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  • Documentation concerning platform-specific macros in Linux/POSIX

    - by Nubok
    When compiling a C/C++ program under Windows using Visual Studio (or a compiler that tries to be compatible) there is a predefined macro _WIN32 (Source: http://msdn.microsoft.com/en-us/library/b0084kay.aspx) that you can use for platform-specific #ifdef-s. What I am looking for is an analogon under Linux: a macro which tells me that I am compiling for Linux/an OS that claims to be (more or less) POSIX-compatible. So I looked into gcc documentation and found this: http://gcc.gnu.org/onlinedocs/cpp/System_002dspecific-Predefined-Macros.html Applied to my program, the following macros (gcc 4.4.5 - Ubuntu 10.10) looked promising (I hope that I didn't drop an important macro): #define __USE_BSD 1 #define __unix__ 1 #define __linux 1 #define __unix 1 #define __linux__ 1 #define _POSIX_SOURCE 1 #define __STDC_HOSTED__ 1 #define __STDC_IEC_559__ 1 #define __gnu_linux__ 1 #define __USE_SVID 1 #define __USE_XOPEN2K 1 #define __USE_POSIX199506 1 #define _G_USING_THUNKS 1 #define __USE_XOPEN2K8 1 #define _BSD_SOURCE 1 #define unix 1 #define linux 1 #define __USE_POSIX 1 #define __USE_POSIX199309 1 #define __SSP__ 1 #define _SVID_SOURCE 1 #define _G_HAVE_SYS_CDEFS 1 #define __USE_POSIX_IMPLICITLY 1 Where do I find a detailed documentation of them - as to the mentioned Windows-specific macros above? Additionally I'd be interested in macros normally defined for other POSIX-compliant operating systems as *BSD etc.

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  • Debugging segfault on swig/python/c++

    - by Pradyot
    I am trying to figure out what the best way to debug a segault with swig/python/c++. A core file is being generated. I have a basic MessageFactory(defined in c++ that provides a simple interface to accept a few strings as input and return a string as output). This interface is then specified in a .i file. swig is used to generate Wrapper.cpp as well as a MessageFactory.py from the .i file. This along with supporting files is compiled into a dynamic lib. The point of failure , is when the MessageFactory is instantiated within python code. Any suggestions on how I can go about debugging this? I've tried running the script within pdb, what I know from that is import on the generated MessageFactory.py is whats causing the seg-fault.

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  • LockWorkStation - Compilation error - identifier not found

    - by Microkernel
    Hi All, I am writing an application in which I got to lock the computer screen (OS is Windows). My Application is in C++. For this purpose I used the LockWorkStation() API defined on msdn, http://msdn.microsoft.com/en-us/library/aa376875%28VS.85%29.aspx I have included windows.h as told but still I am getting compilation error: .\source.cpp(5) : error C3861: 'LockWorkStation': identifier not found here is a sample code thats giving error. #include <Windows.h> int main() { LockWorkStation(); return 0; } Please tell me what I am missing here :( I am using MS-Visual studio 2005. Regards.

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  • Function matching in Qt

    - by Alexander
    Hello, I have some trouble with Qt. I have a class 'Core' class Core { public: static QString get_file_content(QString filename); static void setMainwindow(MainWindow *w); private: static MainWindow *main_window; }; and class 'MainWindow' in namespace Ui: namespace Ui { class MainWindow; } class MainWindow : public QMainWindow { Q_OBJECT public: MainWindow(QWidget *parent = 0); ~MainWindow(); private: Ui::MainWindow *ui; }; In MainWindow constructor I make MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) { ui->setupUi(this); Core::setMainwindow(this); } and gets error mainwindow.cpp:8: error: no matching function for call to 'Core::setMainwindow(MainWindow* const)' Of cource, i include core.h with declaration of 'Core' class. That's occurs only on setMainwindow method. So the questions is - why Core class method setMainwindow() is invisible in MainWindow class?

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  • forward declare static function c++

    - by Matthew Scouten
    I want to forward declare a static member function of a class in another file. What I WANT to do looks like this: BigMassiveHeader.h: class foo { static void init_foos(); } Main.cpp: class foo; void init_foos(); int main(char** argv, int argc) { foo::init_foos() } This fails out with "error C2027: use of undefined type 'tt_py_ns::foo'" Is there a way to accomplish what I want to do with out making init_foos a free function, or including BigMassiveHeader.h? (BigMassiveHeader.h is noticeably effecting compile time, and is included everywhere.)

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  • how to implement OOP using QT

    - by kaycee
    hi, this is a simple OOP QT question. my app consists of main window (QMainWindow) and a table (QTableWidget). in the main window i have arguments and variables which i would like to pass to the table class, and to access methods in main widnow class from the table class, how should i do it ? mainwindow.h class MainWindow : public QMainWindow { Q_OBJECT private: int a; int b; Spreadsheet *spreadsheet; public: void set_a(int); void set_b(int); spreadsheet.h class Spreadsheet : public QTableWidget { Q_OBJECT public: Spreadsheet(QWidget *parent = 0); atm i define Spreadsheet like this: spreadsheet = new Spreadsheet(this); and i'd like to access set_a() from spreadsheet.cpp...

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  • No whitespace between a cast and a namespace operator?

    - by Pod
    Hello. Could anyone please explain the following line of code, found on http://docs.openttd.org/ai__cargo_8cpp_source.html return (AICargo::TownEffect)::CargoSpec::Get(cargo_type)->town_effect; If this line was: return (AICargo::TownEffect) ::CargoSpec::Get(cargo_type)->town_effect; (note the space between TownEffect) and the ::) then I would understand it fine. However there is no whitespace in that document*, which would mean (AICargo::TownEffect) is the left operand of the :: operator. How does this code work/compile? Or are the two things equivilent due to some obscure C++ rule? *It's the same in the cpp file as well.

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  • I need a simple Example of JNA which can map char * of c dll.

    - by Vikas Sharma
    I have one dll of cpp and i need to call its function which returns char*. Im using String in native Declaration but getting out put like ???? or some crap thing. I just want to knw that do i have to decode the String.i have already set my system property like System.setProperty("jna.encoding","UTF-8"); Im in big mess. Hope to get Some Positive replies from u guys. Thanks in Advance.. Cheers...!

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  • Android ndk build mysteriously failing under cygwin with "Error 126"

    - by Jan Hudec
    I have a JNI application built by ndk-build (using Android NDK r5b and cygwin make 3.81). The build usually works, by occasionally fails with: ... Compile++ thumb : components <= Component.cpp make: *** [/c/.hudson/jobs/Nightly/workspace/application/obj/local/armeabi/objs/components/Component.o] Error 126 make: Leaving directory `/c/.hudson/jobs/Nightly/workspace/application/obj/local/armeabi/objs/components' There is no other error. Make than exits with status 2. It happens in different file each time (the name above is anonymized). It seems to happen more often with parallel builds, but sometimes happens with non-parallel builds too. Does anybody have an idea what it might be or at least how to debug it?

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  • boost::dynamic_pointer_cast with const pointer not working ?

    - by ereOn
    Hi, Let's say I have two classes, A and B, where B is a child class of A. I also have the following function: void foo(boost::shared_ptr<const A> a) { boost::shared_ptr<const B> b = boost::dynamic_pointer_cast<const B>(a); // Error ! } Compilation with gcc gives me the following errors: C:\Boost\include/boost/smart_ptr/shared_ptr.hpp: In constructor 'boost::shared_ptr< <template-parameter-1-1> >::shared_ptr(const boost::shared_ptr<Y>&, boost::detail::dynamic_cast_tag) [with Y = const A, T = const B]': C:\Boost\include/boost/smart_ptr/shared_ptr.hpp:522: instantiated from 'boost::shared_ptr<X> boost::dynamic_pointer_cast(const boost::shared_ptr<U>&) [with T = const B, U = const A]' src\a.cpp:10: instantiated from here C:\Boost\include/boost/smart_ptr/shared_ptr.hpp:259: error: cannot dynamic_cast 'r->boost::shared_ptr<const A>::px' (of type 'const class A* const') to type 'const class B*' (source type is not polymorphic) What could possibly be wrong ? Thank you.

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  • How to change *.ico for button in running mode?

    - by karikari
    I am currently doing visual c++ for an Internet Explorer toolbar button. I have a registration script file (*.rgs) that defines or maybe register the features of my button inside the Windows registry. My objective is, I want my button to change its *.ico image, based on certain conditions process from my *.cpp file. My problem is, I don't understand, how can I somehow change the *.ico file for my button in real time, during my application is running? For example, IF f = 1, ico_file = green.ico; ELSE ico_file = red.ico; Any idea, that you guys can point to me, how can I change the *.ico file for my Internet Explorer toolbar button while the IE is running.

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  • wxWidgets errors occur after upgrading gDEBugger

    - by acekiller
    all. Today I upgraded my gDEBugger (though I don't think it involves gDEBugger) to the latest version but problem occurs. When I tried to open gDEBugger, an alert window named "wxWidgets Debug Alert" pop-up, reporting that "....\src\common\xpmdecod.cpp(822):assert "i==colors_cnt" failed in wxXPMDecoder::ReadData(). Call stack: [00]wxConsole....balabala....", like follows. All these words seem just like warnings and didn't affect the following work, however I am wondering why this problem occurs? What's the root cause? I am not familiar with wxWidgets and hopes those guru on it can help me resolve it.

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  • Passing user context to from impersonated thread to outproc COM object

    - by Thumbeti
    Hi, I am writing a CPP program on windows 2k3 where i want to achieve the following thing. Pass the user context from the impersonated thread to a outproc COM component. Steps what i m trying in details are: 1) Start an execution of exe with user USR1 2) Impersonate the current thread with USR2 3) Initiate a API on outproc COM object. And this COM object should run with USR2 What is happening: on 3rd step, COM object is getting started with USR1 only. Can anybody help me in passing the user context to COM object. Thanks in advance, Thumbeti

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  • jstring to L_TCHAR* format

    - by Ayusman
    Hi All, I have been trying to call a C function that has the following signature int changeFoo(L_TCHAR* pszFileSrc){....} in my JNI call my method looks like this: JNIEXPORT jint JNICALL Java_com_me_L_AFoo (JNIEnv * env, jclass jclass, jstring pSrc) { jint retValue = -100; retValue = changeFoo(pSrc); return retValue; } I get the following error in visual studio. Error 1 error C2664: 'L_FileConvert' : cannot convert parameter 1 from 'jstring' to 'L_TCHAR *' c:\Ayusman\Work\MyVCpp\LTExampleDll\LTExampleDll\LTExampleMain.cpp 46 LTExampleDll When I looked at the definition of L_TCHAR * here is what I got in the header files (in that sequence): typedef TCHAR L_TCHAR; typedef WCHAR TCHAR,*PTCHAR; typedef wchar_t WCHAR; //wc, 16 bit UNICODE char I work on java, this is a JNI application that I am trying to build. Can any body help as to how can I convert this properly? Thanks, Ayusman

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  • argv[1] loadImage problem xcode 3.2 and snow leopard

    - by ignacionieto
    Hi Im on mac snow leopard and test these code on xcode3.2 of the Learning OpenCV everything works fine but the image doesnt appear and in the windows. I had try to understand searching for two days what does argv[1] means, but Im still no clear. Im a newbie en C++. I had the image in the same directory where the main.cpp is #include <OpenCV/cv.h> #include <OpenCV/highgui.h> int main(int argc, char** argv) { IplImage* interest_img; CvRect interest_rect; if( argc == 7 && ((interest_img= cvLoadImage( argv[1],1) ) != 0 )) { A more easy example is here: http://books.google.cl/books?id=seAgiOfu2EIC&pg=PA17&lpg=PA17&dq=cvLoadImage%28argv[1]&source=bl&ots=hRJ5bhkAOf&sig=gyYAqZBnS6lCCXJz9Fz7vzOsF-U&hl=es&ei=dvdvS-fWG8eWtgePy_WCBg&sa=X&oi=book_result&ct=result&resnum=6&ved=0CBwQ6AEwBTgK#v=onepage&q=cvLoadImage%28argv[1]&f=false both I have test it but they dont work. Please help me

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  • Hiding members in a C struct

    - by Marlon
    I've been reading about OOP in C but I never liked how you can't have private data members like you can in C++. But then it came to my mind that you could create 2 structures. One is defined in the header file and the other is defined in the source file. // ========================================= // in somestruct.h typedef struct { int _public_member; } SomeStruct; // ========================================= // in somestruct.cpp #include "somestruct.h" typedef struct { int _public_member; int _private_member; } SomeStructSource; SomeStruct *SomeStruct_Create() { SomeStructSource *p = (SomeStructSource *)malloc(sizeof(SomeStructSource)); p->_private_member = 0xWHATEVER; return (SomeStruct *)p; } From here you can just cast one structure to the other. Is this considered bad practice? Or is it done often? (I think this is done with a lot of the structures when using the Win32 API, but you guys are the experts let me know!)

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  • Singleton class issue in Qt

    - by sijith
    i created a singleton class and trying to access that class in other class but getting error "cannot access private member" Setupconfig is my singleton class and i am trying to access this class in other class which have QMainWindow Error 'Setupconfig::Setupconfig' : cannot access private member declared in class 'Setupconfig' ///////////////////////////////////////////////////////////////////// Setupconfig.h static Setupconfig *buiderObj() { static Setupconfig *_setupObj= new Setupconfig(); return _setupObj; } private: Setupconfig(); ////////////////////////////////////// EasyBudget.h class EasyBudget : public QMainWindow, public Ui::EasyBudgetClass, public Setupconfig { Q_OBJECT public: Setupconfig *setupObj; } ////////////////////////////////////// EasyBudget.cpp EasyBudget::EasyBudget(QWidget *parent, Qt::WFlags flags) : QMainWindow(parent,Qt::FramelessWindowHint) { setupObj=Setupconfig::buiderObj(); }

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  • How to override environment variables when running configure?

    - by Sam
    In any major package for Linux, running ./configure --help will output at the end: Some influential environment variables: CC C compiler command CFLAGS C compiler flags LDFLAGS linker flags, e.g. -L<lib dir> if you have libraries in a nonstandard directory <lib dir> CPPFLAGS C/C++ preprocessor flags, e.g. -I<include dir> if you have headers in a nonstandard directory <include dir> CPP C preprocessor Use these variables to override the choices made by `configure' or to help it to find libraries and programs with nonstandard names/locations. How do I use these variables to include a directory? I tried running ./configure --CFLAGS="-I/home/package/custom/" and ./configure CFLAGS="-I/home/package/custom/" however these do not work. Any suggestions?

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  • Why is this default template parameter not allowed?

    - by Matt Joiner
    I have the following class: template <typename Type = void> class AlignedMemory { public: AlignedMemory(size_t alignment, size_t size) : memptr_(0) { int iret(posix_memalign((void **)&memptr_, alignment, size)); if (iret) throw system_error("posix_memalign"); } virtual ~AlignedMemory() { free(memptr_); } operator Type *() const { return memptr_; } Type *operator->() const { return memptr_; } //operator Type &() { return *memptr_; } //Type &operator[](size_t index) const; private: Type *memptr_; }; And attempt to instantiate an automatic variable like this: AlignedMemory blah(512, 512); This gives the following error: src/cpfs/entry.cpp:438: error: missing template arguments before ‘buf’ What am I doing wrong? Is void not an allowed default parameter?

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  • QT drawing without erasing widget

    - by faya
    Hello, If I have a derived object of QWidget class and on slot function in it I have an update(). here is some pseudocode: *.h slot: updateNow(); *.cpp constructor() { setPalllete(QPallete(QColor(250,250,200))); setAUtoFillBackground(true); } updateNow() { update(); } paintEvent() { QPainter painter(this); painter.drawRect(1,2,3,4); } So how should I don't get erased my pallete after update() call? P.S. - Sorry for my English and only pseudocode.

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  • llvm clang struct creating functions on the fly

    - by anon
    I'm using LLVM-clang on Linux. Suppose in foo.cpp I have: struct Foo { int x, y; }; How can I create a function "magic" such that: typedef (Foo) SomeFunc(Foo a, Foo b); SomeFunc func = magic("struct Foo { int x, y; };"); so that: func(SomeFunc a, SomeFunc b); // returns a.x + b.y; ? Note: So basically, "magic" needs to take a char*, have LLVM parse it to get how C++ lays out the struct, then create a function on the fly that returns a.x + b.y; Thanks!

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  • Visual c++ opencv 2.1 contains()

    - by kaushalyjain
    how to check whether a given point is contained in a rectangle using the contains() function in Rect_ construct... Please give me the exact function and its parameters.Like when i type this Point b(2,2); Rect a(10,10,50,50); cout<< Rect_::contains(b); There is a compile error saying 1c:\users\kaushal\documents\visual studio 2008\projects\test1\test1.cpp(23) : error C2352: 'cv::Rect_<Tp::contains' : illegal call of non-static member function 1c:\opencv2.1\include\opencv\cxcore.hpp(385) : see declaration of 'cv::Rect<_Tp::contains'

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  • Perforce "Locked client" error

    - by Thanatos
    I'm new to Perforce, and it is not going well at all. But currently, I am completely stuck, as all I can get it to say is: $ p4 open a_code_file.cpp Locked client 'my_hostname' can only be used by owner 'perforce'. I have absolutely no idea what I did to upset it, and the error message itself is meaningless gibberish to me. "perforce" doesn't own anything - all the files are owned by me. I am in a Perforce repository, ie, there's a .p4rc a few directories up. Edit: It only seems to be some files. If I: $ cd some_other_directory_in_the_repo $ p4 open a_file ... it works. So it's only some things...

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  • Linking Libraries in Xcode

    - by Dan
    Hey all, I'm using a powerbook (osx 10.5) and recently downloaded and installed FFTW 3.2 (link text). I've been able to compile and run some simple programs based on the online tutorial using the terminal: g++ main.cpp -lfftw3 -lm however, I can't get the same program to compile in Xcode. I get a linking error, "symbol(s) not found". There is a file called libfftw3.a in /usr/local/lib. How can this be linked? Furthermore, apparently the libraries have to be linked in a particular order, i.e. see: link text thanks for any help

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  • What is the most efficient way to find missing semicolons in VS with C++?

    - by Dr. Monkey
    What are the best strategies for finding that missing semicolon that's causing the error? Are there automated tools that might help. I'm currently using Visual Studio 2008, but general strategies for any environment would be interesting and more broadly useful. Background: Presently I have a particularly elusive missing semicolon (or brace) in a C++ program that is causing a C2143 error. My header file dependencies are fairly straightforward, but still I can't seem to find the problem. Rather than post my code and play Where's Wally (or Waldo, depending on where you're from) I thought it would be more useful to get some good strategies that can be applied in this and similar situations. As a side-question: the C2143 error is showing up in the first line of the first method declaration (i.e. the method's return type) in a .cpp file that includes only its associated .h file. Would anything other than semicolons or braces lead to this behaviour?

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