在OS X上的printf和％llu对％lu [英] printf and %llu vs %lu on OS X

问题描述

可能重复：

如何printf uint64_t？

为什么我在64位的Mac（我使用Clang） uint64_t 类型是 unsigned long long uint64_t 类型是 unsigned long ？

Why is it that on my 64-bit Mac (I am using Clang) the uint64_t type is unsigned long long while on 64-bit Ubuntu the uint64_t type is unsigned long?

这让我很难得到我的 printf 调用不给编译器警告工作）。

This makes it very difficult for me to get my printf calls to not give compiler warnings (or indeed even to work) under both environments.

我可以尝试使用宏尝试选择正确的字符串（ #define LU c>％llu 或％lu ，并且在处理丑陋的 printf 在Mac上我有一个64位字大小（因此 _LP64 将被定义， UINTPTR_MAX！= 0xffffffff ），但它仍然使用 long long 用于64位int类型。

I can try to use macros to try to choose the correct string (#define LU either %llu or %lu, and in the process uglifying the printf strings a bit) but on the Mac I've got a 64-bit word size (so _LP64 would be defined and UINTPTR_MAX != 0xffffffff) and yet it still uses long long for the 64 bit int types.

// printf macro switch (for the uint64_t's)
#if UINTPTR_MAX == 0xffffffff 
   // 32-bit
#  define LU "%llu"
#else 
   // assume 64-bit
   // special case for OS X because it is strange
   // should actually check also for __MACH__ 
#  ifdef __APPLE__
#    define LU "%llu"
#  else
#    define LU "%lu"
#  endif
#endif

推荐答案

在< cinttypes> 。尝试

printf("%"PRIu64, x);

或者更好的是使用C ++的功能，如

Or, even better, use C++ features like

std::cout << x;

这将选择正确的<您的变量类型的运算符。

which will select the proper << operator for your variable type.

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