[Tex/LaTex] Cross-referencing between two files in overleaf

#refcross-referencingexternal filesoverleafxr

I have two files, SI.tex and main.tex. There is a subsection in main.tex that is labeled subsec:A. I want to reference this subsection from SI.tex. I'm doing this in overleaf, just in case that makes a difference. I tried using xr:

\usepackage{xr}
\externaldocument{main}

...

\begin{document}
...
\ref{subsec:A}
...
\end{document}

This results in ?? in the output, and a warning in Overleaf saying LaTeX Warning: Reference 'subsec:protein' on page 3 undefined on input line 123.

What could be the problem?

Edit: I just tried this locally, without using Overleaf, and it gives the following warning, which is perhaps more descriptive:

W: /../test.tex:0 No file main.auxLABELS NOT IMPORTED.

Best Answer

Try recompiling your document from scratch in Overleaf. To the right of the "Recompile" button, choose the dropdown menu option "Recompile from scratch". I followed the guide provided by Overleaf for xr package implementation, but to no avail. It wasn't until I recompiled my project from scratch that I noticed a change! I think this should be added to their documentation.

Contents of file `CommonMacros.tex`:

\newcommand*{\SolutionBook}{SoluBook.pdf}
\newcommand*{\ExerciseBook}{MainBook.pdf}

\newcommand*{\exercisename}[1]{Exercise~#1.}
\newcommand*{\exercisecategory}{exercise}
\newcommand*{\solutionname}[1]{Solution of Exercise~#1.}
\newcommand*{\solutioncategory}{solution}

% In the following two commands, #1 stands for the part that is to be made
% clickable:
\newcommand*{\seeexercisephrase}[1]{See exercise #1.}
\newcommand*{\seesolutionphrase}[1]{See solution #1.}
\newcommand*{\herename}{here}

\newcommand*{\exesolubreak}{%
    \addpenalty{-200}%
    \addvspace{\bigskipamount}%
}

\newcounter{exercise}[section]
\renewcommand*{\theexercise}{\thesection.\arabic{exercise}}
\newenvironment*{exercise}{%
    \exesolubreak
    \noindent
    \refstepcounter{exercise}%
    \hyperdef{\exercisecategory}{\theHexercise}%
        {\textbf{\exercisename{\theexercise}}}%
    \nobreak\quad
    \ignorespaces
}{%
    \par
    \nobreak\smallskip
    \begingroup
        \footnotesize
        \noindent
        \seesolutionphrase{%
            \hyperref{\SolutionBook}{\solutioncategory}{\theHexercise}%
                {\herename}%
        }%
        \par
    \endgroup
    \addvspace{\bigskipamount}%
}

% In a real-life example, the two books would "communicate" through some sort 
% of auxiliary file; here, we assume that each solution correspond to the 
% exercise with the same number.
\newcounter{solution}[section]
\renewcommand*{\thesolution}{\thesection.\arabic{solution}}
\newenvironment*{solution}{%
    \exesolubreak
    \noindent
    \refstepcounter{solution}%
    \hyperdef{\solutioncategory}{\theHsolution}%
        {\textbf{\solutionname{\thesolution}}}%
    \nobreak\quad
    \ignorespaces
}{%
    \par
    \nobreak\smallskip
    \begingroup
        \footnotesize
        \noindent
        \seeexercisephrase{%
            \hyperref{\ExerciseBook}{\exercisecategory}{\theHsolution}%
                {\herename}%
        }%
        \par
    \endgroup
    \addvspace{\bigskipamount}%
}

Contents of file `MainBook.tex`:

% My standard header for TeX.SX answers:
\documentclass[a4paper]{article} % To avoid confusion, let us explicitly 
                                 % declare the paper format.

\usepackage[T1]{fontenc}         % Not always necessary, but recommended.
% End of standard header.  What follows pertains to the problem at hand.

\usepackage{hyperref}
\usepackage{lipsum}

\input{CommonMacros}



\begin{document}

\section{Some argument}

\lipsum[1-2]

\begin{exercise}
    \lipsum*[\arabic{exercise}]
\end{exercise}

\lipsum[3]

\begin{exercise}
    \lipsum*[\arabic{exercise}]
\end{exercise}

\lipsum[4-6]

\begin{exercise}
    \lipsum*[\arabic{exercise}]
\end{exercise}

\lipsum[7-8]

\begin{exercise}
    \lipsum*[\arabic{exercise}]
\end{exercise}

\lipsum[9]

\begin{exercise}
    \lipsum*[\arabic{exercise}]
\end{exercise}



\section{Another argument}

\lipsum[10]

\begin{exercise}
    \lipsum*[1\arabic{exercise}]
\end{exercise}

\lipsum[11-12]

\begin{exercise}
    \lipsum*[1\arabic{exercise}]
\end{exercise}

\lipsum[13]

\begin{exercise}
    \lipsum*[1\arabic{exercise}]
\end{exercise}

\lipsum[14]

\begin{exercise}
    \lipsum*[1\arabic{exercise}]
\end{exercise}

\lipsum[15-16]

\begin{exercise}
    \lipsum*[1\arabic{exercise}]
\end{exercise}

\end{document}

Contents of file `SoluBook.tex`:

% My standard header for TeX.SX answers:
\documentclass[a4paper]{article} % To avoid confusion, let us explicitly 
                                 % declare the paper format.

\usepackage[T1]{fontenc}         % Not always necessary, but recommended.
% End of standard header.  What follows pertains to the problem at hand.

\usepackage{hyperref}
\usepackage{lipsum}

\input{CommonMacros}



\begin{document}

\section{Some argument}

\begin{solution}
    \lipsum*[\arabic{solution}]
\end{solution}

\begin{solution}
    \lipsum*[\arabic{solution}]
\end{solution}

\begin{solution}
    \lipsum*[\arabic{solution}]
\end{solution}

\begin{solution}
    \lipsum*[\arabic{solution}]
\end{solution}

\begin{solution}
    \lipsum*[\arabic{solution}]
\end{solution}



\section{Another argument}

\begin{solution}
    \lipsum*[1\arabic{solution}]
\end{solution}

\begin{solution}
    \lipsum*[1\arabic{solution}]
\end{solution}

\begin{solution}
    \lipsum*[1\arabic{solution}]
\end{solution}

\begin{solution}
    \lipsum*[1\arabic{solution}]
\end{solution}

\begin{solution}
    \lipsum*[1\arabic{solution}]
\end{solution}

\end{document}

Now, compile the files MainBook.tex and SoluBook.tex. Ignore warnings about duplicate destinations, they are absolutely normal since more than one exercise/solution winds up on the same page. The resulting two files MainBook.pdf and SoluBook.pdf should exhibit the requested behavior.

Best Answer

Related Solutions

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Contents of file CommonMacros.tex:

Contents of file MainBook.tex:

Contents of file SoluBook.tex:

Related Question

Contents of file `CommonMacros.tex`:

Contents of file `MainBook.tex`:

Contents of file `SoluBook.tex`: