redefinition

I am trying to use a global variable from separated .cpp files. I have got an init.h file as: //init.h #ifndef init #define init int a = 3; #endif I have got an init.cpp file as: //init.cpp #include init.h Then finally my main.cpp file is: //main.cpp #include "init.h" int main(void) { while(1) { } } After this, I get the error: 1>init.obj : error LNK2005: "int a" (?a@@3HA) already defined in main.obj 1> ..deneme.exe : fatal error LNK1169: one or more multiply defined symbols found Why my #infdef control does not solve this problem?. I also tried using #pragma once but I got same error. What is

This question already has answers here : C++ Redefinition Header Files (winsock2.h) (16 answers) Closed 3 years ago . I am compiling a project in Visual C++ 2010, but I have problems with some Winsock redefinitions. First of all I get: syntax error : identifier 'SOCKADDR_STORAGE' But if I include winsock or winsock2 or ws2tcpip i get many errors like these: error C2011: 'sockaddr' : 'struct' type redefinition error C2011: 'WSAData' : 'struct' type redefinition error C2011: 'linger' : 'struct' type redefinition Your problem is that by including Windows.h , you are also already including winsock

What is the difference between <xs::redefine> and <xs::override> in XML schema 1.1. I've got two books on XML Schema in front of me and I still can't tell the difference. The only thing that I'm sure of is that both are pervasive and that <xs::redefine> is deprecated. Using redefine you can extend or restrict a component (complex types, simple types, model groups and attribute groups). So, you reuse the original definition of the component and you extend or restrict it. The override allows you to replace the definition of a component. So, you create a new component with the same name that

So, this is my trait: trait Cacheable { protected static $isCacheEnabled = false; protected static $cacheExpirationTime = null; public static function isCacheEnabled() { return static::$isCacheEnabled && Cache::isEnabled(); } public static function getCacheExpirationTime() { return static::$cacheExpirationTime; } } This is the base class: abstract class BaseClass extends SomeOtherBaseClass { use Cacheable; ... } These are my 2 final classes: class Class1 extends BaseClass { ... } class Class2 extends BaseClass { protected static $isCacheEnabled = true; protected static $cacheExpirationTime =

I'm using Visual Studio 2010. I'm trying to write simple Camera class in OpenGL. I need to include gl/gl.h in Camera.h gl/gl.h is already included in main.cpp and Camera.h is included in main.cpp When I put #include <gl/gl.h> in Camera.h i got bunch of errors like this one: Error 11 error C2086: 'int APIENTRY' : redefinition C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\gl\GL.h 1153 1 Gaz 3D files: Camera.h #include <math.h> #include <gl/gl.h> #ifndef _CAMERA_H #define _CAMERA_H class Camera { private: Camera(); public: static Camera& getCamera(); float x, y, z, rotv, roth; void

I am new to C++. Could anybody tell me the difference between method overriding and virtual function concepts in c++. The functionality of virtual functions can be over-ridden in its derived classes. Redefining a function in a derived class is called function overriding. why do we actually have virtual functions? pyon ABSTRACT In this paper, we discuss virtual functions in C++. Part zero explains how virtual functions are declared and overridden. Part one attempts (and perhaps fails) to explain how virtual functions are implemented. Part two is a sample program that uses the example classes

I'm new to C++, and I'm having a problem with my class definitions in a header file. The code for the header file (Student.h) is: #include <string> using namespace std; class Student { // Data Members for a Student string id; string preferences[3]; int skill; // Constructor public: Student(){} public: void SetID(string str) { this->id = str; } public: void SetSkill(int i) { this->skill = i; } public: void SetPreferences(int i, string s) { this->preferences[i] = s; } }; class StudentSchedule { public: StudentSchedule(){} }; The compiler error says that line 14 (class Student) is a redefinition

I'm running some Ruby code which evals a Ruby file every time its date changes. In the file, I have constant definitions, like Tau = 2 * Pi and, of course, they make the interpreter display the unwanted "already initialized constant" warning every time, so, I'd like to have the following functions: def_if_not_defined(:Tau, 2 * Pi) redef_without_warning(:Tau, 2 * Pi) I could avoid the warning by writing all my constant definitions like this: Tau = 2 * Pi unless defined?(Tau) but it is inelegant and a bit wet (not DRY ). Is there a better way to def_if_not_defined ? And how to redef_without