%% LtabTest.tex---Uwe L"uck---spacing error in longtable.sty. 
%% 2004/08/23. %%% First: 2002/12/08. 
%% tools/3485, cf. tools/3180, Sebastian Rahtz 2000/03/05. 
\documentclass{article} 
\usepackage{longtable}
% \usepackage{ltabptch}
% \nofiles 
\begin{document}
% A 

\noindent 
% D\hfil\break 
B % \strut % \vrule depth 9.9pt 
% \par 
% \begin{center} 
%% center around longtable produces spurious line below indeed! 
\begin{longtable}[l]{l}
\smash{\vrule height 20.4pt depth 15.6pt }% bigskip added. 
H % \vrule depth 8.8 pt 
% \\ 
\endhead 
% \begin{tabular}{l}
\smash{\vrule height 20.4pt depth 15.6pt }% strut + bigskip. 
T % \vrule depth % 15.6pt 
% 7.7pt %%% \vrule height 8.399pt depth 3.6pt 
\\ 
\end{longtable} 
% \end{tabular}
% \end{center}
% \par 
 \edef\testhold{\the\prevdepth}\typeout{\prevdepth= \testhold}% TEST 
\noindent
C

\tracingonline=1 
\showboxbreadth=20
\showboxdepth=3
\showlists 

\setbox0\hbox{Aq}
\typeout{ht = \the\ht0; dp = \the\dp0}

\end{document}

