[Boost-users] The Memory leak occurs with intrusive_ptr<T> and a class which containing wstring member variable.

3 Dec 2007


      Hello everyone. I had met a memory leak error runnnin program generated
from a source which is attached to this mail.
[flow]
--The "sampleclass"-class has a wstring object as a member variable and
a setter and a getter for this variable.
--A sampleclass instance generated by the default new.
--A pointer to sampleclass instance attached to intrusive_ptr<sampleclass>.
--Make wstring instance with string L"0123456789abcdef".
--The wstring instance set to a sampleclass instance using the
sampleclass's setter.
--Finish this program and a memory leak occurs.
[emvironment]
WindowsXP 64bit
VisualStudio2005 sp1
boost-1_34_1
Unicode Charset


#include "stdafx.h"

#include <iostream>
#include <boost/intrusive_ptr.hpp>
#include <boost/detail/atomic_count.hpp>
#include <boost/config.hpp> 
using namespace std;
using namespace boost;

#ifdef _DEBUG
#define _CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <crtdbg.h>
#define new ::new(_NORMAL_BLOCK, __FILE__, __LINE__)
#endif

namespace test {
	class countable {
	public:
		countable() : refcount(0) { }
		void add_ref( void ) { ++refcount; }
		void release( void ) { 
			if( 0 == --refcount ) {
				delete this;			
			}
		}
		int getcount() { return static_cast<long>(refcount); }
	private:
		boost::detail::atomic_count refcount;
	};
	class sampleclass : public countable {
		wstring message;
	public:
		sampleclass(){}
		sampleclass( const wstring &mes ) : message(mes) {}
		void setmessage( const wstring &mes ) {
			message = mes;
		}
		wstring getmessage() { return message; }
	};
};

namespace boost {
	using namespace test;
	inline void intrusive_ptr_add_ref(countable *p) {
		p->add_ref();
	}
	inline void intrusive_ptr_release(countable *p) {
		p->release();
	}
}

int _tmain(int argc, _TCHAR* argv[])
{
	_CrtSetDbgFlag(_CRTDBG_ALLOC_MEM_DF|_CRTDBG_LEAK_CHECK_DF);
	using namespace test; {
		intrusive_ptr<sampleclass> intrusive_( new sampleclass(wstring(L"initial")) );
		//---------- memory leak prone ------------------------//
		wstring mes( L"0123456789abcdef" );
		intrusive_->setmessage( mes );
		//---------- memory leak prone ------------------------//
		wcout << intrusive_->getmessage().c_str() << endl;
	}
	getchar();
	return EXIT_SUCCESS;
}

[Boost-users] The Memory leak occurs with intrusive_ptr<T> and a class which containing wstring member variable.

Youhei Murakami