Hi, On Fri, 20 Jan 2017, Richard Henderson wrote:
> > You can't have a 4-aligned type of size 3. Sizes must be multiples of > > alignment (otherwise arrays don't work). The type of a 3-sized field > > in a packed struct that syntactically might be a 4-aligned type (e.g. > > by using attributes on char-array types) is actually a different type > > having an alignment of 1. It's easier to simply regard all types > > inside packed structs as 1-aligned (which is IMO what we try to do). > > > > That is, the byte after a 4-aligned "3-sized" type is always padding. > > [ I read Bin Fan's original email some months ago, but I don't have it handy > now. Take faulty memory with a grain of salt. ] > > I thought this was about libatomic being presented with an unaligned 3-byte > structure that happens to sit within an aligned 4-byte word, and choosing to > atomically operate on the 4-byte word instead of taking a lock on the side. Ah well, in that case I lost context as well ;) Ciao, Michael.
