Re: Using the GNU GMP Library for Bignums in Emacs

[Paul Eggert]

Markus Triska wrote:

> Using GMP has a significant downside if you run out of memory: There’s
> currently no defined way for the allocation functions to recover from an
> error such as out of memory, they must *terminate* program execution.

This should not be a problem if we use GMP's mpn_* functions. They never 
allocate memory; it is the user's responsibility to allocate it. This should fit 
better with how Emacs does things internally.

> Also, it may become hard to stop long GMP calculations, whereas you can
> easily stop computations that are written in Elisp. Thus, long GMP
> calculations may lead to denial of editing attacks.

Yes, this could be a problem. Perhaps we'll need to extend GMP to fix it. On the 
other hand, no doubt there are other, similar problems in GNU Emacs (just look 
for calls to memcpy :-), and perhaps this problem could just be added to the list.