linux时间转换函数

• 一.linux
• 二.python

  一.linux

  cat > linux_time.c <<-'EOF'
  #define _GNU_SOURCE
  #include 
  #include 
  #include 
  #include 
  #include 
  int main(int argc,char*argv[])
  {
  	char date_string[128]={0};
  	
  	// 1.获取当前系统时间,精确到毫秒 方法1 
  	{
  		struct timeb tTimeB;
  		ftime(&tTimeB);
  		struct tm *tm = localtime(&tTimeB.time);			
  		sprintf(date_string,"%04d-%02d-%02d %02d:%02d:%02d.%03d",
  				tm->tm_year + 1900,tm->tm_mon + 1, tm->tm_mday, 
  				tm->tm_hour, tm->tm_min, tm->tm_sec,tTimeB.millitm);
  		printf("%s\n",date_string);
  	}
  	
  	// 2.获取当前系统时间,精确到毫秒 方法2
  	{
  		struct timespec ts;
  		char buffer[30];
  		clock_gettime(CLOCK_REALTIME, &ts);
  		struct tm *tm = localtime(&ts.tv_sec);
  		strftime(buffer, sizeof(buffer), "%Y-%m-%d %H:%M:%S", tm);
  		printf("%s.%03d\n", buffer, ts.tv_nsec/1000/1000);
  	}
  	// 3.字符串转时间
  	{
  		struct tm tm;
  		memset(&tm,0,sizeof(tm)); //如果不清空mktime偶尔会失败
  		long milliseconds;
  		char*end_ptr  = strptime(date_string, "%Y-%m-%d %H:%M:%S", &tm);
  		if (end_ptr  == NULL) {
  			fprintf(stderr, "Failed to parse date string：%s\n",date_string);
  			return 1;
  		}
  		if (*end_ptr  == '.') {
  			milliseconds = strtol(end_ptr  + 1, NULL, 10);
  		} else {
  			milliseconds = 0;
  		}
  		
  		time_t t = mktime(&tm);
  		if (t == -1) {
  			fprintf(stderr, "Failed to convert tm to time_t:%s\n",date_string,t);
  			return 1;
  		}
  		
  		struct timespec ts;
  		ts.tv_sec = t;
  		ts.tv_nsec = milliseconds * 1000000L;
  		printf("%04d-%02d-%02d %02d:%02d:%02d.%03d\n",
  				tm.tm_year + 1900,tm.tm_mon + 1,tm.tm_mday,
  				tm.tm_hour,tm.tm_min,tm.tm_sec,milliseconds);
  	}
  }
  EOF
  gcc -o linux_time linux_time.c
  ./linux_time
  

  二.python

  cat > test_time.py <<-'EOF'
  from datetime import datetime
  # 1.获取当前系统时间
  now = datetime.now()
  # 2.格式化为字符串
  time_str=now.strftime("%Y-%m-%d %H:%M:%S.%f")
  print(time_str)
  # 3.字符串转时间
  time=datetime.strptime(time_str, "%Y-%m-%d %H:%M:%S.%f")
  # 4.时间转字符串输出
  print(time.strftime("%Y-%m-%d %H:%M:%S.%f"))
  EOF
  python3 test_time.py