C library functions - gmtime ()

C standard library - <time.h>

description

C library functionsstruct tm * gmtime (const time_t * timer) uses the value of the timertm structure to fill and use Coordinated Universal Time (UTC) is also known as Greenwich Mean Time (GMT) represented.

statement

The following is a statement gmtime () function.

struct tm *gmtime(const time_t *timer)

parameter

• timeptr - This is a pointer to a pointer showing a time_t calendar time value.

return value

This function returns a pointer to tm structure, the structure is filled with time information. Here are the details timeptr structure:

struct tm {
   int tm_sec;         /* 秒，范围从 0 到 59				*/
   int tm_min;         /* 分，范围从 0 到 59				*/
   int tm_hour;        /* 小时，范围从 0 到 23				*/
   int tm_mday;        /* 一月中的第几天，范围从 1 到 31	                */
   int tm_mon;         /* 月份，范围从 0 到 11				*/
   int tm_year;        /* 自 1900 起的年数				*/
   int tm_wday;        /* 一周中的第几天，范围从 0 到 6		        */
   int tm_yday;        /* 一年中的第几天，范围从 0 到 365	                */
   int tm_isdst;       /* 夏令时						*/	
};

Examples

The following example demonstrates gmtime () function is used.

#include <stdio.h>
#include <time.h>

#define BST (+1)
#define CCT (+8)

int main ()
{

   time_t rawtime;
   struct tm *info;

   time(&rawtime);
   /* 获取 GMT 时间 */
   info = gmtime(&rawtime );
   
   printf("当前的世界时钟：\n");
   printf("伦敦：%2d:%02d\n", (info->tm_hour+BST)%24, info->tm_min);
   printf("中国：%2d:%02d\n", (info->tm_hour+CCT)%24, info->tm_min);

   return(0);
}

Let's compile and run the above program, which will result in the following:

当前的世界时钟：
伦敦：14:10
中国：21:10

C standard library - <time.h>