I want to recorded the line which created the shared_ptr in C++ 11. Here is my way to rewrite shared_ptr as Shared_ptr :
template<class T>
class Shared_Ptr{
public:
Shared_Ptr(T* ptr = nullptr,int line=__LINE__)
:_pPtr(ptr)
, _pRefCount(new int(1))
, _pMutex(new mutex)
{
cout<<this<<"is located in "<<line<<endl;
}
~Shared_Ptr()
{
Release();
cout<<this<<endl;
}
Shared_Ptr(const Shared_Ptr<T>& sp)
:_pPtr(sp._pPtr)
, _pRefCount(sp._pRefCount)
, _pMutex(sp._pMutex)
{
AddRefCount();
}
Shared_Ptr<T>& operator=(const Shared_Ptr<T>& sp)
{
//if (this != &sp)
if (_pPtr != sp._pPtr)
{
Release();
_pPtr = sp._pPtr;
_pRefCount = sp._pRefCount;
_pMutex = sp._pMutex;
AddRefCount();
}
return *this;
}
T& operator*(){
return *_pPtr;
}
T* operator->(){
return _pPtr;
}
int UseCount() { return *_pRefCount; }
T* Get() { return _pPtr; }
void AddRefCount()
{
_pMutex->lock();
++(*_pRefCount);
_pMutex->unlock();
}
private:
void Release()
{
bool deleteflag = false;
_pMutex->lock();
if (--(*_pRefCount) == 0)
{
delete _pRefCount;
delete _pPtr;
deleteflag = true;
}
_pMutex->unlock();
if (deleteflag == true)
delete _pMutex;
}
private:
int *_pRefCount;
T* _pPtr;
mutex* _pMutex;
};
class student
{
int age;
public:
student(int a):age(a)
{
}
}
;
int main()
{
Shared_ptr<student> Tom(new student(24),__LINE__);
}
Is there a way to make Shared_ptr<student>Tom(new student(24)) as same as Shared_ptr <student> Tom(new student(24),__ LINE__) in C++11? In other words , invoke class Constructor with the arguments bound to args.
I tried to use marco to achieve,but I don't know the correct way how to define the macro of template class constructor.
Below is the macro definition I tried to write but wrong
template<typename T>
#define Shared_ptr<T>::Shared_ptr(T*) Shared_ptr<T>::Shared_ptr(T * ,__LINE__)
Replace int line=__LINE__ in constructor parameters with int line = __builtin_LINE(). It's a non-standard compiler extension, but it works at least in GCC, Clang, and MSVC (i.e. most common compilers).
Then Shared_ptr<student> Tom(nullptr); will work.
Shared_ptr<student> Tom(42); will not work, because Shared_ptr doesn't have the right constructor, but it has nothing to do with getting the line number.
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