Tags: patch The memory-limit function has an implementation that is a relic of long-ago days when the heap was allocated via sbrk. This assumption is often no longer true now that ASLR is popular, and once we get portable dumping work it'll be true even less often. Since memory-limit returns nonsense so often and since nobody cares, we can and should mark memory-limit as obsolete. On its way out we can move it to a Lisp implementation and cause it to be at least somewhat more plausible. Proposed patches attached. The first patch moves memory-limit to Lisp, the second one marks it obsolete. I didn't know where to put the Lisp implementation so I put it into lisp/subr.el.