sample auto_ptr template

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3 total messages Started by Greg Colvin Sat, 30 Mar 1996 06:08

#3871

Author: Greg Colvin
Date: Sat, 30 Mar 1996 06:08

41 lines
2242 bytes

In Santa Cruz we decided to change the auto_ptr copy semantics to
allow returns of auto_ptr from functions.  Following is a simple
implementation.  It (almost) compiles with the latest Edison Design
Group front end (the template friend declaration choked it).  Note
that on most architectures the owner bit can be overlayed with the
pointer for a smaller footprint, but the following is portable.

template<class X>
   class auto_ptr {
      mutable bool owner;
      X* px;
      template<class Y> friend class auto_ptr;
   public:
      explicit auto_ptr(X* p=0) 
         : owner(p), px(p) {}
      template<class Y>
         auto_ptr(const auto_ptr<Y>& r) 
            : owner(r.owner), px(r.release()) {}
      template<class Y>
         auto_ptr& operator=(const auto_ptr<Y>& r) {
            if ((void*)&r != (void*)this) {
               if (owner) 
                  delete px;
               owner = r.owner; 
               px = r.release();
            }
            return *this;
         }
      ~auto_ptr()           { if (owner) delete px; }
      X& operator*()  const { return *px; }
      X* operator->() const { return px; }
      X* get()        const { return px; }
      X* release()    const { owner = 0; return px; }
   };

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Re: sample auto_ptr template

#3872

Author: Nathan Myers, http://www.cantrip...
Date: Fri, 29 Mar 1996 18:22

19 lines
1661 bytes

Greg Colvin wrote:
> In Santa Cruz we decided to change the auto_ptr copy semantics to
> allow returns of auto_ptr from functions.  Following is a simple
> implementation.  It (almost) compiles with the latest Edison Design
> Group front end (the template friend declaration choked it). 

I hasten to add, in defense of John Spicer's sterling reputation,
that this was not a released EDG front end, but John's pre-alpha
working copy (i.e., only as reliable as other peoples' released
versions :-).

Nathan Myers
ncm@cantrip.org
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Re: sample auto_ptr template

#3913

Author: Greg Colvin
Date: Thu, 04 Apr 1996 18:15

32 lines
2289 bytes

In article <315D79CD.4F28E83E@cantrip.org> "Nathan Myers, http://www.cantrip.org/" <ncm@cantrip.org> writes:
>Greg Colvin wrote:
>> In Santa Cruz we decided to change the auto_ptr copy semantics to
>> allow returns of auto_ptr from functions.  Following is a simple
>> implementation.  It (almost) compiles with the latest Edison Design
>> Group front end (the template friend declaration choked it). 
>
>I hasten to add, in defense of John Spicer's sterling reputation,
>that this was not a released EDG front end, but John's pre-alpha
>working copy (i.e., only as reliable as other peoples' released
>versions :-).

Yes, and I was most pleased to be able (at last) to compile auto_ptr.

Greg Colvin
gregor@netcom.com
>
>Nathan Myers
>ncm@cantrip.org
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