section, (\ref{eq:splines:3})}: can't compile

[Uwe Brauer]

Hello the following minimal example fails:

\documentclass{beamer}
\begin{document}
\section{Main}
\label{sec:main}

\begin{frame}[<+->]
\frametitle{Main}
this

\begin{equation}
\label{eq:splines:3}
\int dx
\end{equation}
\end{frame}
\subsection{Test equation \protect (\ref{eq:splines:3})}
\begin{frame}[<+->]
\frametitle{Test}
this
\end{frame}
\end{document}

The error message is as follows, any help would be greatly appreciated

Uwe Brauer

LaTeX Font Warning: Font shape `OT1/cmss/m/n' in size <4> not available
(Font) size <5> substituted on input line 14.

[1{/usr/local/texlive/2016/texmf-var/fonts/map/pdftex/updmap/pdftex.map}]
./testbeamer.tex:15: Argument of \@gobble has an extra }.
<inserted text>
\par
l.15 ...t equation \protect (\ref{eq:splines:3})}

Runaway argument?
./testbeamer.tex:15: Paragraph ended before \@gobble was complete.
<to be read again>
\par
l.15 ...t equation \protect (\ref{eq:splines:3})}

./testbeamer.tex:15: Argument of \@firstofone has an extra }.
<inserted text>
\par
l.15 ...t equation \protect (\ref{eq:splines:3})}

Runaway argument?
./testbeamer.tex:15: Paragraph ended before \@firstofone was complete.
<to be read again>
\par
l.15 ...t equation \protect (\ref{eq:splines:3})}

./testbeamer.tex:15: Undefined control sequence.
\beamer@saveanother ->\let \beamer@savedif
=\ifbeamer@anotherslide
l.15 ...t equation \protect (\ref{eq:splines:3})}

)
! Incomplete \iffalse; all text was ignored after line 15.
<inserted text>
\fi
<*> \input testbeamer.tex

! Emergency stop.
<*> \input testbeamer.tex

! ==> Fatal error occurred, no output PDF file produced!
Transcript written on testbeamer.log.

TeX Output exited abnormally with code 1 at Mon Jan 30 12:23:23

[Louis Stuart]

Just use `\protect` exactly before `\ref`.

在 2017年1月30日星期一 UTC+8下午8:27:50，Uwe Brauer写道：