# Chemnum does not work since last l3package udpate

I am using chemnum package and since last updates of l3packages, l3kernel and l3experimental when I compile my code there are 14 errors. The first one is:

LaTeX error: "kernel/command-not-defined"

Control sequence \chemnum_aux_file undefined

Despite this error the code is working and it gives me a good output, but this error should mean something:

\documentclass[a4paper, 10pt]{report} %environnement du document
\usepackage[latin1]{inputenc}
\usepackage[T1]{fontenc} %prise en charge des caractères spéciaux
\usepackage[frenchb]{babel} %langue
\usepackage{mathrsfs}
\usepackage{graphicx} %prise en charge des graphiques eps
\usepackage{geometry}
\usepackage{epstopdf}
\geometry{margin=55pt} %marges
\usepackage{indentfirst} %indentation après le titre de section
\usepackage[bottom]{footmisc} %bas de page en toute fin de page
\usepackage{csquotes} %pour la biblio
\usepackage{lmodern}
\usepackage[intoc]{nomencl}
\usepackage[backend=biber,style=chem-acs,subentry,maxnames=20]{biblatex} %style acs
\bibliography{library}
\usepackage{caption}
\usepackage{chemnum,chemstyle,chemscheme}%pour les schémas de chimie
%\usepackage[runs=2]{auto-pst-pdf}

\usepackage[version=3]{mhchem}  %prise en charge de l'écriture chimique

\begin{document}

\begin{scheme}[H] %le H permet de fixer l'image ici
\centering
\cmpdref{CM52}
\cmpdref{CM53}
\cmpdref{CM54}
\cmpdref{CM55}
\includegraphics[scale=0.80]{schema/13.eps}
\caption{}
\label{13} %permet de faire reference dans le texte
\end{scheme}

\end{document}


Is there a way to fix it?

-
A number of things appear to have been broken by recent updates to l3kernel and l3packages. For example, I (and others) are finding that unicode-math no longer works as it should. –  Evan Cooch Jul 25 '12 at 15:10

I already fixed that and sent an update to CTAN. Version 0.5c is already available there.

-
Ok, I will update teh package –  Thomas C Jul 25 '12 at 15:27
@cgnider Could I check exactly what broke: we did try to avoid any issues, so I wonder which change in the code caused this. –  Joseph Wright Jul 25 '12 at 16:15
@JosephWright chemnum writes the compound numbers to an aux file \chemnum_aux_file: and chemnum was missing a \iow_new:N \chemnum_aux_file: so this was rather a bug in chemnum, I guess. –  cgnieder Jul 25 '12 at 16:21
@JosephWright in another of my packages I had troubles, though, as it was relying on xparse's (now missing) \NoValue to fool some commands to be fed with no value instead of an empty one. I fixed that, too, and probably should have designed the function using it differently in the first place, so ... –  cgnieder Jul 25 '12 at 16:27
@cgnieder On the first point: OK, that was one of the 'breaking' changes we knew about. On the second point: Part of the reason for the change was that having \NoValue 'accessible' was asking for trouble, as there was the danger of people doing \foo[\NoValue] which was never the intention. So again this is 'to be expected'. I assume you are on LaTeX-L if only to pick up my announcements? –  Joseph Wright Jul 25 '12 at 16:32