1 files changed, 9 insertions, 0 deletions
diff --git a/src/nvim/api/private/defs.h b/src/nvim/api/private/defs.h
index 76ac23a521..6c8e324649 100644
--- a/src/nvim/api/private/defs.h
+++ b/src/nvim/api/private/defs.h
@@ -22,6 +22,15 @@ typedef enum {
   kErrorTypeValidation
 } ErrorType;
 
+typedef enum {
+  kMessageTypeRequest,
+  kMessageTypeResponse,
+  kMessageTypeNotification
+} MessageType;
+
+/// Used as the message ID of notifications.
+#define NO_RESPONSE UINT64_MAX
+
 typedef struct {
   ErrorType type;
   char msg[1024];