c - getdate 和 ctime 无法正常工作

Question

这是我的程序 time_play.c :

#include <stdlib.h>
#include <stdio.h>
#include <time.h>

int
main (void)
{
    char *time_str = "2011-07-20 17:30:18";
    time_t time_tm = getdate(time_str);

    printf("str: %s and time: %s \n", time_str, ctime(&time_tm));

    return 0;
} 

它的输出:

$ gcc -o time_play time_play.c 
$ ./time_play
str: 2011-07-20 17:30:18 and time: Wed Dec 31 16:00:00 1969

可以看出，time 的值为 NULL。为什么会这样？

Answer 1

您是否创建了一个模板文件来指定您正在使用的日期格式？

来自手册页:

User-supplied templates are used to parse and interpret the input string. The templates are text files created by the user and identified via the environment variable DATEMSK.

创建一个类似 timetemplate.txt 的文件:

%Y-%m-%d %H:%M:%S

然后设置DATEMSK的值指向它:

export DATEMSK=/home/somebody/timetemplate.txt

这段代码在 OS X 上对我有用，结合设置 DATEMSK:

#include <stdlib.h>
#include <stdio.h>
#include <time.h>

int main (void)
{
  char *time_str = "2011-07-20 17:30:18";
  struct tm *time_tm = getdate(time_str);
  time_t t = mktime(time_tm);

  printf("str: %s and time: %s", time_str, ctime(&t));
  return 0;
}