DIFFTIME(3)

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. Each of the times is specified in calendar time, which means its value is a measurement (in seconds) relative to the Epoch, 1970-01-01 00:00:00 +0000 (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
This page is part of release 3.41 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.