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.

SEE ALSO

       date(1), gettimeofday(2), time(2), ctime(3), gmtime(3), localtime(3)

COLOPHON

       This page is part of release 3.54 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/.