'\"
'\" Copyright (c) 1992-1995 Karl Lehenbauer and Mark Diekhans.
'\" Copyright (c) 1995-1997 Sun Microsystems, Inc.
'\" Copyright (c) 1998-1999 Scriptics Corporation
'\" Copyright (c) 2002 ActiveState Corporation
'\"
'\" This documentation is derived from the time and date facilities of
'\" TclX, by Mark Diekhans and Karl Lehenbauer.
'\" 
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\" 
'\" RCS: @(#) $Id: clock.n,v 1.11.2.6 2004/12/13 15:52:21 kennykb Exp $
'\" 
.so man.macros
.TH clock n 8.4 Tcl "Tcl Built-In Commands"
.BS
'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
clock \- Obtain and manipulate time
.SH SYNOPSIS
\fBclock \fIoption\fR ?\fIarg arg ...\fR?
.BE

.SH DESCRIPTION
.PP
This command performs one of several operations that may obtain
or manipulate strings or values that represent some notion of
time.  The \fIoption\fR argument determines what action is carried
out by the command.  The legal \fIoptions\fR (which may be
abbreviated) are:
.VS 8.3
.TP
\fBclock clicks\fR ?\fB\-milliseconds\fR?
Return a high-resolution time value as a system-dependent integer
value.  The unit of the value is system-dependent but should be the
highest resolution clock available on the system such as a CPU cycle
counter. If \fB\-milliseconds\fR is specified, then the value is
guaranteed to be of millisecond granularity.
This value should only be used for the relative measurement
of elapsed time.
.VE 8.3
.TP
\fBclock format \fIclockValue\fR ?\fB\-format \fIstring\fR? ?\fB\-gmt \fIboolean\fR?
Converts an integer time value, typically returned by
\fBclock seconds\fR, \fBclock scan\fR, or the \fBatime\fR or \fBmtime\fR
options of the \fBfile\fR command, to human-readable
form.  If the \fB\-format\fR argument is present the next argument is a
string that describes how the date and time are to be formatted.
Field descriptors consist of a \fB%\fR followed by a field
descriptor character.  All other characters are copied into the result.
Valid field descriptors are:
.RS
.IP \fB%%\fR
Insert a %.
.IP \fB%a\fR
Abbreviated weekday name (Mon, Tue, etc.).
.IP \fB%A\fR
Full weekday name (Monday, Tuesday, etc.).
.IP \fB%b\fR
Abbreviated month name (Jan, Feb, etc.).
.IP \fB%B\fR
Full month name.
.VS 8.4
.IP \fB%c\fR
Locale specific date and time.  The format for date and time
in the default "C" locale on Unix/Mac is "%a %b %d %H:%M:%S %Y".
On Windows, this value is the locale specific long date and time, as
specified in the Regional Options control panel settings.
.IP \fB%C\fR
First two digits of the four-digit year (19 or 20).
.VE 8.4
.IP \fB%d\fR
Day of month (01 - 31).
.VS 8.4
'\" Since the inclusion of compat/strftime.c, %D, %e, %h should work on all
'\" platforms.
.IP \fB%D\fR
Date as %m/%d/%y.
.IP \fB%e\fR
Day of month (1 - 31), no leading zeros.
.IP \fB%g\fR
The ISO8601 year number corresponding to the ISO8601 week (%V), expressed
as a two-digit year-of-the-century, with leading zero if necessary.
.IP \fB%G\fR
The ISO8601 year number corresponding to the ISO8601 week (%V), expressed
as a four-digit number.
.IP \fB%h\fR
Abbreviated month name.
.VE 8.4
.IP \fB%H\fR
Hour in 24-hour format (00 - 23).
.VS 8.4
.IP \fB%I\fR
Hour in 12-hour format (01 - 12).
.VE 8.4
.IP \fB%j\fR
Day of year (001 - 366).
.VS 8.4
.IP \fB%k\fR
Hour in 24-hour format, without leading zeros (0 - 23).
.IP \fB%l\fR
Hour in 12-hour format, without leading zeros (1 - 12).
.VE 8.4
.IP \fB%m\fR
Month number (01 - 12).
.IP \fB%M\fR
Minute (00 - 59).
.VS 8.4
.IP \fB%n\fR
Insert a newline.
.VE 8.4