Re: [Boost-users] Using lambda bind as destruct functor to shared_ptr

From: Peter Dimov (pdimov_at_[hidden])
Date: 2007-07-04 12:40:51

Scott French wrote:
> Hello,
>
> Should the following code sample work? It is the simplest reproduction
> case I could come up with:
>
> #include <boost/lambda/lambda.hpp>
> #include <boost/lambda/bind.hpp>
> #include <boost/shared_ptr.hpp>
> #include <stdlib.h>
>
> using namespace std;
> using namespace boost;
> using namespace boost::lambda;
>
> int main(void)
> {
>     void * myResource = malloc(5);
>     shared_ptr<void> mySharedResource(myResource, bind(free, _1));
> }
>
> I get a compile error using g++ 4.0.1 on Mac OS X:

...

My personal opinion is that overloading unary & is evil. My professional 
opinion is that the code should work. :-) Please apply the following patch 
(already in CVS):

diff -u -r1.4 sp_counted_impl.hpp
--- boost/detail/sp_counted_impl.hpp    11 Nov 2005 21:06:08 -0000      1.4
+++ boost/detail/sp_counted_impl.hpp    4 Jul 2007 16:34:16 -0000
@@ -147,7 +147,7 @@

     virtual void * get_deleter( std::type_info const & ti )
     {
-        return ti == typeid(D)? &del: 0;
+        return ti == typeid(D)? &reinterpret_cast<char&>( del ): 0;
     }

 #if defined(BOOST_SP_USE_STD_ALLOCATOR)
@@ -217,7 +217,7 @@

     virtual void * get_deleter( std::type_info const & ti )
     {
-        return ti == typeid( D )? &d_: 0;
+        return ti == typeid( D )? &reinterpret_cast<char&>( d_ ): 0;
     }
 };