On Mon, Oct 01, 2018 at 09:16:33AM +0100, Andrew Haley wrote: > On 09/30/2018 06:44 PM, sundaresh wrote: > > Why do struct's take up a lot more memory than the sum of the sizes of its > > members ? This increases by even a lot more the larger the struct gets . If > > the compiler is doing padding or aligning I would like to disable and not > > have that at all since it is unnecessarily wasteful of memory ? I > > encountered a similar problem when declaring floating point variables > > independently outside a struct. The problem becomes worse if these floating > > point variables are struct members. > > Alignment, usually. But it's worth noting that GCC follows the system > ABI specfication for laying out structures in memory. We usually don't > get to decide how it's done. It also sounds like sundaresh is dealing with x87 doubles. Segher
