Question about One Definition Rule

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One Definition Rule Violation

So, definition is more general term than implementation and in case of C programming language definition is reduced to implementation, correct?

@Akashay K
Thanks for ODR violation,  could you please provide something that I can test to violate in gcc compiler?

>>So, definition is more general term than implementation and in case of C programming language definition is reduced to
>>implementation, correct?

Indeed. I'd usually also go by the term 'implementation', but 'definition' here means the same and also covers instances and variables.

I have got it, if we say

int i = 6; //integer i implements number 6

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, it sounds a bit weird :)

Defining instances of class?

//tu1.cpp

struct X {
    X(int);
    X(int, int);
};
X::X(int = 0) { }
class D: public X {};
D d2;


int main(){}

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//tu2.cpp

struct X {
    X(int);
    X(int, int);
};
X::X(int = 0, int = 0) {}
class D: public X { };

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g++ tu1.cpp tu2.cpp
compiles like a charm.

jkr, Could you modify this links in order to make them cross reference? Still don't get this.

The problem about doing so is that it would defy the very purpose of your example. E.g.

// X.h
struct X {
    X(int);
    X(int, int);

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// tu1.cpp
#include "X.h"
X::X(int = 0) { }
class D: public X {};
D d2;

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#include "X.h"
X::X(int = 0) {int i = i;}
class D: public X { };

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which correctly yields

$ g++ tu1.cpp tu2.cpp
/tmp/cc9v8yr7.o:tu2.cpp:(.text+0x0): multiple definition of `X::X(int)'
/tmp/ccsPYguC.o:tu1.cpp:(.text+0x0): first defined here
/tmp/cc9v8yr7.o:tu2.cpp:(.text+0x0): multiple definition of `X::X(int)'
/tmp/ccsPYguC.o:tu1.cpp:(.text+0x0): first defined here

Some minor bugs have been fixed in expert's answer.