diff --git a/gdump.c b/gdump.c
index 7e02d391f..88942f3aa 100644
--- a/gdump.c
+++ b/gdump.c
@@ -37,6 +37,9 @@
 
 #include <string.h>
 
+static void
+escaped_printf (GOutputStream *out, const char *fmt, ...) G_GNUC_PRINTF (2, 3);
+
 static void
 escaped_printf (GOutputStream *out, const char *fmt, ...)
 {