.SH DESCRIPTION
.BR stime ()
sets the system's idea of the time and date.
-Time, pointed
-to by \fIt\fP, is measured in seconds from 00:00:00 UTC January 1, 1970.
+The time, pointed
+to by \fIt\fP, is measured in seconds since the Epoch, 1970-01-01 00:00:00 +0000 (UTC).
.BR stime ()
may only be executed by the superuser.
.SH "RETURN VALUE"
.BI "time_t time(time_t *" t );
.SH DESCRIPTION
.BR time ()
-returns the time since the Epoch
-(00:00:00 UTC, January 1, 1970), measured in seconds.
+returns the time as the number of seconds since the Epoch,
+1970-01-01 00:00:00 +0000 (UTC).
If
.I t
specifies the new "last modification time" (\fImtime\fP).
Each of the elements of
.I times
-specifies a time in seconds and nanoseconds
-since the Epoch (00:00:00, 1 Jan 1970, UTC),
-in a structure of the following form:
+specifies a time as the the number of seconds and nanoseconds
+since the Epoch, 1970-01-01 00:00:00 +0000 (UTC).
+This information is conveyed in a structure of the following form:
.in +4n
.nf
functions all take
an argument of data type \fItime_t\fP which represents calendar time.
When interpreted as an absolute time value, it represents the number of
-seconds elapsed since 00:00:00 on January 1, 1970, Coordinated Universal
-Time (UTC).
+seconds elapsed since the Epoch, 1970-01-01 00:00:00 +0000 (UTC).
.PP
The
.BR asctime ()
function returns the number of seconds elapsed
between time \fItime1\fP and time \fItime0\fP, represented as a
.IR 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)).
+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).
.SH "CONFORMING TO"
SVr4, 4.3BSD, C89, C99.
.SH NOTES
.sp
.BI "int ftime(struct timeb *" tp );
.SH DESCRIPTION
-This function returns the current time, in seconds and milliseconds
-since the Epoch (00:00:00 UTC, 1 January 1970).
+This function returns the current time as seconds and milliseconds
+since the Epoch, 1970-01-01 00:00:00 +0000 (UTC).
The time is returned in
.IR tp ,
which is declared as follows:
char *sp_namp; /* Login name */
char *sp_pwdp; /* Encrypted password */
long sp_lstchg; /* Date of last change (measured
- in days since 1 Jan 1970) */
+ in days since 1970-01-01 00:00:00 +0000 (UTC)) */
long sp_min; /* Min # of days between changes */
long sp_max; /* Max # of days between changes */
long sp_warn; /* # of days before password expires
long sp_inact; /* # of days after password expires
until account is disabled */
long sp_expire; /* Date when account expires (measured
- in days since 1 Jan 1970) */
+ in days since 1970-01-01 00:00:00 +0000 (UTC)) */
unsigned long sp_flag; /* Reserved */
};
.fi
points to a structure which specifies a ceiling on the time for which
the call will block.
This ceiling is an absolute timeout in seconds and nanoseconds
-since the Epoch (midnight on the morning of 1 January 1970),
+since the Epoch, 1970-01-01 00:00:00 +0000 (UTC), and it is
specified in the following structure:
.sp
.in +4n
points to a structure which specifies a ceiling on the time for which
the call will block.
This ceiling is an absolute timeout in seconds and nanoseconds
-since the Epoch (midnight on the morning of 1 January 1970),
+since the Epoch, 1970-01-01 00:00:00 +0000 (UTC), and it is
specified in the following structure:
.sp
.in +4n
The Time Server Protocol gives the time in seconds since
00:00:00 UTC, 1 Jan 1900,
and this function subtracts the appropriate constant in order to
-convert the result to seconds since
-00:00:00 UTC, 1 Jan 1970, the Unix Epoch.
+convert the result to seconds since the Epoch,
+1970-01-01 00:00:00 +0000 (UTC).
.LP
When
.I timeout
The
.I abs_timeout
argument points to a structure that specifies an absolute timeout
-in seconds and nanoseconds since the Epoch (00:00:00, 1 January 1970).
+in seconds and nanoseconds since the Epoch, 1970-01-01 00:00:00 +0000 (UTC).
This structure is defined as follows:
.nf
below.
.TP
.B %s
-The number of seconds since the Epoch, that is, since 1970-01-01
-00:00:00 UTC. (TZ)
+The number of seconds since the Epoch, 1970-01-01 00:00:00 +0000 (UTC). (TZ)
.TP
.B %S
The second as a decimal number (range 00 to 60).
Finally
.TP
.B %s
-The number of seconds since the Epoch,
-that is, since 1970-01-01 00:00:00 UTC.
+The number of seconds since the Epoch, 1970-01-01 00:00:00 +0000 (UTC).
Leap seconds are not counted unless leap second support is available.
.LP
The glibc implementation does not require whitespace between
.I timeval
structure pointed to by
.IR tvp ,
-so that it represents the time at midnight
-on the morning of 1 January 1970 (the Epoch).
+so that it represents the Epoch: 1970-01-01 00:00:00 +0000 (UTC).
.BR timerisset ()
returns true (nonzero) if either field of the
.BR time (2),
as well as setting timestamps on files, etc.
The system clock reports seconds and microseconds since a start point,
-defined to be the POSIX Epoch: Jan 1, 1970, 0:00 UTC.
+defined to be the POSIX Epoch: 1970-01-01 00:00:00 +0000 (UTC).
(One common implementation counts timer interrupts, once
per "jiffy", at a frequency of 100, 250, or 1000 Hz.)
That is, it is supposed to report wall clock time, which RTCs also do.
number of signal causing dump
.TP
%t
-time of dump, expressed as seconds since the Epoch (00:00h, 1\ Jan 1970, UTC)
+time of dump, expressed as seconds since the Epoch, 1970-01-01 00:00:00 +0000 (UTC)
.TP
%h
hostname (same as \fInodename\fP returned by \fBuname\fP(2))
The number of context switches that the system underwent.
.TP
\fIbtime 769041601\fP
-boot time, in seconds since the Epoch (January 1, 1970).
+boot time, in seconds since the Epoch, 1970-01-01 00:00:00 +0000 (UTC).
.TP
\fIprocesses 86031\fP
Number of forks since boot.
.PP
The 64-bit timestamp returned by
.B ICMP_TIMESTAMP
-is in milliseconds since January 1, 1970.
+is in milliseconds since the Epoch, 1970-01-01 00:00:00 +0000 (UTC).
.PP
Linux ICMP internally uses a raw socket to send ICMPs.
This raw socket may appear in
.SS "The Epoch"
Unix systems represent time in seconds since the
.IR Epoch ,
-which is defined as 0:00:00 UTC on the morning of 1 January 1970.
+1970-01-01 00:00:00 +0000 (UTC).
A program can determine the
.I "calendar time"