move CAN-PROBABLY-FORK to CONNECTION.FORK

Signed-off-by: Sean Whitton <spwhitton@spwhitton.name>

1 files changed, 10 insertions, 0 deletions

diff --git a/src/connection/fork.lisp b/src/connection/fork.lisp
index 702ca96..6a4ad0c 100644
--- a/src/connection/fork.lisp
+++ b/src/connection/fork.lisp
@@ -31,6 +31,16 @@
   ;; (values PID EXIT-STATUS), as SB-POSIX:WAITPID does
   #+sbcl (sb-posix:waitpid pid options))
 
+(defun can-probably-fork ()
+  "Return nil if we can detect other running threads, and the Lisp
+implementation is known not to support forking when there are other threads.
+A return value other than nil indicates only that we couldn't detect
+circumstances in which it is known that we cannot fork, not that we are sure
+we can fork -- a thread might be only partly initialised at the time we check,
+for example, such that we don't see it."
+  (and
+   #+sbcl (> 2 (length (sb-thread:list-all-threads)))))
+
 (defmacro with-fork-connection ((remaining) &body forms)
   `(progn
      (unless (lisp-connection-p)