incf-pointer

incf-pointer

Syntax

Macro: incf-pointer place &optional (offset 1) ⇒ new-pointer

Arguments and Values

place

A setf place.

new-pointer

A foreign pointer.

offset

An integer.

Description

The incf-pointer macro takes the foreign pointer from place and creates a new-pointer incremented by offset bytes and which is stored in place.

Examples

  CFFI> (defparameter *two-words* (foreign-string-alloc "Common Lisp"))
  ⇒ *TWO-WORDS*
  CFFI> (defparameter *one-word* *two-words*)
  ⇒ *ONE-WORD*
  CFFI> (incf-pointer *one-word* 7)
  ⇒ #.(SB-SYS:INT-SAP #X00600457)
  CFFI> (foreign-string-to-lisp *one-word*)
  ⇒ "Lisp"
  CFFI> (foreign-string-to-lisp *two-words*)
  ⇒ "Common Lisp"

See Also

inc-pointer
make-pointer
pointerp
null-pointer
null-pointer-p