id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
4538	Warning: dereferencing type-punned pointer will break strict-aliasing rules	Roland Bock <rbock@…>	No-Maintainer	"Hi,

compiling the attached example with gcc-4.4.3 (Ubuntu 10.4, 64bit) with

-Wall -O3

leads to a long warning message (second attachment), culminating in


{{{
boost/1.44/include/boost/function/function_base.hpp:321: warning: dereferencing type-punned pointer will break strict-aliasing rules
boost/1.44/include/boost/function/function_base.hpp:325: warning: dereferencing type-punned pointer will break strict-aliasing rules
}}}


A way to avoid this warning is been suggested by Justin in the boost-users mailing list:

http://lists.boost.org/boost-users/2010/08/61564.php

Replace:

{{{
reinterpret_cast<functor_type*>(&in_buffer.data)->~Functor();
}}}

with:

{{{
functor_type* p = reinterpret_cast<functor_type*>(&in_buffer.data);
p->~Functor();
}}}

(Second line with out_buffer, respectively)

As noted by Emil Dotchevski in the thread on boost-users, it seems questionable why splitting up the original lines can get rid of the warning. So maybe a ticket should be filed for gcc by someone more knowledgeable than me.
"	Bugs	closed	Boost 1.44.0	function	Boost 1.44.0	Problem	fixed