Coding Tidbits and Style That Saved Me - Game Coding Complete - page 71

C++ s shared_ptr

If you think calling AddRef() and Release() all over the place might be a serious
pain in the rear, you

'

s really easy to forget an AddRef() or a Release()
call, and your memory leak will be almost impossible to find. It turns out that there
are plenty of C++ templates out there that implement reference counting in a way
that handles the counter manipulation automatically. One of the best examples is
the shared_ptr template class in the standard TR1 C++ library.
Here

' re right. It '

' s an example of how to use this template:

#include <memory>

using std::tr1::shared_ptr;

class IPrintable
{
public:
virtual void VPrint()=0;
};

class CPrintable : public IPrintable
{

char *m_Name;
public:
CPrintable(char *name) { m_Name = name; printf( “ create %s\n ” ,m_Name); }

virtual CPrintable() { printf( “ delete %s\n ” ,m_Name); }

˜

void VPrint() { printf( “ print %s\n ” ,m_Name); }

};

shared_ptr<CPrintable> CreateAnObject(char *name)
{

return shared_ptr<CPrintable>(new CPrintable(name));

}

void ProcessObject(shared_ptr<CPrintable> o)
{

printf(“(print from a function) ”);
o->VPrint();

}

void TestSharedPointers(void)
{

shared_ptr<CPrintable> ptr1(new CPrintable( “ 1 ” )); // create object 1

shared_ptr<CPrintable> ptr2(new CPrintable( “ 2 ” )); // create object 2