mfbt/IntegerPrintfMacros.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   4  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 /* Implements the C99 <inttypes.h> interface, minus the SCN* format macros. */
   7
   8 #ifndef mozilla_IntegerPrintfMacros_h_
   9 #define mozilla_IntegerPrintfMacros_h_
  10
  11 /*
  12  * MSVC++ doesn't include <inttypes.h>, even in versions shipping <stdint.h>, so
  13  * we have to reimplement it there.  Note: <inttypes.h> #includes <stdint.h>.
  14  *
  15  * Note that this header DOES NOT implement <inttypes.h>'s scanf macros.  MSVC's
  16  * scanf doesn't have sufficient format specifier support to implement them
  17  * (specifically, to implement scanning into an 8-bit location).
  18  *
  19  * http://stackoverflow.com/questions/3036396/scanfd-char-char-as-int-format-string
  20  *
  21  * Moreover, scanf is a footgun: if the input number exceeds the bounds of the
  22  * target type, behavior is undefined (in the compiler sense: that is, this code
  23  * could overwrite your hard drive with zeroes):
  24  *
  25  *   uint8_t u;
  26  *   sscanf("256", "%" SCNu8, &u); // BAD
  27  *
  28  * This header will sometimes provide SCN* macros, by dint of being implemented
  29  * using <inttypes.h>.  But for these reasons, *never* use them!
  30  */
  31
  32 #if defined(MOZ_CUSTOM_INTTYPES_H)
  33 #  include MOZ_CUSTOM_INTTYPES_H
  34 #elif defined(_MSC_VER)
  35 #  include "mozilla/MSIntTypes.h"
  36 #else
  37 #  include <inttypes.h>
  38 #endif
  39
  40 #endif  /* mozilla_IntegerPrintfMacros_h_ */