#include <time.h> double difftime(time_t time2, time_t time1);
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).
difftime
returns the difference between the two times in seconds.
difftime
is implemented as a macro. If its arguments are not of
type time_t
, the results are not meaningful.
#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); }
time
Copyright (c) 1998 SAS Institute Inc. Cary, NC, USA. All rights reserved.