Re: will it cause memory leak?

From:
cbarron3@ix.netcom.com (Carl Barron)
Newsgroups:
comp.lang.c++.moderated
Date:
3 Jul 2006 07:10:35 -0400
Message-ID:
<1hhv53g.hovhko1gzu6vpN%cbarron3@ix.netcom.com>
Rayer <shivanna@gmail.com> wrote:

consider the code below :

if(char* thechar = new char[(strlen(pylon)+1)])
{
....//do something
}
else
{
...//do something if fail to deploy memory
}

actually, "thechar" have been given a memory space in a if-scope, will
it destroy(delete) itself as soon as process goes out of the scope? or
it still need a delete to avoid memory leak?

tks all, regards.


    My advice is don't use new/delete operators directly in any high
level code if possible not to do so. A common idiom is RAII
  Resource Allocation Is Initialization, allocate in a ctor and
deallocate in a dtor of a non copyable class.

   template <clsss T>
   class buffer_ptr
   {
      typedef typename boost::shared_ptr<T> smart_type;
      smart_type ptr;
      struct array_deleter
      {
         template <class U>
         void operator () (U* u) {delete [] u;}
      };
   public:
      explicit buffer_ptr(std::size_t n)
        :ptr(new T[n],array_deleter()){}

      T* get() const {return ptr.get();}
      operator bool() {return ptr.operator bool();}
   };
  // ...

   if(buffer_ptr<char> buffer(std::strlen(pylon)))
   {
       char * ptr = buffer.get();
       // don't delete ptr
       // use ptr
   }
   else
   {
      // failure code,
   }

it is possible to write a buffer_ptr as a non copyable stack class
which just holds array news a pointer on constrution and array deletes
in the dtor. with the member functions get() and operator bool().

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