LINUX系统编程之日历时间

LINUX中时间有两种：
1）日历时间
2）进程时间
日历时间顾名思义即用来获取日历；
主要涉及到的函数有：
time(time_t*);
stime(time_t*);
tm* gmtime(time_t*);
tm* localtime(time_t*);
char *strftime(tm*);
char *asctime(tm*);
time_t* mktime(tm*);
数据结构如下：
time_t
struct tm{
  int tm_sec;
  int tm_min;
  int tm_hour;
  int tm_mday;
  int tm_wday;
  int tm_yday;
  int tm_year;
  int tm_isdst;
}
转换关系如下图：
示例代码如下：
struct utsname aname;
int a=uname(&aname);
cout << a;
cout << endl;
cout << aname.sysname<< endl;
cout << aname.machine<< endl;
cout << aname.release<< endl;
cout << aname.version<<endl;
cout << aname.nodename<< endl;


time_t time1;
time_t time2;
time2=time(&time1);
cout << time1 << endl;
cout << time2 << endl;
struct tm *tm1;
tm1=localtime(&time1);
cout << tm1->tm_sec<<endl;
cout << tm1->tm_min<<endl;
cout << tm1->tm_hour<<endl;
cout << tm1->tm_mday<<endl;
cout << tm1->tm_mon<<endl;
cout << tm1->tm_year<<endl;
cout << tm1->tm_wday<<endl;
cout << tm1->tm_yday<<endl;
char *css;
css=asctime(tm1);
cout << css;
size_t size=strftime(css,100,"%Y-%m-%d %H-%M-%S %w",tm1);
cout << size << ":"<<css;