如何将数据读入一个time_t的使用可变scanf（）的？ [英] How to read data into a time_t variable using scanf()?

问题描述

这code给我的警告：

This code gives me warnings:

$ cat test.c
#include<stdio.h>
#include<time.h>

int main() {

    time_t t;
    scanf("%lld", &t);
    printf("%lld\n", t);
    return 0;
}
$ gcc test.c -o test
test.c: In function ‘main’:
test.c:7: warning: format ‘%lld’ expects type ‘long long int *’, but argument 2 has type ‘time_t *’
test.c:8: warning: format ‘%lld’ expects type ‘long long int’, but argument 2 has type ‘time_t’
$ 

除了警告，在code正常工作。

Apart from the warnings, the code works as expected.

我应该怎么做才能不下去了编译警告（没有编译器编译招数讨好）？

What should I do to not get the warnings on compilation (no compiler pragma tricks please)?

推荐答案

time_t的的确切类型取决于您的平台和操作系统上。它仍然是相当频繁的32位（或 INT 或长），而不是64，有的甚至使用花车。做正确的事情是读入一个已知大小的整数（ INT 或长长），然后分配的值以一个 time_t的作为第二步骤

The exact type of time_t depends on your platform and OS. It's still quite often 32 bit (either int or long), not 64, and some even use floats. The correct thing to do is to read into a known-size integer (either int or long long) and then assign the value to a time_t as a second step.

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