如何打印在C型的int64_t [英] How to print a int64_t type in C

问题描述

C99标准具有整数类型的字节大小一样的int64_t。我使用下面的code：

C99 standard has integer types with bytes size like int64_t. I am using the following code:

#include <stdio.h>
#include <stdint.h>
int64_t my_int = 999999999999999999;
printf("This is my_int: %I64d\n", my_int);

和我得到这个编译器警告：

and I get this compiler warning:

warning: format ‘%I64d’ expects type ‘int’, but argument 2 has type ‘int64_t’

我试着用：

printf("This is my_int: %lld\n", my_int); // long long decimal

但我得到同样的警告。我使用该编译器：

But I get the same warning. I am using this compiler:

~/dev/c$ cc -v
Using built-in specs.
Target: i686-apple-darwin10
Configured with: /var/tmp/gcc/gcc-5664~89/src/configure --disable-checking --enable-werror --prefix=/usr --mandir=/share/man --enable-languages=c,objc,c++,obj-c++ --program-transform-name=/^[cg][^.-]*$/s/$/-4.2/ --with-slibdir=/usr/lib --build=i686-apple-darwin10 --program-prefix=i686-apple-darwin10- --host=x86_64-apple-darwin10 --target=i686-apple-darwin10 --with-gxx-include-dir=/include/c++/4.2.1
Thread model: posix
gcc version 4.2.1 (Apple Inc. build 5664)

我应该使用哪种格式打印my_int变量无需警告？

Which format should I use to print my_int variable without having a warning?

推荐答案

有关的int64_t 键入

#include <inttypes.h>
int64_t t;
printf("%" PRId64 "\n", t);

为 uint64_t中类型：

#include <inttypes.h>
uint64_t t;
printf("%" PRIu64 "\n", t);

您也可以使用 PRIx64 十六进制打印。

you can also use PRIx64 to print in hexadecimal.

CP preference.com有可用的宏的完整列表所有类型，包括使用intptr_t （ PRIxPTR ）。有对scanf的单独宏，如 SCNd64 。

cppreference.com has a full listing of available macros for all types including intptr_t (PRIxPTR). There are separate macros for scanf, like SCNd64.

PRIu16的典型定义是胡，那么隐含的字符串常量毗连发生在编译​​时。

A typical definition of PRIu16 would be "hu", so implicit string-constant concatenation happens at compile time.

有关您的code是完全可移植，你必须使用 PRId32 等印刷 int32_t 和％D或印刷类似 INT 。

For your code to be fully portable, you must use PRId32 and so on for printing int32_t, and "%d" or similar for printing int.

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