Subcaption package: compatibility issue

Question

There is a compatibility problem between the CIFA document class and the subcaption package. When I compile the following example (with PDFLaTex):

\documentclass{cifa}

\usepackage{subcaption}

\begin{document}
\begin{figure}
\parbox{4cm}{\subcaption{This is a subcaption}\label{sub}}

\caption{nothing}
\label{nothing}
\end{figure}

See figure \ref{nothing}: there is \ref{sub} inside...

\end{document}

These warnings are displayed:

Package caption Warning: Unsupported document class (or package) detected,

Package caption Warning: \caption will not be redefined since it's already

In addition the words "figure" and "subfigure" are displayed AFTER the captions.

How to fix this issue?

Answer 1

The very recent version of the subcaption package will even issue an error:

! Package caption Error: The `subcaption' package does not work correctly
(caption)                in compatibility mode.

The only way to get around this is to specify the option compatibility=false to the caption package:

\documentclass{cifa}

\usepackage{subcaption}
\captionsetup{compatibility=false}

\begin{document}
\begin{figure}
\parbox{4cm}{\subcaption{This is a subcaption}\label{sub}}
\caption{nothing}
\label{nothing}
\end{figure}

See figure \ref{nothing}: there is \ref{sub} inside...

\end{document}

PLEASE NOTE: This way the customization of the captions done by the cifa document class will be overwritten by the caption package in a brute-force manner. In best case the output of the captions will look different (and some caption-related stuff offered by the cifa document class will not work anymore), in worst case you'll get error messages and weird output. So please also take a look at the caption package documentation, section "6 Package Support". Since this is a perfect method to shoot oneself in the foot, an extra warning is always issued when using the compatibility=false option:

Package caption Warning: Forced redefinition of \caption since the
(caption)                unsupported(!) package option `compatibility=false'
(caption)                was given.
See the caption package documentation for explanation.

If you do not want this (or it does not work anyway) then the only solution left is not-using the subcaption package. Use the subfig package with option caption=false (which prevents loading of the caption package) instead:

\documentclass{cifa}

\usepackage[caption=false]{subfig}

\begin{document}
\begin{figure}
\subfloat[This is a subcaption\label{sub}]{............}
\caption{nothing}
\label{nothing}
\end{figure}

See figure \ref{nothing}: there is \ref{sub} inside...

\end{document}