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

This page is part of release 4.07 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man−pages/.


  Copyright 1993 David Metcalfe (davidprism.demon.co.uk)

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References consulted:
    Linux libc source code
    Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
    386BSD man pages
Modified Sat Jul 24 19:48:17 1993 by Rik Faith (faithcs.unc.edu)