Use C99 standard format macros for 64-bit values.

base/format_macros.h

+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_FORMAT_MACROS_H_
+#define BASE_FORMAT_MACROS_H_
+
+// This file defines the C99 format macros for 64-bit values. If you wish to
+// print a 64-bit value in a portable way do:
+//   int64_t value;
+//   printf("xyz:%" PRId64, value);
+//
+// For wide strings, prepend "Wide" to the macro:
+//   int64_t value;
+//   StringPrintf(L"xyz: %" WidePRId64, value);
+
+#include "build/build_config.h"
+
+#if defined(OS_POSIX)
+
+#if defined(_INTTYPES_H) && !defined(PRId64)

[Mark Mentovai, 2009/06/25 18:02:18]

There's no standard for system header guards - this doesn't match the guard
style used on Mac OS X.

+#error "inttypes.h has already been included before this header file, but "
+#error "without __STDC_FORMAT_MACROS defined."
+#endif
+
+#if !defined(__STDC_FORMAT_MACROS)
+#define __STDC_FORMAT_MACROS
+#endif
+
+#include <inttypes.h>
+
+// GCC will concatenate wide and narrow strings correctly, so nothing needs to
+// be done here.
+#define WidePRId64 PRId64
+#define WidePRIu64 PRIu64
+#define WidePRIx64 PRIx64
+
+#else  // OS_WIN
+
+#define PRId64 "I64d"
+#define PRIu64 "I64u"
+#define PRIx64 "I64x"
+
+#define WidePRId64 L"I64d"
+#define WidePRIu64 L"I64u"
+#define WidePRIx64 L"I64x"
+
+#endif
+
+#endif  // !BASE_FORMAT_MACROS_H_