diff --git a/ffi/event_thread.nim b/ffi/event_thread.nim
index cab1f2c..921555b 100644
--- a/ffi/event_thread.nim
+++ b/ffi/event_thread.nim
@@ -47,7 +47,8 @@ proc emitLivenessEvent[T, P](ctx: ptr FFIContext[T], name: string, payload: P) =
       chronicles.error "liveness event encode failed", name = name, err = exc.msg
       return
   let dataPtr: pointer =
-    if event.len > 0: unsafeAddr event[0] else: nil
+    if event.len > 0: cast[pointer](unsafeAddr event[0])
+    else: cast[pointer](emptyListenerPayload)
   ctx.dispatchToListeners(name, dataPtr, event.len)
 
 proc onNotResponding*(ctx: ptr FFIContext) =
diff --git a/ffi/ffi_context.nim b/ffi/ffi_context.nim
index bbc512b..811b920 100644
--- a/ffi/ffi_context.nim
+++ b/ffi/ffi_context.nim
@@ -133,7 +133,7 @@ proc initContextResources*[T](ctx: ptr FFIContext[T]): Result[void, string] =
     return err("failed to create the event thread: " & getCurrentExceptionMsg())
 
   success = true
-  ok()
+  return ok()
 
 proc fireOrErr(sig: ThreadSignalPtr, name: string): Result[void, string] =
   let fired = sig.fireSync().valueOr:
@@ -176,7 +176,7 @@ proc stopAndJoinThreads*[T](ctx: ptr FFIContext[T]): Result[void, string] =
   joinThread(ctx.ffiThread)
   ?ctx.eventThreadExitSignal.waitExitOrErr("event thread", ThreadExitTimeout)
   joinThread(ctx.eventThread)
-  ok()
+  return ok()
 
 proc clearContext[T](ctx: ptr FFIContext[T]): Result[void, string] =
   ## Stops a heap-allocated FFI context.
@@ -184,4 +184,4 @@ proc clearContext[T](ctx: ptr FFIContext[T]): Result[void, string] =
     return err("clearContext: " & $error)
   ctx.cleanUpResources().isOkOr:
     return err("cleanUpResources failed: " & $error)
-  ok()
+  return ok()
diff --git a/ffi/ffi_events.nim b/ffi/ffi_events.nim
index 8c92f7e..4ea4b5b 100644
--- a/ffi/ffi_events.nim
+++ b/ffi/ffi_events.nim
@@ -178,7 +178,7 @@ proc eventQueueLen*(q: var EventQueue): int {.raises: [], gcsafe.} =
     return q.count
 
 
-const emptyListenerPayload: cstring = ""
+const emptyListenerPayload*: cstring = ""
   ## Non-nil zero-length buffer handed to listeners when a payload is
   ## empty, so a consumer doing `std::string(data, len)` / `memcpy` never
   ## receives a nil pointer (which is UB even at len 0).
@@ -197,7 +197,8 @@ proc notifyListeners*(
 
 proc notifyListenersErr*(listeners: seq[FFIEventListener], msg: string) =
   let p =
-    if msg.len > 0: cast[pointer](unsafeAddr msg[0]) else: nil
+    if msg.len > 0: cast[pointer](unsafeAddr msg[0])
+    else: cast[pointer](emptyListenerPayload)
   notifyListeners(listeners, RET_ERR, p, msg.len)
 
 var ffiCurrentEventRegistry* {.threadvar.}: ptr FFIEventRegistry