我写了一个非常简单的printf uint64_t测试代码:
#include <inttypes.h>
#include <stdio.h>
int main()
{
uint64_t ui64 = 90;
printf("test uint64_t : %" PRIu64 "\n", ui64);
return 0;
}
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我使用ubuntu 11.10(64位)和gcc版本4.6.1进行编译,但失败了:
main.cpp: In function ‘int main()’:
main.cpp:9:30: error: expected ‘)’ before ‘PRIu64’
main.cpp:9:47: warning: spurious trailing ‘%’ in format [-Wformat]
Run Code Online (Sandbox Code Playgroud) 我在GNU的C++编译器上尝试这个代码,我无法理解它的行为:
#include <stdio.h>;
int main()
{
int num1 = 1000000000;
long num2 = 1000000000;
long long num3;
//num3 = 100000000000;
long long num4 = ~0;
printf("%u %u %u", sizeof(num1), sizeof(num2), sizeof(num3));
printf("%d %ld %lld %llu", num1, num2, num3, num4);
return 0;
}
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当我取消注释注释行时,代码不会编译并给出错误:
错误:对于long类型,整数常量太大
但是,如果代码按原样编译并执行,则会产生远大于10000000000的值.
为什么?