diff --git a/src/regexp.c b/src/regexp.c
index e33e0cf..0798f02 100644
--- a/src/regexp.c
+++ b/src/regexp.c
@@ -5026,7 +5026,7 @@
 					    reg_startpos[no].col,
 					    reg_endpos[no].lnum,
 					    reg_endpos[no].col,
-					    NULL);
+					    &len);
 			}
 		    }
 		}