diff --git a/appl/ftp/common/common.h b/appl/ftp/common/common.h
index 5b9c8be52..f8ca5274b 100644
--- a/appl/ftp/common/common.h
+++ b/appl/ftp/common/common.h
@@ -47,4 +47,6 @@
 
 #include "base64.h"
 
+void set_buffer_size(int, int);
+
 #endif /* __COMMON_H__ */