Confused, Why c++ global variable was not declared in this scope

Question

I am new to C++. I am trying to modify a very complex video codec code as part of my final year school project. I have already asked it on another thread but got no help. This is my code:

This is the header file in which I have declared three extern variables:

yuv.h

#include <vector>
namespace X265_NS 
{
extern int frameNumber;
extern int frameSize;
extern std::vector<int>numbers;

class YUVInput : public InputFile, public Thread
{
protected:

// some more variables

public:

// more variables and function declarations

};
}

This is the first file that uses these extern variables:

yuv.cpp

#include "yuv.h"
//more includes
#include <vector>

namespace X265_NS {
    int frameNumber;
    int frameSize;
    std::vector<int>numbers;
}

using namespace X265_NS;  

// some stuff and function calls
// here I use my extern variables in a function

frameNumber = readCount.get();
frameSize = ceil((double)height / 32) * ceil((double)width / 32);

//more stuff

bool YUVInput::populateFrameQueue()
{
   if(read<1)
             {
                  ifstream file("/home/abu-bakr/bin/test.txt");
                  int number;
                  while (file >> number)
                           numbers.push_back(number);
             }
}

// more stuff

This is the second class where I am using these extern variables:

analysis.cpp

#include "yuv.h"
#include <vector>
....
using namespace X265_NS;

// some stuff

// its in a function and only place where I am using these variables
int qp_ctu = numbers.at((ctu.m_cuAddr + 1) + (frameSize*(frameNumber - 1)));

// more stuff

This is the error I am getting that is making me really confused:

analysis.cpp
1>C:\x265_2.2\x265_2.2\source\encoder\analysis.cpp(170): warning C4244: '=' : conversion from 'int' to 'int8_t', possible loss of data
1>C:\x265_2.2\x265_2.2\source\encoder\analysis.cpp(2814): error C2065: 'numbers' : undeclared identifier
1>C:\x265_2.2\x265_2.2\source\encoder\analysis.cpp(2814): error C2228: left of '.at' must have class/struct/union
1>          type is ''unknown-type''
1>C:\x265_2.2\x265_2.2\source\encoder\analysis.cpp(2814): error C2065: 'frameSize' : undeclared identifier
1>C:\x265_2.2\x265_2.2\source\encoder\analysis.cpp(2814): error C2065: 'frameNumber' : undeclared identifier

yuv.cpp
2>C:\x265_2.2\x265_2.2\source\input\yuv.cpp(219): warning C4244: '=' : conversion from 'double' to 'int', possible loss of data
2>x265-static.lib(analysis.obj) : error LNK2005: "int x265::frameNumber" (?frameNumber@x265@@3HA) already defined in yuv.cpp.obj
2>x265-static.lib(analysis.obj) : error LNK2005: "int x265::frameSize" (?frameSize@x265@@3HA) already defined in yuv.cpp.obj
2>     Creating library C:/x265_2.2/x265_2.2/build/vc10-x86/Debug/x265.lib and object C:/x265_2.2/x265_2.2/build/vc10-x86/Debug/x265.exp
2>C:\x265_2.2\x265_2.2\build\vc10-x86\Debug\x265.exe : fatal error LNK1169: one or more multiply defined symbols found

Answer 1

You might be including a wrong file. Most likely there's another yuv.h file in some library source code which gets included in analysis.cpp instead of the one you need. You can quickly check this by adding some erroneous code into your yuv.h and trying to compile analysis.cpp.