inline constructors

[aryan]

Hello,

The following code throws "undefined reference to `Buster::Buster()'"
unless I remove inline keyword. Could someone please explain why?

//************************
// In file buster.h
//************************
class Buster {
private:
static int instanceCount;
public:

Buster();

virtual
~Buster();

static
int
getInstanceCount();

};

//**************************
//In file buster.cpp
//**************************
int
Buster::instanceCount = 0;

inline
Buster::Buster() {
instanceCount++;
}

int
Buster::getInstanceCount() {
return instanceCount;
}

inline
Buster::~Buster() {
instanceCount--;
}
///////////////////////////////////////

Thanks.

 

[Jonathan Lee]

Hello,

The following code throws "undefined reference to `Buster::Buster()'"
unless I remove inline keyword. Could someone please explain why?

Inline functions must be defined in every translation unit
in which they're used.

see, for example: http://stackoverflow.com/questions/908830/isnt-cs-inline-totally-optional

or http://en.wikipedia.org/wiki/One_Definition_Rule noting item 3 in
the summary about extern inline functions

--Jonathan

 

[aryan]

So moving the inline definitions to the header file should solve the
problem, right?

Its strange the inline definition of destructor in .cpp file did not
cause any error. I guess this is because the destructor cannot be
called explicitly.

 

[Jonathan Lee]

So moving the inline definitions to the header file should solve the
problem, right?

Or dropping the inline keyword.

Its strange the inline definition of destructor in .cpp file did not
cause any error. I guess this is because the destructor cannot be
called explicitly.

My guess would be that since the constructor couldn't be
found (and thus the type couldn't be instantiated),
it never even looked for the destructor.

--Jonathan

 

[aryan]

My guess would be that since the constructor couldn't be
found (and thus the type couldn't be instantiated),
it never even looked for the destructor.

I only corrected the constructor. It compiles without warnings/errors.

-
Kiran