Re: [Boost-bugs] [Boost C++ Libraries] #9668: insert_check and callees should pass KeyValueCompare by const reference

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #9668: insert_check and callees should pass KeyValueCompare by const reference
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2014-02-15 10:15:57

#9668: insert_check and callees should pass KeyValueCompare by const reference
-------------------------------+--------------------------
  Reporter:  vinnie.falco@…    |      Owner:  igaztanaga
      Type:  Bugs              |     Status:  closed
 Milestone:  To Be Determined  |  Component:  intrusive
   Version:  Boost 1.55.0      |   Severity:  Optimization
Resolution:  invalid           |   Keywords:
-------------------------------+--------------------------
Changes (by igaztanaga):

 * status:  new => closed
 * resolution:   => invalid

Comment:

 Thanks for the report. You can always wrap your function objects with a
 type that holds a reference to your heavyweight function object. Passing
 by const-reference forces operator() to be const which is not required
 right now (and thus, this is backwards incompatible). For other function
 objects used in Intrusive, like cloners and disposers, non-const
 operator() is very useful to recycle nodes.

 Usually function in the C++ standard algorithms predicates are passed as
 values for very good reasons:

 http://stackoverflow.com/questions/8196345/passing-functor-object-by-

 value-vs-by-reference-c

 I think you can always obtain the desired performance with a little
 wrapper. Passing by value is the intended behavior in Intrusive. Maybe not
 optimal in some cases, but this is by design.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/9668#comment:2>
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