Re: [boost] shared_ptr bug?

From: Darin Adler (darin_at_[hidden])
Date: 2001-10-18 02:42:02

on 10/18/01 12:24 AM, Darin Adler at darin_at_[hidden] wrote:

>       scoped_ptr<T> sp(p);
>       pn = new long(1); // may throw
>       --*old_pn; 
>       px = sp.release();

Oops. There's no such thing as scoped_ptr::release. Well, rather than open
that can of worms, another version:

   void reset(T* p=0) {
      if (px == p) return;  // fix: self-assignment safe
      if (*pn == 1) {
         T* old_px = px;
         px = p; 
         checked_array_delete(old_px);
      } 
      else { // allocate new reference counter
         long* old_pn = pn;
         try { pn = new long(1); }
         catch (...) {
           checked_delete(p);
           throw;
         } 
         --*old_pn;
         px = p;   
      } // allocate new reference counter
   } // reset

I think the scoped_ptr one is slightly more elegant, but I was dissuaded
from adding a scoped_ptr::release by the smart pointer documentation.

    -- Darin