Re: Using the GNU GMP Library for Bignums in Emacs

[Paul Eggert]

On 05/03/2018 01:30 PM, Helmut Eller wrote:
> Still convinced that "fffffffffffffefe cannot be a fixnum"?.

No, Eli's right. Emacs has never interpreted fffffffffffffefe as a 
fixnum on any practical platform, as far as I know. In Elisp code on 
practical platforms, #xfffffffffffffefe is a fixnum neither in master 
(where it is an overflow error) nor in Emacs 25 (where it is typically 
converted silently to 1.8446744073709552e+19, with some loss of 
information). If Emacs gets bignums, #xfffffffffffffefe will be lossless 
and will have the same meaning as 18446744073709551358, which is the 
standard interpretation of this hexadecimal number in C and in most 
other languages.