On 2010-01-05 20:50:38 +0000, Andrew Haley wrote: > On 01/05/2010 07:58 PM, Joshua Haberman wrote: > > Andrew Haley <aph <at> redhat.com> writes: > >> but > >> > >> (union u*)&i > >> > >> is not a legal lvalue expression because the dereference is undefined > >> behaviour. > > > > Your example does not contain a dereference. > > > >> You may only dereference a pointer as permitted by 6.3.2.3. > > > > 6.3.2.3 does not mention dereferencing at all; it only addresses pointer > > conversion. Dereferencing is defined in 6.5.3.2.
and I'd say that it is also covered by 6.2.6.1 (together with 6.5p7). > > But let me ask you this. What do you think 6.5 paragraph 7 means? For > > example, are you also of the opinion that this is illegal? > > > > int i; > > unsigned int *pui = (unsigned int*)&i; > > unsigned int ui = *pui; > > That's covered by 6.3.2.3 Para 2. This paragraph is about pointer conversion, not dereferencing. -- Vincent Lefèvre <vinc...@vinc17.net> - Web: <http://www.vinc17.net/> 100% accessible validated (X)HTML - Blog: <http://www.vinc17.net/blog/> Work: CR INRIA - computer arithmetic / Arénaire project (LIP, ENS-Lyon)
