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).

ATTRIBUTES

   For  an  explanation  of  the  terms  used   in   this   section,   see
   attributes(7).

   
   Interface   Attribute      Value   
   
   difftime()  Thread safety  MT-Safe 
   

CONFORMING TO

   POSIX.1-2001, POSIX.1-2008, C89, C99, SVr4, 4.3BSD.

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

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