请教大家，在linux下编程，用什么方法可以设置系统时间？__printf_outb_tmp_outb_wxy_0x70_

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请教大家，在linux下编程，用什么方法可以设置系统时间？

来源: 互联网发布时间：2015-10-21

本文导语: 我刚开始在linux下编程，用的是C语言。我想修改系统时间，怎么样可以做到呢？我查了很久，也没有查到。看到C库里的函数，都是怎么样获取系统时间的，没有能设置系统时间。请大家帮忙了，谢谢大家！ ...

我刚开始在linux下编程，用的是C语言。

我想修改系统时间，怎么样可以做到呢？

我查了很久，也没有查到。

看到C库里的函数，都是怎么样获取系统时间的，没有能设置系统时间。

请大家帮忙了，谢谢大家！

设置BIOS时钟示例：（注意：注释中的代码）
#include
#include
//#include

#define InttoBCD(a) ((a)/10)*16+((a)%10)
//unsigned int InttoBCD(int a);
int set_time ();

#ifndef _ASM_IO_H
#define _ASM_IO_H
#include
static __inline void
outb_wxy (unsigned char value, unsigned short int port)
{
  //__asm__ __volatile__("outb %b0,%w1nt"
  //                     "outb %%al,$0x80n"
  //                     :
  //                   :"a" (value), "Nd" (port));
  __asm__ __volatile__ ("outb %%al,%%dx"::"a" (value), "d" (port));
}
#endif
/*
unsigned int InttoBCD(int a)
{
    return (a/10)*16+(a%10);
}
*/
int
set_time ()
{
  unsigned char year, month, day, hour, minute, second;
  unsigned int retv;
  unsigned short tmp;

  printf ("Date format:year-month-day hour-minute-secondn");
  printf ("            2-7-18 14-30-50 = 2002/7/18 14:30:50n");

  printf ("input year:");
  scanf ("%d", &tmp);
  year = InttoBCD (tmp);

  printf ("input month:");
  scanf ("%d", &tmp);
  month = InttoBCD (tmp);

  printf ("input day:");
  scanf ("%d", &tmp);
  day = InttoBCD (tmp);

  printf ("input hour:");
  scanf ("%d", &tmp);
  hour = InttoBCD (tmp);

  printf ("input minute:");
  scanf ("%d", &tmp);
  minute = InttoBCD (tmp);

  printf ("input second:");
  scanf ("%d", &tmp);
  second = InttoBCD (tmp);

  printf ("Date(hex):%x-%x-%x-%x-%x-%xn", year, month, day, hour, minute,
  second);
  /*
     retv = ioperm (0x70, 2, 1);
     if (retv == -1)
     {
     printf( "get error.n");
     return 1;
     }
   */
  /*
     outb_wxy(0x00, 0x70);
     outb_wxy(second, 0x71); //sec

     outb_wxy(0x02, 0x70);
     outb_wxy(minute, 0x71);  //min

     outb_wxy(0x04, 0x70);
     outb_wxy(hour, 0x71);  //hour

     outb_wxy(0x07, 0x70);
     outb_wxy(day, 0x71);  //day

     outb_wxy(0x08, 0x70);
     outb_wxy(month, 0x71);  //month

     outb_wxy(0x09, 0x70);
     outb_wxy(year, 0x71);  //year
   */
  /*
     outb(0x00, 0x70);
     outb(second, 0x71); //sec

     outb(0x02, 0x70);
     outb(minute, 0x71);  //min

     outb(0x04, 0x70);
     outb(hour, 0x71);  //hour

     outb(0x07, 0x70);
     outb(day, 0x71);  //day

     outb(0x08, 0x70);
     outb(month, 0x71);  //month

     outb(0x09, 0x70);
     outb(year, 0x71);  //year

     //get BIOS time
     outb (0x00, 0x70);
     tmp = inb(0x71);
     printf( "sec:%xn",tmp);

     outb (0x02, 0x70);
     tmp = inb(0x71);
     printf( "min:%xn", tmp);

     outb (0x04, 0x70);
     tmp = inb(0x71);
     printf( "hour:%xn", tmp);

     outb (0x07, 0x70);
     tmp = inb(0x71);
     printf( "day:%xn", tmp);

     outb (0x08, 0x70);
     tmp = inb(0x71);
     printf( "month:%xn", tmp);

     outb (0x09, 0x70);
     tmp = inb(0x71);
     printf( "year:%xn", tmp);

     retv = ioperm (0x70, 2, 0);
     if (retv == -1)
     {
     printf( "free error.n");
     return 1;
     } */
  return 0;
}

int
main ()
{
  set_time ();
  return 0;
}

void set_sys_time(char* tm)
{
// tm format "05/08/14 21:09:08"

char yy1[2],yy[4],mm[2],dd[2],hour[2],min[2],sec[2];
struct tm _tm;
time_t timep;
struct timeval tv;

memcpy(yy1,tm,2);
    sprintf(yy,"20%s",yy1);

memcpy(mm,tm+3,2);
memcpy(dd,tm+6,2);
memcpy(hour,tm+9,2);
memcpy(min,tm+12,2);
memcpy(sec,tm+15,2);

_tm.tm_sec  = atoi(sec);
_tm.tm_min  = atoi(min);
_tm.tm_hour = atoi(hour);
_tm.tm_mday = atoi(dd);
_tm.tm_mon  = atoi(mm) - 1;
_tm.tm_year = atoi(yy) - 1900;

    timep = mktime(&_tm);

tv.tv_sec  = timep;
tv.tv_usec = 0;
if(settimeofday (&tv, (struct timezone *) 0)