diff --git a/src/structs.h b/src/structs.h
index eb72f90..802180b 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -1373,11 +1373,12 @@
 };
 
 /*
- * Options for job commands.
+ * Options for job and channel commands.
  */
 typedef struct
 {
-    ch_mode_T	jo_mode;
+    ch_mode_T	jo_mode;	/* "mode" */
+    char_u	*jo_callback;	/* "callback", not allocated! */
 } jobopt_T;