difftime

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.  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 5.11 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/.



GNU                                2021-03-22                        DIFFTIME(3)