diff --git a/src/structs.h b/src/structs.h
index 250dc2f..423757a 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -4831,7 +4831,7 @@
 #define DELETION_REGISTER	36
 #ifdef FEAT_CLIPBOARD
 # define STAR_REGISTER		37
-#  ifdef FEAT_X11
+#  if defined(FEAT_X11) || defined(FEAT_WAYLAND)
 #   define PLUS_REGISTER	38
 #  else
 #   define PLUS_REGISTER	STAR_REGISTER	    // there is only one
@@ -5187,3 +5187,23 @@
     int cs_ypixel;
 };
 #endif
+
+#ifdef FEAT_WAYLAND
+
+// Wayland selections
+typedef enum {
+    WAYLAND_SELECTION_NONE	    = 0x0,
+    WAYLAND_SELECTION_REGULAR	    = 0x1,
+    WAYLAND_SELECTION_PRIMARY	    = 0x2,
+} wayland_selection_T;
+
+// Callback when another client wants us to send data to them
+typedef void (*wayland_cb_send_data_func_T)(
+	const char *mime_type,
+	int fd,
+	wayland_selection_T type);
+
+// Callback when the selection is lost (data source object overwritten)
+typedef void (*wayland_cb_selection_cancelled_func_T)(wayland_selection_T type);
+
+#endif // FEAT_WAYLAND