What is tm in C?
struct tm is a structure defined in the time.h header file in C language. Each of the member objects of struct tm contains the time and date stored on a machine.
Below is a table that outlines what each member of the struct holds. The Daylight Saving Time flag is positive if it is daylight saving time, negative if it is unknown, and 0 if it is not daylight saving time. All the members are of type int.
Members of Struct
Member | |
tm_sec | seconds passed since last minute |
tm_min | minutes passed since hour |
tm_hour | hours passed since midnight |
tm_mday | day of the month |
tm_mon | months passed since January |
tm_year | year passed since 1900 |
tm_wday | days since Sunday |
tm_yday | days since first day of the year |
tm_isdst | Daylight Saving Time Flag |
Example
The code below illustrates how you can use struct tm to print the calendar time and date. The values for the members of the struct are set to Mon Feb 1 01:01:01 1901 using the (.) operator.
#include<stdio.h>#include<time.h>int main() {struct tm value;value.tm_sec=1;value.tm_min=1;value.tm_hour=1;value.tm_mday=1;value.tm_mon=1;value.tm_year=1;value.tm_hour=1;value.tm_wday=1;value.tm_yday=1;printf("Time and date: %s", asctime(&value));return 0;}
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