11.5 Integers and Characters

Integer and character Lisp objects are created from integers using the macros XSETINT() and XSETCHAR() or the equivalent functions make_int() and make_char(). (These are actually macros on most systems.) These functions basically just do some moving of bits around, since the integral value of the object is stored directly in the Lisp_Object.

XSETINT() and the like will truncate values given to them that are too big; i.e. you won’t get the value you expected but the tag bits will at least be correct.