DIFFTIME(3)                                         Linux Programmer's Manual                                        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 3.25 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/.



GNU                                                        2010-02-25                                                DIFFTIME(3)