Add call-with-sigint

knots.scm

@@ -1,8 +1,11 @@
 (define-module (knots)
   #:use-module (ice-9 suspendable-ports)
+  #:use-module (fibers conditions)
   #:export (call-with-default-io-waiters
 
-            wait-when-system-clock-behind))
+            wait-when-system-clock-behind
+
+            call-with-sigint))
 
 (define (call-with-default-io-waiters thunk)
   (parameterize
@@ -19,3 +22,18 @@
       (simple-format (current-error-port)
                      "warning: system clock potentially behind, waiting\n")
       (sleep 20))))
+
+;; Copied from (fibers web server)
+(define (call-with-sigint thunk cvar)
+  (let ((handler #f))
+    (dynamic-wind
+      (lambda ()
+        (set! handler
+          (sigaction SIGINT (lambda (sig) (signal-condition! cvar)))))
+      thunk
+      (lambda ()
+        (if handler
+            ;; restore Scheme handler, SIG_IGN or SIG_DFL.
+            (sigaction SIGINT (car handler) (cdr handler))
+            ;; restore original C handler.
+            (sigaction SIGINT #f))))))