C++ Smart Pointer Question

[gioni_go]

Hello ,
I'm a little rusty on c++ so i want to ask a questions to the gurus.
I am trying to create a smart pointer(dont wanna use boost) and i want to know if the following implementation is ok :

#ifndef SMARTPTR_H_
#define SMARTPTR_H_

#ifdef __DEBUG__SESSION
#include <stdio.h>
#endif

namespace smartptr {

inline void DEBUG(const char *msg) {
#ifdef __DEBUG__SESSION
 printf("%s\n",msg);
#endif
}

template<typename T>
class SmartPtr {
 T *m_ptr;
 bool m_isCollection;
 int *m_refCount;
 int temp;

public:

 SmartPtr() :
  m_refCount(0), m_ptr(0), m_isCollection(0) {
  DEBUG("Default constructor.");
 }

 SmartPtr(T* ptr, bool isCollection = false) :
  m_refCount(0) {
  DEBUG("T* constructor.");
  reset(ptr, isCollection);
 }

 SmartPtr(const SmartPtr &other) :
  m_refCount(0) {
  reset(other.m_ptr, other.m_isCollection);
  other.release();
  DEBUG("Copy constructor.");
 }

 T* get() const {
  DEBUG("GET.");
  return m_ptr;
 }

 bool isValid() const {
  return (m_ptr != 0);
 }

 void reset(T* ptr, bool isCollection = false) {
  destroy();
  m_refCount = &temp;
  m_ptr = ptr;
  m_isCollection = isCollection;
  *m_refCount = 1;
  DEBUG("Reset.");
 }

 T* release() const {
  T* ptr = m_ptr;
  if (m_refCount) {
   (*m_refCount)++;
  }
  DEBUG("Released pointer ownership.");

  return ptr;
 }

 void destroy() {

  if (m_ptr && m_refCount) {
   (*m_refCount)--;
   if (*m_refCount == 0) {
    if (m_isCollection) {
     delete[] m_ptr;
     m_ptr = 0;
     DEBUG("Destroyed collection.");
     return;
    }

    delete m_ptr;
    m_ptr = 0;
    DEBUG("Destroyed single pointer.");
   }
  }

  if (m_refCount != 0) {
   m_refCount = 0;
  }
 }

 T* operator ->() const {
  return get();
 }

 T& operator *() const {
  return *get();
 }

 const SmartPtr& operator=(T* ptr) {
  reset(ptr);
  DEBUG("Op = T*.");
  return *this;
 }

 const SmartPtr& operator=(const SmartPtr<T> &other) {
  DEBUG("Equals");
  reset(other.m_ptr, other.m_isCollection);
  other.release();
  return *this;
 }

 ~SmartPtr() {
  destroy();
 }

};

}

#endif /* SMARTPTR_H_ */

I need to know especially the part where the reference counter is involved. I want to keep everything in the class on the stack so the m_refCount to a stack location. Is this illegal and if yes what are the dangers. Thx in advance.