[c/c++][Linux] 时间戳转换为tm,time_t,timeval

ref

https://blog.youkuaiyun.com/GreenTeemo/article/details/102586265

说明

时间戳为2020/03/25 11:09:42 .761197，其中.761197为微秒。

code

#include <stdio.h>
#include <time.h>
#include <sys/time.h>

int main()
{
    char time[100] = "2020/03/25 11:09:42 .761197";
    char time_format[100] = "%Y/%m/%d %H:%M:%S";
    printf("origin  is %s\n", time);

    /* to tm */
    struct tm tm;
    strptime(time, time_format, &tm);
    printf("tm      is %04d-%02d-%02d %02d:%02d:%02d\n", 1900 + tm.tm_year, 1 + tm.tm_mon, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);

    /* to time_t */
    time_t tt;
    tt = mktime(&tm);
    printf("time_t  is %lu\n", tt);

    /* to timeval */
    struct timeval tv;
    tv.tv_sec = tt;
    tv.tv_usec = atoi(time + 21);		// 21 = strlen("2020/03/25 11:09:42 .")
    printf("timeval is %ld.%06ld\n", tv.tv_sec, tv.tv_usec);

    return 0;
}

output

origin  is 2020/03/25 11:09:42 .761197
tm      is 2020-03-25 11:09:42
time_t  is 1585105782
timeval is 1585105782.761197