diff --git a/lib/libgeom/geom_getxml.c b/lib/libgeom/geom_getxml.c
index b27696d21657..17e04761b8a6 100644
--- a/lib/libgeom/geom_getxml.c
+++ b/lib/libgeom/geom_getxml.c
@@ -36,7 +36,7 @@
 #include "libgeom.h"
 
 char *
-geom_getxml()
+geom_getxml(void)
 {
 	char *p;
 	size_t l = 0;