--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/format/c99-scanf-2.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,26 @@
+/* Test for scanf formats.  Formats using extensions to the standard
+   should be rejected in strict pedantic mode.
+*/
+/* Origin: Joseph Myers <jsm28@cam.ac.uk> */
+/* { dg-do compile } */
+/* { dg-options "-std=iso9899:1999 -pedantic -Wformat" } */
+
+#include "format.h"
+
+void
+foo (int *ip, long long int *llp, wchar_t *ls)
+{
+  /* The length modifiers q and L as applied to integer formats are
+     extensions.
+  */
+  scanf ("%qd", llp); /* { dg-warning "C" "%q length" } */
+  scanf ("%Ld", llp); /* { dg-warning "C" "%L length" } */
+  /* The conversion specifiers C and S are X/Open extensions.  */
+  scanf ("%C", ls); /* { dg-warning "C" "scanf %C" } */
+  scanf ("%S", ls); /* { dg-warning "C" "scanf %S" } */
+  /* The use of operand number $ formats is an X/Open extension.  */
+  scanf ("%1$d", ip); /* { dg-warning "C" "scanf $ format" } */
+  /* glibc also supports flags ' and I on scanf formats as an extension.  */
+  scanf ("%'d", ip); /* { dg-warning "C" "scanf ' flag" } */
+  scanf ("%Id", ip); /* { dg-warning "C" "scanf I flag" } */
+}