Redefinition Error
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Error Redefinition Of C++
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Stack Overflow Community Stack Overflow is a community of 6.2 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up GCC compiler error: “redefinition…previously defined” redefinition of class c++ inheritance up vote 7 down vote favorite 3 I'm getting a lot of " redefinition of x....x previously defined here". Please what does this error means? c++ gcc compiler-construction share|improve this question asked Apr 2 '09 at 1:00 caesar add a comment| 3 Answers 3 active oldest votes up vote 20 down vote You need to limit each file from being included only once. You can do c++ redefinition of variable this in 2 ways. 1) At the top of your header files put: #pragma once Or 2) if your compiler doesn't support that, put at the top/end of your header files: #ifndef _MYFILE_H_ #define _MYFILE_H_ ... #endif Replace MYFILE with the name of your file, and replace ... with the contents of the header file. share|improve this answer edited Apr 2 '09 at 7:11 unwind 256k39332460 answered Apr 2 '09 at 1:18 Brian R. Bondy 199k82475574 1 I think that #pragma only works in VC++, not in gcc. The #define trick is portable. –Gorpik Apr 2 '09 at 7:19 supoprted by gcc and vc++ –Brian R. Bondy Apr 2 '09 at 10:29 Wikipedia says #pragma once is supported by VC++ and gcc en.wikipedia.org/wiki/Pragma_once . –Max Lybbert Apr 3 '09 at 20:48 #pragma works fine with gcc.. I'm using it at this very moment after I reading about it and it solved a ton of errors! –mmoment Sep 7 '12 at 14:13 add a comment| up vote 9 down vote The error means that there is a symbol that has been defined in one place and an alternate definition has
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Previous Definition Of Class C++
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is a community of 6.2 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up Why am I getting this redefinition of class error? up vote 6 http://stackoverflow.com/questions/707920/gcc-compiler-error-redefinition-previously-defined down vote favorite 1 Apologies for the code dump: gameObject.cpp: #include "gameObject.h" class gameObject { private: int x; int y; public: gameObject() { x = 0; y = 0; } gameObject(int inx, int iny) { x = inx; y = iny; } ~gameObject() { // } int add() { return x+y; } }; gameObject.h: class gameObject { private: int x; int y; public: gameObject(); gameObject(int inx, int iny); ~gameObject(); http://stackoverflow.com/questions/3746484/why-am-i-getting-this-redefinition-of-class-error int add(); }; Errors: ||=== terrac, Debug ===| C:\terrac\gameObject.cpp|4|error: redefinition of `class gameObject'| C:\terrac\gameObject.h|3|error: previous definition of `class gameObject'| ||=== Build finished: 2 errors, 0 warnings ===| I can't figure out what's wrong. Help? c++ class redefinition share|improve this question edited Mar 14 '14 at 8:09 sellibitze 18.1k24076 asked Sep 19 '10 at 16:26 Dataflashsabot 4362922 add a comment| 7 Answers 7 active oldest votes up vote 22 down vote accepted You're defining the class in the header file, include the header file into a *.cpp file and define the class a second time because the first definition is dragged into the translation unit by the header file. But only one gameObject class definition is allowed per translation unit. You actually don't need to define the class a second time just to implement the functions. Implement the functions like this: #include "gameObject.h" gameObject::gameObject(int inx, int iny) { x = inx; y = iny; } int gameObject::add() { return x+y; } etc share|improve this answer answered Sep 19 '10 at 16:29 sellibitze 18.1k24076 1 Ahhhh, thank you! –Dataflashsabot Sep 19 '10 at 16:34 add a comment| Did you find this question interesting? Try our newsletter Sign up for our newsletter and get our top new questions
}; Integer.cpp 1 a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn more about hiring developers or posting ads with us Arduino beta Questions Tags Users Badges Unanswered Ask Question _ Arduino Stack Exchange is a question and answer site for developers of open-source hardware and software that is compatible with Arduino. Join them; it only takes a minute: Sign up Here's how it works: Anybody can ask a question Anybody can answer The best answers are voted up and rise to the top error: redefinition of ' ' up vote 2 down vote favorite 1 When I am trying to compile the following code, int delayTime = 1; int charBreak = 2.1; #include
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#include "Object.cpp" class Integer : public Object { }; Boolean.cpp 1
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#include "Object.cpp" class http://www.cplusplus.com/forum/beginner/4915/ Boolean : public Object { }; Main.cpp 1
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#include "Integer.cpp" #include "Object.cpp" int main() { Integer i; Boolean b; return 0; } When i compile the http://arduino.stackexchange.com/questions/3331/error-redefinition-of project i get error as error C2011: 'Object' : 'class' type redefinition Now, in Main.cpp file i make use of both Integer and Boolean so isn't definition of including this files valid? help appreciated amal Oct 17, 2008 at 8:42am UTC guestgulkan (2942) Yes you will get C2011: 'Object' : 'class' type redefinition error. This is because main.cpp line 1 - includes interger.cpp which itself includes object.cpp. and on line 2 there is include object.cpp So object cpp gets included of class c++ twice which means that class Object is seen twice by the compiler - hence the error. The way you are including cpp files is not the recommended way of doing things. Class declarations are usually put into header files. The code for the class is put into the cpp file. The header file should have a header guard to prevent multiple inclusion errors. Example of header guard object.h 1
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//header guard at start of header file #ifndef OBJECT_H #define OBJECT_H class Object { }; //End guard at bottom of header file #endif Do something similar for the other class declaration files; integer.h 1
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#ifndef INTEGER_H #define INTEGER_H #include "Object.h" class Integer : public Object { }; #endif boolean.h 1
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#ifndef BOOLEAN_H #define BOOLEAN_H #include "Object.h" class Boolean : public Object { }; #endif Then in main.cpp you will have: 1
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#include "Integer.h" #include "Object.h" //probably won't need this line #include boolean.h