"Darren Rook" <route66@xxxxxxxxx> writes: > On Fri, Jan 16, 2009 at 10:33 AM, Ian Lance Taylor <iant@xxxxxxxxxx> wrote: > >>> Is there some method to tell the compiler that *val may not be word >>> aligned, so the compiler can generate code to work around the >>> alignment issue (instead of assuming the *val will be word aligned)? >> >> No. Avoid writing this sort of code. > > I thought as much. > > Then why is attribute((packed)) provided? I really don't see a use > for it. Why not rename it to __attribute__((addressviolation))? The potential address violation only occurs when you take the address of a field and pass it to another function. There are many ways to use structures without taking the address of a field. There are two main reasons to use __attribute__ ((packed)). The first is to minimize the amount of memory used by a data structure, typically when using the struct in a large array. The second is to make the struct mimic a data layout which is imposed externally, such as when accessing memory mapped hardware. Ian
