difftime

difftime

Compute the Difference of Two Times

Portability: ISO/ANSI C conforming

SYNOPSIS
DESCRIPTION
RETURN VALUE
CAUTION
EXAMPLE
RELATED FUNCTIONS
SEE ALSO

SYNOPSIS

#include <time.h>

double difftime(time_t time2, time_t time1);

DESCRIPTION

difftime computes the difference time2 - time1 in seconds, where time2 and time1 are values of type time_t (such as those returned by the time function).

RETURN VALUE

difftime returns the difference between the two times in seconds.

CAUTION

difftime is implemented as a macro. If its arguments are not of type time_t , the results are not meaningful.

EXAMPLE

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

main()
{
   double x;
   time_t last_written;          /* time data last written */
                                 /* time(&last_written);   */

      /* if data are more than 1 week old                  */
   if ((x = difftime(time(NULL), last_written)) > 7 * 86400)
      puts("Warning: These data are obsolete");
   else printf("Data was last accessed %lf seconds ago.\n", x);
}

RELATED FUNCTIONS

time

SEE ALSO

Timing Functions

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