时间标签（timestamp）的格式为RFC3339格式。
strptime 和strptime函数#include <stdio.h> /* puts, printf */#include <time.h> /* time_t, struct tm, time, localtime */#include <string>using namespace std;int main (){ time_t rawtime; struct tm * timeinfo;char buffer [80]; time (&rawtime); timeinfo = localtime (&rawtime); int length= strftime (buffer,80,"%Y-%m-%dT%H:%M:%SZn",timeinfo); printf ("timestamp: %.*s",length,buffer); return 0;}
strptime 函数将字符串转换成 tm 结构
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <time.h>using namespace std; int main(void) { struct tm *timeinfo; char buffer[80]; memset( timeinfo, 0, sizeof(struct tm)); strptime("2001-11-12 18:31:01", "%Y-%m-%d %H:%M:%S", timeinfo); int length= strftime (buffer,80,"%Y-%m-%dT%H:%M:%SZn",timeinfo); printf ("timestamp: %.*s",length,buffer); exit(EXIT_SUCCESS); } localtime 和mktime 函数mktime 将tm 结构转换成 time_t
localtime 将time_t 转换成 tm结构时间
gmtime 函数 Convert time_t to tm as UTC time