DIFFTIME
Section: Linux Programmer's Manual (3)
Updated: 2002-02-28
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NAME
difftime - calculate time difference
SYNOPSIS
#include <time.h>
double difftime(time_t time1, time_t time0);
DESCRIPTION
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)).
CONFORMING TO
SVr4, 4.3BSD, C89, C99.
NOTES
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.
On other systems, the data type
time_t
might use some other encoding
where subtraction doesn't work directly.
SEE ALSO
date(1),
gettimeofday(2),
time(2),
ctime(3),
gmtime(3),
localtime(3)
COLOPHON
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