Three different captions: longtable

Question

My problem is that I have tables that are three pages long. Thus, I would like to have three different captions when using the longtable package.

The similar question How to use a longtable with only one entry in the list of tables does not solve my problem. As far as I know this is how we could use longtable regarded this matter:

\caption{Example of longtable}
\endfirsthead
\caption[]{Continued}
\endhead

However, if the table occupies three pages, so that's how the captions are:

Table 2.1 - Example of longtable (page 1)

Table 2.1 - Continued (page 2)

Table 2.1 - Continued (page 3)

In other words, I can not get different captions for the second and third pages. That's what I want and that's the problem.

Answer 1

longtable has two settings for the headers of the table: \endfirsthead and \endhead. The contents of \endfirsthead will be saved in the save box \LT@firsthead and the contents of \endhead in \LT@head. If the box \LT@firsthead is empty, longtable uses the contents of \LT@head. The same procedure will be used for the footer. In the same way I defined a \endsecondhead

\def\endsecondhead{\LT@end@hd@ft\LT@secondhead}

To use this command I have to define a new save box which will be set only on the second page.

\newbox\LT@secondhead

To make sure that only on the second page this box will be used I have to manipulate the output of longtable. Therefore I use a simple \ifvoid clause.

\ifvoid\LT@secondhead
   \copy\LT@head\nobreak
\else
   \box\LT@secondhead\nobreak
\fi

\ifvoid tests whether the save box \LT@secondhead is empty or not. If you set a second head, the box will be printed by \box. This command prints the box and clears the box. So on the next page the test above is true. In this way you make sure that when no second head is defined the \endhead will be used.

To allow for more than three different headings you must define new save boxes and extend the test.

\documentclass{article}
\usepackage{forloop,longtable}
\newcounter{count}
\setcounter{count}{1}
\makeatletter
\newbox\LT@secondhead
\def\endsecondhead{\LT@end@hd@ft\LT@secondhead}
\def\LT@output{%
  \ifnum\outputpenalty <-\@Mi
    \ifnum\outputpenalty > -\LT@end@pen
      \LT@err{floats and marginpars not allowed in a longtable}\@ehc
    \else
      \setbox\z@\vbox{\unvbox\@cclv}%
      \ifdim \ht\LT@lastfoot>\ht\LT@foot
        \dimen@\pagegoal
        \advance\dimen@-\ht\LT@lastfoot
        \ifdim\dimen@<\ht\z@
          \setbox\@cclv\vbox{\unvbox\z@\copy\LT@foot\vss}%
          \@makecol
          \@outputpage
          \ifvoid\LT@secondhead
           \setbox\z@\vbox{\box\LT@head}%
          \else
           \setbox\z@\vbox{\box\LT@secondhead}%
          \fi
        \fi
      \fi
      \global\@colroom\@colht
      \global\vsize\@colht
      \vbox
        {\unvbox\z@\box\ifvoid\LT@lastfoot\LT@foot\else\LT@lastfoot\fi}%
    \fi
  \else
    \setbox\@cclv\vbox{\unvbox\@cclv\copy\LT@foot\vss}%
    \@makecol
    \@outputpage
      \global\vsize\@colroom
      \ifvoid\LT@secondhead
         \copy\LT@head\nobreak
      \else
         \box\LT@secondhead\nobreak
      \fi
  \fi}
\makeatother


\begin{document}
\listoftables
\section{section}
\begin{longtable}{c}
\caption{foo}\\\stepcounter{table}\endfirsthead
\caption{foo bar}\\\stepcounter{table}\endsecondhead
\caption{bar}\\\endhead
\whiledo{\value{count} < 100}{\stepcounter{count}
   \arabic{count} \\}
\end{longtable}
\end{document}