1 files changed, 1 insertions, 1 deletions

diff --git a/sys/geom/geom.h b/sys/geom/geom.h
index 76ebcb62b0840..5b5562435d625 100644
--- a/sys/geom/geom.h
+++ b/sys/geom/geom.h
@@ -348,7 +348,7 @@ void gctl_set_param_err(struct gctl_req *req, const char *param, void const *ptr
 void *gctl_get_param(struct gctl_req *req, const char *param, int *len);
 char const *gctl_get_asciiparam(struct gctl_req *req, const char *param);
 void *gctl_get_paraml(struct gctl_req *req, const char *param, int len);
-int gctl_error(struct gctl_req *req, const char *fmt, ...);
+int gctl_error(struct gctl_req *req, const char *fmt, ...) __printflike(2, 3);
 struct g_class *gctl_get_class(struct gctl_req *req, char const *arg);
 struct g_geom *gctl_get_geom(struct gctl_req *req, struct g_class *mpr, char const *arg);
 struct g_provider *gctl_get_provider(struct gctl_req *req, char const *arg);