It's this: http://nakkaya.com/2010/08/24/a-micro-manual-for-lisp-implemented-in-c/#comment-70938308 http://nakkaya.com/2010/08/24/a-micro-manual-for-lisp-implem

It's this: http://nakkaya.com/2010/08/24/a-micro-manual-for-lisp-implemented-in-c/#comment-70938308 http://nakkaya.com/2010/08/24/a-micro-manual-for-lisp-implem... I suspect Red Hat's gcc is aligning structure members on 64-bit boundaries.