On 01/05/2010 02:09 AM, Joshua Haberman wrote: > Erik Trulsson <ertr1013 <at> student.uu.se> writes: >> On Mon, Jan 04, 2010 at 08:17:00PM +0000, Joshua Haberman wrote: >>> The text you quoted does not contain any "shall not" language about >>> dereferencing, so this conclusion does not follow. >> >> It doesn't have to use any "shall not" language. If the standard does not >> say that any particular action is allowed or otherwise defines what it >> does, then that action implicitly has undefined behaviour. > > Section 6.5 does define circumstances under which converted pointers may > be dereferenced.
No. It says "An object shall have its stored value accessed only by an lvalue expression that has one of the following types: but (union u*)&i is not a legal lvalue expression because the dereference is undefined behaviour. You may only dereference a pointer as permitted by 6.3.2.3. Andrew.
