On 8 September 2013 14:22, JimJoyce wrote: > Thanks, Jonathan, for your speedy reply. > > However, I'm surprised, That 'C' can pad structures as it sees fit. > I thought the point and value of user-defined structures was to suit user's > needs. > not the whim of the compiler.. It's not the whim of the compiler, it's due to the hardware. See http://c-faq.com/struct/padding.html and the links on that page. > I think you're telling me that '__attribute__((__packed__))' is what I > need to do to force the compiler to do things my way? Yes, but that's not portable and might slow the code down if the hardware has to perform unaligned accesses to doubles.
