# Why does latex throw an error when there is empty lines inside the caption environment

Here is an effect i've irritated me on for a while.

When creating a figure environment with a caption like the one below

\begin{figure}[ht]
%%%Some figure
\caption{Some text
some more text

some text after a double line break}
\end{figure}


latex throws an error if I leave any line empty.

pdfTeX warning: pdflatex (file my_file.pdf): PDF inclusion: multiple pdfs with page group included in a single page >] Runaway argument? {Some text some more text ! Paragraph ended before \caption@prepareanchor was complete. \par l.xxx some text after a double line break}

My simple and maybe naive question is, why is this? Can one get around it except by adding a comment '%' in the gap of the empty line?

• The error message and the resolution is listed in the caption package documentation, section A.4 "Errors". – Axel Sommerfeldt Nov 5 '18 at 9:54

The error from

\documentclass{article}

\begin{document}

\begin{figure}[ht]
%%%Some figure
\caption{Some text
some more text

some text after a double line break}
\end{figure}
\end{document}


is

! Paragraph ended before \addcontentsline was complete.


because the standard table of contents code is not set up for multi-paragraph captions, so you can supply a short version for the toc:

\documentclass{article}

\begin{document}

\begin{figure}[ht]
%%%Some figure
\caption[zz]{Some text
some more text

some text after a double line break}
\end{figure}
\end{document}

• maybe i'm blind by i dont see the difference between the two code snippets... – Mikael Fremling Nov 5 '18 at 9:58
• @MikaelFremling oops I put the corrected version in twice, I'll delete [zz] from the first one, thanks!!!! – David Carlisle Nov 5 '18 at 10:06