;; readtable configured so that the system sources can be read.
; :sb-show
- ;; Build SBCL with the old CMU CL low level debugger, "ldb". If
- ;; are aren't messing with CMU CL at a very low level (e.g.
- ;; trying to diagnose GC problems, or trying to debug assembly
- ;; code for a port to a new CPU) you shouldn't need this.
+ ;; Build SBCL with the old CMU CL low level debugger, "ldb". If are
+ ;; aren't messing with SBCL at a very low level (e.g., trying to
+ ;; diagnose GC problems, or trying to debug assembly code for a port
+ ;; to a new CPU) you shouldn't need this.
; :sb-ldb
;; This isn't really a target Lisp feature at all, but controls
;; As of SBCL 0.8, this is only supposed to work in x86 Linux, on which
;; system it's implemented using clone(2) and the %fs segment register.
;; Note that no consistent effort to audit the SBCL library code for
- ;; thread safety has been performed, so caveat executor
+ ;; thread safety has been performed, so caveat executor.
; :sb-thread
+
+ ;; Kernel support for futexes (so-called "fast userspace mutexes") is
+ ;; available in Linux 2.6 and some versions of 2.4 (Red Hat vendor
+ ;; kernels, possibly other vendors too). We can take advantage of
+ ;; these to do faster and probably more reliable mutex and condition
+ ;; variable support. An SBCL built with this feature will fall back
+ ;; to the old system if the futex() syscall is not available at
+ ;; runtime
+ ; :sb-futex
+
+ ;; Support for detection of unportable code (when applied to the
+ ;; COMMON-LISP package, or SBCL-internal pacakges) or bad-neighbourly
+ ;; code (when applied to user-level packages), relating to material
+ ;; alteration to packages or to bindings in symbols in packages.
+ :sb-package-locks
+
+ ;; Support for the entirety of the 21-bit character space defined by
+ ;; the Unicode consortium, rather than the classical 8-bit ISO-8859-1
+ ;; character set.
+ :sb-unicode
;; This affects the definition of a lot of things in bignum.lisp. It
;; doesn't seem to be documented anywhere what systems it might apply
;; to. It doesn't seem to be needed for X86 systems anyway.
; :32x16-divide
- ;; This is probably true for some processor types, but not X86. It
- ;; affects a lot of floating point code.
- ; :negative-zero-is-not-zero
-
;; This is set in classic CMU CL, and presumably there it means
;; that the floating point arithmetic implementation
;; conforms to IEEE's standard. Here it definitely means that the
;; in the *FEATURES* list
;;
+ ;; Any target feature which affects binary compatibility of fasl files
+ ;; needs to be recorded in *FEATURES-POTENTIALLY-AFFECTING-FASL-FORMAT*
+ ;; (elsewhere).
+
;; notes on the :NIL and :IGNORE features:
;;
;; #+NIL is used to comment out forms. Occasionally #+IGNORE is used
;; :control-stack-grows-downward-not-upward
;; On the X86, the Lisp control stack grows downward. On the
;; other supported CPU architectures as of sbcl-0.7.1.40, the
- ;; system stack grows upward.
+ ;; system stack grows upward.
;; Note that there are other stack-related differences between the
;; X86 port and the other ports. E.g. on the X86, the Lisp control
;; stack coincides with the C stack, meaning that on the X86 there's
;; just parameterized by #!+X86, but it'd probably be better to
;; use new flags like :CONTROL-STACK-CONTAINS-C-STACK.
;;
+ ;; :stack-allocatable-closures
+ ;; The compiler can allocate dynamic-extent closures on stack.
+ ;;
;; operating system features:
;; :linux = We're intended to run under some version of Linux.
;; :bsd = We're intended to run under some version of BSD Unix. (This
;; particular version of BSD we're intended to run under.)
;; :freebsd = We're intended to run under FreeBSD.
;; :openbsd = We're intended to run under OpenBSD.
+ ;; :netbsd = We're intended to run under NetBSD.
;; :sunos = We're intended to run under Solaris user environment
;; with the SunOS kernel.
;; :osf1 = We're intended to run under Tru64 (aka Digital Unix
projects / sbcl.git / blobdiff