X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Fsignal.lisp;h=cc2100728e4d1958aa48bfd253604c2a67591b30;hb=cf0b72cd4052a09b9a305081524bd44e2948c1e5;hp=55eb7ca7398ffdc84e6c186d687ab774df8b5f36;hpb=4898ef32c639b1c7f4ee13a5ba566ce6debd03e6;p=sbcl.git

diff --git a/src/code/signal.lisp b/src/code/signal.lisp
index 55eb7ca..cc21007 100644
--- a/src/code/signal.lisp
+++ b/src/code/signal.lisp
@@ -40,38 +40,55 @@
 (defvar *interrupts-enabled* t)
 (defvar *interrupt-pending* nil)
 
+;;; KLUDGE: This tells INTERRUPT-THREAD that it is being invoked as an
+;;; interruption, so that if the thread being interrupted is the
+;;; current thread it knows to enable interrupts. INVOKE-INTERRUPTION
+;;; binds it to T, and WITHOUT-INTERRUPTS binds it to NIL, so that if
+;;; interrupts are disable between INTERRUPT-THREAD and this we don't
+;;; accidentally re-enable them.
+(defvar *in-interruption* nil)
+
 (sb!xc:defmacro without-interrupts (&body body)
   #!+sb-doc
-  "Execute BODY in a context impervious to interrupts."
+  "Execute BODY with all deferrable interrupts deferred. Deferrable interrupts
+include most blockable POSIX signals, and SB-THREAD:INTERRUPT-THREAD. Does not
+interfere with garbage collection, and unlike in many traditional Lisps using
+userspace threads, in SBCL WITHOUT-INTERRUPTS does not inhibit scheduling of
+other threads."
   (let ((name (gensym "WITHOUT-INTERRUPTS-BODY-")))
     `(flet ((,name () ,@body))
-      (if *interrupts-enabled*
-          (unwind-protect
-               (let ((*interrupts-enabled* nil))
-                 (,name))
-            ;; If we were interrupted in the protected section, then
-            ;; the interrupts are still blocked and it remains so
-            ;; until the pending interrupt is handled.
-            ;;
-            ;; If we were not interrupted in the protected section,
-            ;; but here, then even if the interrupt handler enters
-            ;; another WITHOUT-INTERRUPTS, the pending interrupt will
-            ;; be handled immediately upon exit from said
-            ;; WITHOUT-INTERRUPTS, so it is as if nothing has
-            ;; happened.
-            (when *interrupt-pending*
-              (receive-pending-interrupt)))
-          (,name)))))
+       (if *interrupts-enabled*
+           (unwind-protect
+                (let ((*interrupts-enabled* nil)
+                      (*in-interruption* nil))
+                  (,name))
+             ;; If we were interrupted in the protected section, then
+             ;; the interrupts are still blocked and it remains so
+             ;; until the pending interrupt is handled.
+             ;;
+             ;; If we were not interrupted in the protected section,
+             ;; but here, then even if the interrupt handler enters
+             ;; another WITHOUT-INTERRUPTS, the pending interrupt will
+             ;; be handled immediately upon exit from said
+             ;; WITHOUT-INTERRUPTS, so it is as if nothing has
+             ;; happened.
+             (when *interrupt-pending*
+               (receive-pending-interrupt)))
+           (,name)))))
 
 (sb!xc:defmacro with-interrupts (&body body)
   #!+sb-doc
   "Allow interrupts while executing BODY. As interrupts are normally allowed,
-  this is only useful inside a WITHOUT-INTERRUPTS."
+this is only useful inside a SB-SYS:WITHOUT-INTERRUPTS. Signals a runtime
+warning if used inside the dynamic countour of SB-SYS:WITHOUT-GCING."
   (let ((name (gensym)))
     `(flet ((,name () ,@body))
        (if *interrupts-enabled*
            (,name)
-           (let ((*interrupts-enabled* t))
-             (when *interrupt-pending*
-               (receive-pending-interrupt))
-             (,name))))))
+           (progn
+             (when sb!kernel:*gc-inhibit*
+               (warn "Re-enabling interrupts while GC is inhibited."))
+             (let ((*interrupts-enabled* t))
+               (when *interrupt-pending*
+                 (receive-pending-interrupt))
+               (,name)))))))