Linux C Language Acquisition system time information

For example, get the current year:
/* Get current system time temporarily not used
int iyear = 0;
int sysyear = 0;
time_t now;
struct TM *timenow;
Time (&now);
TimeNow = LocalTime (&now);
Sysyear = timenow->tm_year+1900;
*/
How to get system time under Linux
You can use the LocalTime function to get the numeric value of the day and the month respectively.

The implementation method of C language for acquiring system time under Linux:

1. You can use the LocalTime function to obtain the numeric value of the day and the month respectively.

Header files for #include <time.h>//C language

#include <stdio.h>//C-language I/O

void Main ()

{

time_t now; Instantiate the time_t structure

struct TM *timenow; Instantiate a TM structure pointer

Time (&now);

The time function reads the current (international standard Time is not Beijing time) and then passes the value to now

TimeNow = LocalTime (&now);

The LocalTime function converts the time that you have obtained from hours to the time in your computer (the region you set up)

printf ("Local time is%s/n", Asctime (TimeNow));

In the previous sentence, the Asctime function converts the time into a character and outputs it through the printf () function.

}

Note: time_t is a struct that is defined in the time.h. The prototype of the TM structure is as follows:

struct TM

{

int Tm_sec;//seconds 0-61

int Tm_min;//minutes 1-59

int tm_hour;//hours 0-23

int tm_mday;//day of the month 1-31

int tm_mon;//months since Jan 0-11

int Tm_year;//years from 1900

int tm_wday;//days since Sunday, 0-6

int tm_yday;//days since Jan 1, 0-365

int Tm_isdst;//daylight Saving Time indicator

};

2. Linux provides gettimeofday () for certain requirements that require high accuracy.

#include <stdio.h>

#include <stdlib.h>

#include <sys/time.h>

int main (int argc, char **argv)

{

struct Timeval Start,stop,diff;

Gettimeofday (&start,0);

Do what you have to do ...

Gettimeofday (&stop,0);

Tim_subtract (&diff,&start,&stop);

printf ("Total elapsed:%d milliseconds/n", diff.tv_usec);

}

int tim_subtract (struct timeval *result, struct timeval *x, struct timeval *y)

{

int nsec;

if (X->tv_sec > Y->tv_sec)

return-1;

if ((x->tv_sec==y->tv_sec) && (x->tv_usec>y->tv_usec))

return-1;

Result->tv_sec = (y->tv_sec-x->tv_sec);

Result->tv_usec = (y->tv_usec-x->tv_usec);

if (result->tv_usec<0)

{

result->tv_sec--;

result->tv_usec+=1000000;

}

return 0;

}

Linux C Language Acquisition system time information