multiple definition in stl class header

Question

I am getting stuck using this class, when I used in the main.cpp there is no problem and execute perfectly, but when I use it as a member class the compiler doesn't like it and sends the message "Multiple definition of:" Here is the class:

RTPSocket.h:

#ifndef RTP_SOCKET_HDR
#define RTP_SOCKET_HDR
    namespace RTPConnection
    {

    enum EMode
    {
        Sender,
        Receiver
    };

    template<EMode Mode>
    class RTPSocket
    {
    };
    }//end namespace


#define RTP_SOCKET_IMP
#include "RTPSocket_Imp.h"//file where i declare the implementation code
#undef RTP_SOCKET_IMP
#endif

this class by itself doesn't have any problem but when i use it in my class, but .... used in another class my file.h

#include RTPSocket.h 
class CommClass
{
private:
RTPSocket<RTPConnection::Receiver>  * mRTPServer;
}

the compiler give this error message: multiple definition of 'enum RTPConnection::EMode'

this is a method that is declared in another file "rtpsocket_imp.h" with the guard declared:

template<EMode Mode>
void RTPSocket<Mode>::write(char* aArray, 
                                      const size_t aiSize)
{
    std::string message("The write function is operative only on Sender Mode");
    throw BadTemplate(message);
}

template void RTPSocket::write(char* aArray, const size_t aiSize) { std::string message("The write function is operative only on Sender Mode"); throw BadTemplate(message); } this method was writting was declared in rtpsocke_imp.h and the guard have been included — Ricardo_arg, Jul 15 '13 at 15:56

Mike Seymour · Answer 1 · 2013-07-15T15:59:54.737

4

You want include guards around the header:

#ifndef RTPSOCKET_H
#define RTPSOCKET_H

// header contents go here

#endif

This will prevent the header contents from being included more than once per source file, so you will not accidentally get multiple definitions.

UPDATE: Since you say you have include guards, then possible causes of the error might be:

misspelling the include guard name, so it doesn't work
defining something with the same name in another header (or the source file that includes it)
undefining the include guard name.

But without seeing code that reproduces the error, I can only guess what might be wrong.

edited Jul 15 '13 at 15:59

answered Jul 15 '13 at 15:13

Mike Seymour

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sorry i didnt mentiod in the original post, but the guard are included – Ricardo_arg Jul 15 '13 at 15:43
@Ricardo_arg: Then please post some code (including the guards) that actually reproduces the error; we can only guess what's wrong with the code you don't show us. – Mike Seymour Jul 15 '13 at 15:56

score 3 · Answer 2 · edited May 23 '17 at 12:31

3

You need an include guard. Inside the RTPSocket.h file at the top put

#ifndef RTPSOCKET_INCLUDED
#define RTPSOCKET_INCLUDED

and at the end put

#endif

If that's not the problem, and you do have an include guard, I suggest you search for

enum EMode

in your code and find all the places you have defined it, and make sure you just define it once.

edited May 23 '17 at 12:31

Community

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answered Jul 15 '13 at 15:13

doctorlove

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Guard are included, sorry i didnt put in the original post – Ricardo_arg Jul 15 '13 at 15:33

score 0 · Answer 3 · answered Jul 19 '13 at 21:06

0

My problem was the CMakeLists.txt that was building this project. My fault!

answered Jul 19 '13 at 21:06

Ricardo_arg

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multiple definition in stl class header

3 Answers3