Is there a way to force LaTeX to issue a warning if a figure is never referenced?

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How can I get LaTeX to warn about unreferenced figures?

In my document I have several figures, most of which I created references for (using \ref{}) immediately after I placed them into the document. However, I had a few figures that I forgot to reference in the document, leaving some figures "hanging" without any citation, which is a mistake on my part and must be corrected.

So, my questions is:

Is there a way to force latex to issue a warning if a figure is never referenced?

Are all figures labeled? – Marco Daniel Dec 03 '11 at 20:14 — Marco Daniel, Dec 03 '11 at 20:14
Yes, in my case all of the figures are labeled. – nickb Dec 03 '11 at 20:14 — nickb, Dec 03 '11 at 20:14

cmhughes · Accepted Answer · 2011-12-03T23:32:45.293

17

The refcheck package might be useful here.

The following MWE has a figure that is not referenced, so the refcheck puts a warning in your pdf with ? surrounding it.

enter image description here

\documentclass{article}
\usepackage{refcheck}

\begin{document}

\begin{figure}
 \centering
 \rule{20pt}{30pt}
 \caption{}
 \label{fig:myfig}
\end{figure}
\end{document}

As soon as you reference the figure, the ? will be removed. Note that this method does rely on each figure having a label.

Note that I have demonstrated refcheck with a figure, but it works in the same way for anything that has a label (table, chapter, equation, etc).

edited Dec 03 '11 at 23:32

answered Dec 03 '11 at 20:18

cmhughes

100,947

That's a neat package I'd never heard of. Thanks! – Alan Munn Dec 03 '11 at 20:34
That's quite useful. However, is there a way to have refcheck loaded, and not have the <fig:myfig> in the margin, once the figure is referenced. – Peter Grill Dec 03 '11 at 20:34
@PeterGrill Good question, not sure! I usually just comment out %\usepackage{refcheck} when I'm done checking – cmhughes Dec 03 '11 at 20:42

celtschk · Answer 2 · 2011-12-03T22:10:59.483

Here's a hand-made solution:

Add the following to your preamble:

\makeatletter

\let\LaTeX@original@label\label
\let\LaTeX@original@ref\ref

\newcommand{\warnunused}{}

\renewcommand{\label}[1]{%
  \expandafter\global\expandafter\def\csname warning@#1\endcsname{%
    \typeout{warning: label #1 was not referenced.}}%
  \g@addto@macro\warnunused{%
    \csname warning@#1\endcsname}
  \LaTeX@original@label{#1}}

\renewcommand{\ref}[1]{%
  \expandafter\global\expandafter\def\csname warning@#1\endcsname{}
  \LaTeX@original@ref{#1}}

\makeatother

and the following directly before \end{document}:

\warnunused

Now on every LaTeX run, for each unreferenced label you get a line

warning: label (your label here) was not referenced.

on your standard output and in your refwarn.log.

If you prefer the warning directly in your document instead, remove the \typeout (and possibly add a \texttt around the #1 and a \\ at the end) in the warning macro.

Is there a way to force LaTeX to issue a warning if a figure is never referenced?

2 Answers2