# [OS X TeX] datetime package

Bruno Voisin bvoisin at mac.com
Sat Mar 17 10:19:53 CET 2007

Le 16 mars 07 à 17:19, Salvatore Enrico Indiogine a écrit :

> I would like to modify the format of the date produced by \today from
>
> month day, year
>
> to the European format
>
> day month year
>
> I added \usepackage{datetime} to my preamble and received the
> following message:
>
> LaTeX Error: File datetime.sty' not found
>
> So, I guess I have something missing in my TeX installation.  I am
> still a TeX newbie so I am at a low here.

Just two remarks, in addition to the other answers you've got already:

- The datetime package isn't included in gwTeX, installed by i-
Installer, which I suppose is the TeX distribution you've got.
However, it is included in TeXLive-2007, as installed by the MacTeX
installer available from <http://www.tug.org/mactex>. Beware: huge

- If you skip the datetime package and finally decide to do things
manually, and if you want to go "by the book", there are actually two
commands in LaTeX, \date and \today:

-- \today is a command taking no argument, and returning the current
date at the time your .tex document is typeset.

-- \date is a command taking one argument, and defining the date that
is used in title pages, in headings, in letters, etc.

LaTeX initializes \date to \today (namely latex.ltx sets \date
{\today}), but you can change this to anything of your liking. For
example, if you want a report to bear the date it was actually
completed, say 17 March 2007, just write:

\date{17~March 2007}

Without this redefinition, imagine you lose the .pdf file for your
report and decide to re-typeset the .tex input later on 27 July 2007,
say, then your report will have the date returned by \today in its
title page, namely 27 July 2007, instead of the original date of its
completion, namely 17 March 2007.

So, if you want to do things consistently, for changing the format of
all dates generated automatically by LaTeX, you need to redefine
\today, using either the babel package (which adapts date formats to
the assumed standards of each language) or doing the redefinition
yourself manually. The LaTeX default is:

\def\today{\ifcase\month\or
January\or February\or March\or April\or May\or June\or
July\or August\or September\or October\or November\or December\fi
\space\number\day, \number\year}

which is more-or-less self-explanatory, and this can be easily enough
redefined to the European format using:

\renewcommand{\today}{\number\day\space\ifcase\month\or
January\or February\or March\or April\or May\or June\or
July\or August\or September\or October\or November\or December\fi
\space\number\year}

And for adjusting a given date yourself, just use \date.

Hope this helps,

Bruno Voisin
------------------------- Helpful Info -------------------------
Mac-TeX Website: http://www.esm.psu.edu/mac-tex/
TeX FAQ: http://www.tex.ac.uk/faq
List Archive: http://tug.org/pipermail/macostex-archives/
List Reminders & Etiquette: http://www.esm.psu.edu/mac-tex/list/

`