%%
%% The LaTeX Companion, 3ed
%%
%% Example B-4-1 on page II-769 in "Displaying command definitions and register values".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{159.0pt}
%StartShownPreambleCommands
\newcommand\xvec[1]{\ensuremath{x_1,\ldots,x_{#1}}}
%StopShownPreambleCommands

\begin{document}
\ttfamily\small    % use smaller typewriter
\raggedright
\meaning\xvec   \par \the\parskip\par
\the\topmargin  \par \the\topsep \par
footnote=\the\value{footnote}
\end{document}