diff -r 000000000000 -r 6474c204b198 mfbt/IntegerPrintfMacros.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mfbt/IntegerPrintfMacros.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,40 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* Implements the C99 <inttypes.h> interface, minus the SCN* format macros. */
+
+#ifndef mozilla_IntegerPrintfMacros_h_
+#define mozilla_IntegerPrintfMacros_h_
+
+/*
+ * MSVC++ doesn't include <inttypes.h>, even in versions shipping <stdint.h>, so
+ * we have to reimplement it there.  Note: <inttypes.h> #includes <stdint.h>.
+ *
+ * Note that this header DOES NOT implement <inttypes.h>'s scanf macros.  MSVC's
+ * scanf doesn't have sufficient format specifier support to implement them
+ * (specifically, to implement scanning into an 8-bit location).
+ *
+ * http://stackoverflow.com/questions/3036396/scanfd-char-char-as-int-format-string
+ *
+ * Moreover, scanf is a footgun: if the input number exceeds the bounds of the
+ * target type, behavior is undefined (in the compiler sense: that is, this code
+ * could overwrite your hard drive with zeroes):
+ *
+ *   uint8_t u;
+ *   sscanf("256", "%" SCNu8, &u); // BAD
+ *
+ * This header will sometimes provide SCN* macros, by dint of being implemented
+ * using <inttypes.h>.  But for these reasons, *never* use them!
+ */
+
+#if defined(MOZ_CUSTOM_INTTYPES_H)
+#  include MOZ_CUSTOM_INTTYPES_H
+#elif defined(_MSC_VER)
+#  include "mozilla/MSIntTypes.h"
+#else
+#  include <inttypes.h>
+#endif
+
+#endif  /* mozilla_IntegerPrintfMacros_h_ */