diff --git a/lib/system/embedded.nim b/lib/system/embedded.nim
index 46e84e056..a14f43e7e 100644
--- a/lib/system/embedded.nim
+++ b/lib/system/embedded.nim
@@ -40,4 +40,4 @@ proc reraiseException() {.compilerRtl.} =
 
 proc writeStackTrace() = discard
 
-proc setControlCHook(hook: proc () {.noconv.}) = discard
+proc setControlCHook(hook: proc () {.noconv.} not nil) = discard