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. 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 doesnt work directly.
SEE ALSO date(1), gettimeofday(2), time(2), ctime(3), gmtime(3), localtime(3)
COLOPHON This page is part of release 3.22 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 2002-02-28 DIFFTIME(3)