C语言时间函数
1、
time函数
头文件：
time.h
函数定义：
time_t time (time_t *t)
说明：返回从
1970年
1月
1日的
UTC时间从
0时
0分
0妙算起到现在所经过的秒数。
#include<stdio.h>
#include<time.h>
int main(){
time_t timep;
long seconds = time(&timep);
printf("%ld\n",seconds);
printf("%ld\n",timep);
return 0;
}
#include<time.h>
int main(){
time_t timep;
long seconds = time(&timep);
printf("%ld\n",seconds);
printf("%ld\n",timep);
return 0;
}
输出：
1302079744
1302079744
2、
ctime函数
定义：char *ctime(const time_t *timep);
说明：将参数所指的time_t
结构中的信息转换成真实世界的时间日期表示方法，然后将结果以字符串形式返回。这个是本地时间。
#include <stdio.h>
#include<time.h>
int main(void) {
time_t timep;
time(&timep);
printf("%s\n",ctime(&timep));
return 0;
}
输出：Wed Apr 6 16:53:35 2011
#include<time.h>
int main(void) {
time_t timep;
time(&timep);
printf("%s\n",ctime(&timep));
return 0;
}
输出：Wed Apr 6 16:53:35 2011
3、
gettime函数
定义：
struct tm *gmtime(const time_t *timep);
说明：将参数timep
所指的time_t
结构中的信息转换成真实世界所使用的时间日期表示方法，然后将结果由结构tm
返回。此函数返回的时间日期未经时区转换，而是UTC
时间。struct tm
结构的定：
struct tm{
int tm_sec;/*
秒数*/
int tm_min; /*
分钟*/
int tm_hour;/*
小时*/
int tm_mday;/*
日期*/
int tm_mon; /*
月份*/
int tm_year; /*
从1990
年算起至今的年数*/
int tm_wday; /*
星期*/
int tm_yday; /*
从今年1
月1
日算起至今的天数*/
int tm_isdst; /*
日光节约时间的旗标*/
};
#include <stdio.h>
#include<time.h>
int main(void) {
char *wday[] = {"Sun","Mon","Tue","Wed","Thu","Fri","Sat"};
time_t timep;
struct tm *p;
time(&timep);
p = gmtime(&timep);
printf("%d/%d/%d ",(1900+p->tm_year),(1+p->tm_mon),p->tm_mday);
printf("%s %d:%d:%d\n",wday[p->tm_wday],p->tm_hour,p->tm_min,p->tm_sec);
return 0;
}
输出：2011/4/6 Wed 8:59:0
#include<time.h>
int main(void) {
char *wday[] = {"Sun","Mon","Tue","Wed","Thu","Fri","Sat"};
time_t timep;
struct tm *p;
time(&timep);
p = gmtime(&timep);
printf("%d/%d/%d ",(1900+p->tm_year),(1+p->tm_mon),p->tm_mday);
printf("%s %d:%d:%d\n",wday[p->tm_wday],p->tm_hour,p->tm_min,p->tm_sec);
return 0;
}
输出：2011/4/6 Wed 8:59:0
4、
asctime函数
定义：
char *asctime(const struct tm *timeptr);
说明：将参数
timeptr所指的
struct tm结构中的信息转换成真实时间所使用的时间日期表示方法，结果以字符串形态返回。与
ctime()函数不同之处在于传入的参数是不同的结构。注意返回的也是
UTC时间。
#include <stdio.h>
#include <stdlib.h>
#include<time.h>
int main(void) {
time_t timep;
time(&timep);
printf("%s\n",asctime(gmtime(&timep)));
return EXIT_SUCCESS;
}
输出：Wed Apr 6 09:00:39 2011
#include <stdlib.h>
#include<time.h>
int main(void) {
time_t timep;
time(&timep);
printf("%s\n",asctime(gmtime(&timep)));
return EXIT_SUCCESS;
}
输出：Wed Apr 6 09:00:39 2011
5
、 localhost
函数
struct tm *localhost(const time_t *timep);
取得当地目前的时间和日期
#include <stdio.h>
#include <stdlib.h>
#include<time.h>
int main(void) {
char *wday[] = {"Sun","Mon","Tue","Wed","Thu","Fri","Sat"};
time_t timep;
struct tm *p;
time(&timep);
p = localtime(&timep);
printf("%d/%d/%d ",(1900+p->tm_year),(1+p->tm_mon),p->tm_mday);
printf("%s %d:%d:%d\n",wday[p->tm_wday],p->tm_hour,p->tm_min,p->tm_sec);
return EXIT_SUCCESS;
}
输出：2011/4/6 Wed 17:3:0
#include <stdlib.h>
#include<time.h>
int main(void) {
char *wday[] = {"Sun","Mon","Tue","Wed","Thu","Fri","Sat"};
time_t timep;
struct tm *p;
time(&timep);
p = localtime(&timep);
printf("%d/%d/%d ",(1900+p->tm_year),(1+p->tm_mon),p->tm_mday);
printf("%s %d:%d:%d\n",wday[p->tm_wday],p->tm_hour,p->tm_min,p->tm_sec);
return EXIT_SUCCESS;
}
输出：2011/4/6 Wed 17:3:0
6
、mktime
函数
定义：time_t mktime(struct tm *timeptr);
说明：用来将参数timeptr
所指的tm
结构数据转换成从1970
年1
月1
日的UTC
时间从0
时0
分0
妙算起到现在所经过的秒数。
#include <stdio.h>
#include <stdlib.h>
#include<time.h>
int main(void) {
time_t timep;
struct tm *p;
time(&timep);
printf("time():%ld\n",timep);
p = localtime(&timep);
timep = mktime(p);
printf("time()->localtime()->mktime():%ld\n",timep);
return EXIT_SUCCESS;
}
输出：time():1302080789
time()->localtime()->mktime():1302080789
#include <stdlib.h>
#include<time.h>
int main(void) {
time_t timep;
struct tm *p;
time(&timep);
printf("time():%ld\n",timep);
p = localtime(&timep);
timep = mktime(p);
printf("time()->localtime()->mktime():%ld\n",timep);
return EXIT_SUCCESS;
}
输出：time():1302080789
time()->localtime()->mktime():1302080789
7
、 gettimeofday
函数
定义：int gettimeofday(struct timeval *tv,struct timezone *tz);
说明：把目前的时间由tv
所指的结构返回，当地时区信息则放到有tz
所指的结构中，
struct timeval{
long tv_sec; /*
秒*/
long tv_usec; /*
微秒*/
};
struct timezone{
int tz_minuteswest; /*
和greenwich
时间差了多少分钟*/
int tz_dsttime; /*
日光节约时间的状态*/
}
#include <stdio.h>
#include <stdlib.h>
#include<time.h>
#include<sys/time.h>
int main(void) {
struct timeval tv;
struct timezone tz;
gettimeofday(&tv,&tz);
printf("tv_sec :%d\n",tv.tv_sec);
printf("tv_usec: %d\n",tv.tv_usec);
printf("tz_minuteswest:%d\n",tz.tz_minuteswest);
printf("tz_dsttime:%d\n",tz.tz_dsttime);
return EXIT_SUCCESS;
}
输出：tv_sec :1302081017
tv_usec: 532325
tz_minuteswest:-480
tz_dsttime:0
#include <stdlib.h>
#include<time.h>
#include<sys/time.h>
int main(void) {
struct timeval tv;
struct timezone tz;
gettimeofday(&tv,&tz);
printf("tv_sec :%d\n",tv.tv_sec);
printf("tv_usec: %d\n",tv.tv_usec);
printf("tz_minuteswest:%d\n",tz.tz_minuteswest);
printf("tz_dsttime:%d\n",tz.tz_dsttime);
return EXIT_SUCCESS;
}
输出：tv_sec :1302081017
tv_usec: 532325
tz_minuteswest:-480
tz_dsttime:0