difftime (3)

#include <time.h>

double difftime(time_t time1, time_t time0);

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).

Multithreading (see pthreads(7))

The difftime() function is thread-safe.

SVr4, 4.3BSD, C89, C99.

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.

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

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