Originální popis anglicky:
difftime - calculate time difference
Návod, kniha: Linux Programmer's Manual
#include <time.h>
double difftime(time_t time1, time_t time0);
The
difftime() function returns the number of seconds elapsed between
time
time1 and time
time0, represented as a double. The two
times are specified in calendar time, which represents the time elapsed since
the Epoch (00:00:00 on January 1, 1970, Coordinated Universal Time (UTC)).
SVID 3, BSD 4.3, ISO 9899
This function is required by ANSI C. On a POSIX system, time_t is an arithmetic
type, and one could just define
#define difftime(t1,t0) (double)(t1 - t0)
when the possible overflow in the subtraction is not a concern.
date(1),
gettimeofday(2),
time(2),
ctime(3),
gmtime(3),
localtime(3)
