcode, and how I could possibly fix it? Thanks again, helixed

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  • sqlite3 no insert is done after --> insert into --> SQLITE_DONE

    - by Fra
    Hi all, I'm trying to insert some data in a table using sqlite3 on an iphone... All the error codes I get from the various steps indicate that the operation should have been successful, but in fact, the table remains empty...I think I'm missing something... here the code: sqlite3 *database = nil; NSString *dbPath = [[[ NSBundle mainBundle ] resourcePath ] stringByAppendingPathComponent:@"placemarks.sql"]; if(sqlite3_open([dbPath UTF8String], &database) == SQLITE_OK){ sqlite3_stmt *insert_statement = nil; //where int pk, varchar name,varchar description, blob picture static char *sql = "INSERT INTO placemarks (pk, name, description, picture) VALUES(99,'nnnooooo','dddooooo', '');"; if (sqlite3_prepare_v2(database, sql, -1, &insert_statement, NULL) != SQLITE_OK) { NSAssert1(0, @"Error: failed to prepare statement with message '%s'.", sqlite3_errmsg(database)); } int success = sqlite3_step(insert_statement); int finalized = sqlite3_finalize(insert_statement); NSLog(@"success: %i finalized: %i",success, finalized); NSAssert1(101, @"Error: failed to insert into the database with message '%s'.", sqlite3_errmsg(database)); sqlit3_step returns 101, so SQLITE_DONE, which should be ok.. If I execute the sql statement in the command line it works properly... anyone has an idea? could it be that there's a problem in writing the placemarks.sql because it's in the resources folder? rgds Fra

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