Search Results

Search found 6460 results on 259 pages for 'cpp person'.

Page 148/259 | < Previous Page | 144 145 146 147 148 149 150 151 152 153 154 155  | Next Page >

• How to call C++ function from C?

  - by claws

  I know this. Calling C function from C++: If my application was in C++ and I had to call functions from a library written in C. Then I would have used //main.cpp extern "C" void C_library_function(int x, int y);//prototype C_library_function(2,4);// directly using it. This wouldn't mangle the name C_library_function and linker would find the same name in its input *.lib files and problem is solved. Calling C++ function from C??? But here I'm extending a large application which is written in C and I need to use a library which is written in C++. Name mangling of C++ is causing trouble here. Linker is complaining about the unresolved symbols. Well I cannot use C++ compiler over my C project because thats breaking lot of other stuff. What is the way out? By the way I'm using MSVC

  Read the article

• How should I get Xcode to link an iOS project that uses a C++ static library

  - by user1681572

  Using Xcode, I've written a Cocoa Touch static library, mainly in C++. It exposes a C interface for the benefit of Objective-C client code. I have a client iOS app that uses it, and everything works and runs as expected, except that I found I needed to include a minimal .cpp file in the client project to get the link to succeed. Otherwise I get C++-related unresolved symbols, e.g. operator new(unsigned long). The above hack is easy and effective, and so I guess I'm not breaking any laws, but is there a proper way to eliminate my linker errors?

  Read the article

• aligning extern constants (gcc)

  - by ~buratinas

  I want to make some static constants globally visible. I'm pretty familiar how to do that in C++. The problem is that these constants need to be aligned to some exotic boundary. Do I have to specify the alignment in extern declaration? I'm using GCC4.5 in *.cpp file static const constant_t constant __attribute__((aligned(64))) = {blah,blah,blah}; in *.h file //Which one is correct? extern const constant_t constant; extern const constant_t constant __attribute__((aligned(64)));

  Read the article

• Call a non member funcion on an instance before is constructed.

  - by Tom

  Hi everyone. I'm writing a class, and this doubt came up. Is this undef. behaviour? On the other hand, I'm not sure its recommended, or if its a good practice. Is it one if I ensure no exceptions to be thrown in the init function? //c.h class C{ float vx,vy; friend void init(C& c); public: C(); ~C(); }; //c.cpp C::C() { init(*this); } void init(C& c) //throws() to ensure no exceptions ? { c.vx = 0; c.vy = 0; } Thanks in advance

  Read the article

• Compiling without setting up a project in NetBeans or Visual Studio

  - by aLostMonkey

  Hi, In short: is there a way to compile and run single file in NetBeans or Visual Studio without having to setup and tinker with projects? I'm currently using code::blocks as my IDE. It's fast and very simple: perfect for my needs as a begginner. I wanted to dive a little deeper and try out a more advanced IDE such as NetBeans or Visual Studio. It appears I have to mess with projects and have a setup that seems overkill for having to compile and run one very simple .c/.cpp source file that contains less than 50-100 lines of code etc. Is there a way around this?

  Read the article

• Compilation failing - no #include - boost

  - by jwoolard

  Hi, I'm trying to compile a third-party library, but g++ is complaining about the following line: typedef boost::shared_ptr<MessageConsumer> MessageConsumerPtr; The strange thing is, there is no #include directive in the file - and it is clearly supposed to be this way; there are about 60 files with the same (or very similar) issues. Clearly if there was an #include directive referencing the relevant boost header this would compile cleanly. My question is: how can I get g++ to somehow automagically find the relevant symbol (in all instances of this issue, it is a namespace that can't be found - usually std:: or boost::) by either automatically processing the relevant header (or some other mechanism). Thanks. Edit My current g++ call looks like: g++ -fPIC -O3 -DUSING_PCH -D_REENTRANT -I/usr/include/boost -I./ -c MessageInterpreter.cpp -o MessageInterpreter.o

  Read the article

• Call a non member function on an instance before is constructed.

  - by Tom

  Hi everyone. I'm writing a class, and this doubt came up. Is this undef. behaviour? On the other hand, I'm not sure its recommended, or if its a good practice. Is it one if I ensure no exceptions to be thrown in the init function? //c.h class C{ float vx,vy; friend void init(C& c); public: C(); }; //c.cpp C::C() { init(*this); } void init(C& c) //throws() to ensure no exceptions ? { c.vx = 0; c.vy = 0; } Thanks in advance

  Read the article

• Calling C++ function from C.

  - by claws

  I know this. Calling C function from C++: If my application was in C++ and I had to call functions from a library written in C. Then I would have used //main.cpp extern "C" void C_library_function(int x, int y);//prototype C_library_function(2,4);// directly using it. This wouldn't mangle the name C_library_function and linker would find the same name in its input *.lib files and problem is solved. Calling C++ function from C??? But here I'm extending a large application which is written in C and I need to use a library which is written in C++. Name mangling of C++ is causing trouble here. Well I cannot use C++ compiler over my C project because thats breaking lot of other stuff. What is the way out? By the way I'm using MSVC

  Read the article

• c++ compilation error

  - by clamp

  hello, i got a compile error which i do not understand. i have a h/cpp file combination that does not contain a class but just defines some utility functions. when i try to use a struct that is defined in another class i get the error: error C2027: use of undefined type so, stripped down to the problem, the h file looks like this namespace A { void foo(B::C::SStruct const & Var); } the definition of SStruct is in a class which is in another h-file, that is of course included. namespace B { Class C { struct SStruct { }; } } what am i missing here? thanks!

  Read the article

• g++: how to specify preference of library path?

  - by Heinrich Schmetterling

  I'm compiling a c++ program using g++ and ld. I have a .so library I want to be used during linking. However, a library of the same name exists in /usr/local/lib, and ld is choosing that library over the one I'm directly specifying. How can I fix this? For the examples below, my library file is /my/dir/libfoo.so.0. Things I've tried that don't work: my g++ command is "g++ -g -Wall -o my_binary -L/my/dir -lfoo bar.cpp" adding /my/dir to the beginning or end of my $PATH env variable adding /my/dir/libfoo.so.0 as an argument to g++ Thanks.

  Read the article

• C++ Static Array Initialization - Memory Issue

  - by donalmg

  Hi, I have a header file which contains a member variable declaration of a static char array: class ABC { public: static char newArray[4]; // other variables / functions private: void setArray(int i, char * ptr); } In the CPP file, I have the array initialized to NULL: char ABC::newArray[4] = {0}; In the ABC constructor, I need to overwrite this value with a value constructed at runtime, such as the encoding of an integer: ABC::ABC() { int i; //some int value defined at runtime memset(newArray, 0, 4); // not sure if this is necessary setArray(i,newArray); } ... void setArray(int i, char * value) { // encoding i to set value[0] ... value [3] } When I return from this function, and print the modified newArray value, it prints out many more characters than the 4 specified in the array declaration. Any ideas why this is the case. I just want to set the char array to 4 characters and nothing further. Thanks...

  Read the article

• How to use a variable inside a _T wrapper?

  - by karikari

  I want to make the hostname part of this string to be variable.. Currently, it is only fix to this URL: _T(" --url=http://www.myurl.com/ --out=c:\\current.png"); I want to make something like this, so the URL is changeable.. _T(" --url=http://www." + myurl + "/ --out=c:\\current.png"); update. Below is my latest attempt: CString one = _T(" --url=http://www."); CString two(url->bstrVal); CString three = _T("/ --out=c:\\current.png"); CString full = one + two + three; ShellExecute(0, _T("open"), // Operation to perform _T("c:\\IECapt"), // Application name _T(full),// Additional parameters 0, // Default directory SW_HIDE); The error is : Error 1 error C2065: 'Lfull' : undeclared identifier c:\test.cpp

  Read the article

• Two phase Construction in C++

  - by tommieb75

  I have as part of assignment to look into a development kit that uses the "two-phase" construction for C++ classes: // Include Header class someFubar{ public: someFubar(); bool Construction(void); ~someFubar(); private: fooObject _fooObj; } In the source // someFubar.cpp someFubar::someFubar : _fooObj(null){ } bool someFubar::Construction(void){ bool rv = false; this->_fooObj = new fooObject(); if (this->_fooObj != null) rv = true; return rv; } someFubar::~someFubar(){ if (this->_fooObj != null) delete this->_fooObj; } Why would this "two-phase" be used and what benefits are there? Why not just instantiate the object initialization within the actual constructor?

  Read the article

• Hoard allocator not "working"?

  - by Cowboy

  I'm trying to Hoard allocator to work, but it seems it doesn't. I have a benchmark application that does a lot of dynamic memory management. The execution time for Hoard and glibc memory manager is the same. It makes me wonder if I'm doing the right thing. What I do is... export LD_PRELOAD="/path/libhoard.so" g++ main.cpp -O3 -o bm -lpthread -lrt Shouldn't I have to link to Hoard allocator? Does it matter what path (in LD_PRELOAD) is, or can I have whatever path? I'm running Ubuntu 8.04, and g++ 4.2.4 Cheers

  Read the article

• C++ Vector of vectors

  - by xbonez

  I have a class header file called Grid.h that contains the following 2 private data object: vector<int> column; vector<vector<int>> row; And a public method whose prototype in Grid.h is such: int getElement (unsigned int& col, unsigned int& row); The definition of above mentioned function is defined as such in Grid.cpp: int getElement (unsigned int& col, unsigned int& row) { return row[row][col] ; } When I run the program, I get this error: error C2109: subscript requires array or pointer type Whats going wrong?

  Read the article

• QConnect find no such slot on QCombobox by Qt Creater

  - by user2534154

  I create a window inherit from QWidget I set grid layout to that Window I make a function called handleHeroChange(int index) in public slot inside that window I add a Qcombobox to call that function handleHeroChange(int index). Qtcreator keep telling: QObject::connect: No such slot QWidget::handleHeroChange(int) in ../Testing/Window.cpp:92 Why did i do wrong? THE CODE: Window::Window(QWidget *parent) : QWidget(parent) { QGridLayout *grid = new QGridLayout(this); QComboBox *comboHeroClass = new QComboBox(); comboHeroClass->addItem("Witcher"); comboHeroClass->addItem("Maurander"); comboHeroClass->setCurrentIndex(1); grid->addWidget(comboHeroClass, 2,3,1,1); QComboBox::connect(comboHeroClass, SIGNAL(currentIndexChanged(int)),this, SLOT(handleHeroChange(int))); } void Window::handleHeroChange(int index){ QPixmap myImage; if(index == 0){ }else if(index == 1){ } }

  Read the article

• a macro question for c language (#define)

  - by Daniel

  I am reading source code of hoard memory allocator, and in the file of gnuwrapper.cpp, there are the following code #define CUSTOM_MALLOC(x) CUSTOM_PREFIX(malloc)(x) What's the meaning of CUSTOM_PREFIX(malloc)(x)? is CUSTOM_PREFIX a function? But as a function it didn't defined anywhere. If it's variable, then how can we use variable like var(malloc)(x)? more code: #ifndef __GNUC__ #error "This file requires the GNU compiler." #endif #include <string.h> #include <stdlib.h> #include <stdio.h> #include <malloc.h> #ifndef CUSTOM_PREFIX ==> here looks like it's a variable, so if it doesn't define, then define here. #define CUSTOM_PREFIX #endif #define CUSTOM_MALLOC(x) CUSTOM_PREFIX(malloc)(x) ===> what's the meaning of this? #define CUSTOM_FREE(x) CUSTOM_PREFIX(free)(x) #define CUSTOM_REALLOC(x,y) CUSTOM_PREFIX(realloc)(x,y) #define CUSTOM_MEMALIGN(x,y) CUSTOM_PREFIX(memalign)(x,y)

  Read the article

• Problem with Initializing Consts

  - by UdiM

  This code, when compiled in xlC 8.0 (on AIX 6.1), produces the wrong result. It should print 12345, but instead prints 804399880. Removing the const in front of result makes the code work correctly. Where is the bug? #include <stdio.h> #include <stdlib.h> #include <string> long int foo(std::string input) { return strtol(input.c_str(), NULL, 0); } void bar() { const long int result = foo("12345"); printf("%u\n", result); } int main() { bar(); return 0; } Compilation command: /usr/vacpp/bin/xlC example.cpp -g

  Read the article

• Are unspecified and undefined behavior required to be consistent between compiles?

  - by sharptooth

  Let's pretend my program contains a specific construct the C++ Standard states to be unspecified behavior. This basically means the implementation has to do something reasonable but is allowed not to document it. But is the implementation required to produce the same behavior every time it compiles a specific construct with unspecified behavior or is it allowed to produce different behavior in different compiles? What about undefined behavior? Let's pretend my program contains a construct that is UB according to the Standard. The implementation is allowed to exhibit any behavior. But can this behavior differ between compiles of the same program on the same compiler with same settings in the same environment? In other words, if I dereference a null pointer on line 78 in file X.cpp and the implementation formats the drive in such case does it mean that it will do the same after the program is recompiled?

  Read the article

• Class templating std::set key types

  - by TomFLuff

  I have a class to evaluate set algebra but wish to template it. At the minute it looks a bit like this set.h: template<typename T> class SetEvaluation { public: SetEvaluation<T>(); std::set<T> evaluate(std::string in_expression); } set.cpp template<typename T> std::set<T> SetEvaluation<T>::evaluate(std::string expression) { std::set<T> result; etc etc... } But i'm getting undefined reference errors when compiling. Is it possible to declare the return type as std::set<T> and then pass std::string as the class template param. There are no errors in the class but only when I try to instantiate SetEvaluation<std::string> Can anyone shed light on this problem? thanks

  Read the article

• NetBeans/C++ - how to choose the "main file" other than when creating a project?

  - by Petike

  Hello, when I am creating a C++ project in NetBeans, there is a toggle button "Create main file" - I just enter a name for it and that's all. The problem is that I cannot put that file in a "different" folder than right in the main project folder. And I am "used" to put all the source files in a "src" folder (and its subfolders), but at the "project creation time" I "cannot" put the main file there. So I tried "not" to create the main file at project creation, but after that create manually the "src" file and then create a "cpp" file in that folder (this is "allowed" in NetBeans). But NetBeans could not find "which" is the main file. So how can I choose the main file other than when creating a project (if it is possible)?

  Read the article

• Removing Unused (Unreferenced) Static Global Variable Constants in C++

  - by Synetech inc.

  Hi, I have a header file with a few common constants like names and stuff that are automatically included in each project (an example follows). The thing is that they are included in the compiled binary (EXE) whether they are used (referenced) or not. If I use DEFINEs instead, then naturally they are not included if they are not used, but of course consts are better than defines so… I tried Googling it, but the closest thing I could find was a question right here on SO that did not quite help. Matters of i18n aside, how can I keep the ones that are not used out of the binary, while still keeping it easy to use like this? Thanks. //COMMON.H: static const CString s_Company _T("Acme inc."); //etc. static const CString s_Digits _T("0123456789"); //TEST.CPP: #include common.h int main() { AfxMessageBox(s_Company); } //s_Company should be in the final EXE, but s_Digits should not be, but is

  Read the article

• Can I expand macro JUST ONE TIME in specific target?

  - by naive231

  A = "demo" %.o:%.cpp $(CC) -c $^ $(A) -o $@ default:$(all_objs) game:A = $(shell read -p 'Enter game version: ' gv && echo $$gv) game:$(all_objs) Just a snippet makefile above. If I make game, main problem is each compilation of sources will expand $(A) and it will request user to input game version over and over. $(A) has default content "demo" only if user doesn't make game target. So, is there any way to set $(A) to be expanded && ?

  Read the article

• The pImpl idiom and Testability

  - by Rimo

  The pImpl idiom in c++ aims to hide the implementation details (=private members) of a class from the users of that class. However it also hides some of the dependencies of that class which is usually regarded bad from a testing point of view. For example if class A hides its implementation details in Class AImpl which is only accessible from A.cpp and AImpl depends on a lot of other classes, it becomes very difficult to unit test class A since the testing framework has no access to the methods of AImpl and also no way to inject dependency into AImpl. This has been a problem for me lately and I am beginning to think that the pImpl idiom and writing testable code don't mix well. Has anyone come across this problem before? and have you found a solution?

  Read the article

• How to create and add a custom made component to a Dialog based app (MFC)?

  - by kobac

  I want to make a custom made component (a line chart), that would be used in other applications. I don't know 2 things: 1) Where should I use (within component class!) the methods for drawing, like FillRect or PolyLine? In OnPaint handler that I should define and map it in MESSAGE MAP? Will it (OnPaint handler) be called from OnPaint handler of the dialog of the application or where from? 2)How to connect the component, once it is made, to the test application, which will for example be dialog based? Where should I instantiate that component? From an OnCreate method of the MyAppDialog.cpp? I started coding in MFC few days ago and I'm so confused about it. Thanks in advance, Cheers.

  Read the article

< Previous Page | 144 145 146 147 148 149 150 151 152 153 154 155  | Next Page >