[Boost-bugs] [Boost C++ Libraries] #5690: intrusive_ptr detach method

Subject: [Boost-bugs] [Boost C++ Libraries] #5690: intrusive_ptr detach method
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2011-07-12 15:22:40

#5690: intrusive_ptr detach method
------------------------------+---------------------------------------------
 Reporter:  nn-mail@…         |       Owner:  pdimov      
     Type:  Patches           |      Status:  new         
Milestone:  To Be Determined  |   Component:  smart_ptr   
  Version:  Boost 1.47.0      |    Severity:  Optimization
 Keywords:  intrusive_ptr     |  
------------------------------+---------------------------------------------
 It is very handy.
 In some cases like passing between threads or between functions.

 (e.g. Boost.ASIO needs this too)

 Instead of writing this code:
 {{{
 #!cpp

 intrusive_ptr<A> a(get_a());

 intrusive_add_ref(a.get());
 call(a.get());
 }}}

 One could write
 {{{
 #!cpp

 intrusive_ptr<A> a(get_a());

 call(a.detach());
 }}}

 The good thing in the second variation that we don't increase counter, so
 no 'lock' opcode to the processor. Better performance.

 Patch:
 {{{
 #!cpp
         void* detach()
         {
                 T * tmp = px;
                 px = 0;
                 return tmp;
         }
 }}}

 Thanx.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/5690>
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