On Tue, Jul 01, 2014 at 05:01:43PM +0200, Markus Teich wrote: > Rob wrote: > > You've got alignment issues here - msg will be aligned to support any > > type (as malloc's interface specifies) so msg+1 will most likely be on > > an odd address, one byte off a highly aligned address. This means if > > your struct contains anything other than chars, you'll have UB. This is > > fine on x86, which allows unaligned access with a performance penalty > > but on something like an ARM machine you'll have issues. > > Heyho, > > so if every field in the message is a multiple of 4 bytes long, this should > fix > the problem? In this case I would just make op an uint32_t and htonl it before > sending, ntohl after receiving.
Do not assume that. It is wrong in the general case.
