2.3.1 Integer Type

The range of values for integers in Emacs Lisp is −134217728 to 134217727 (28 bits; i.e., -2**27 to 2**27 - 1) on most machines. (Some machines may provide a wider range.) It is important to note that the Emacs Lisp arithmetic functions do not check for overflow. Thus (1+ 134217727) is −134217728 on most machines.

The read syntax for integers is a sequence of (base ten) digits with an optional sign at the beginning and an optional period at the end. The printed representation produced by the Lisp interpreter never has a leading ‘+’ or a final ‘.’.

     -1               ; The integer -1.
     1                ; The integer 1.
     1.               ; Also the integer 1.
     +1               ; Also the integer 1.
     268435457        ; Also the integer 1 on a 28-bit implementation.

See Numbers, for more information.