Exotic symbol in the argument of \section

Question

I need an exotic symbol in the title of a section (the class is book). So, I write \section{Bla-bla \hbox{\usefont{U}{MnSymbolC}{m}{n}\char"36} tititi}. It works perfectly well in the title, but in the running title the symbol just disappears, it is

Bla-bla tititi

What can be done?

Answer 1

For the running title you need to stop \MakeUpperCase changing your symbol. One way to this is to define a command for the symbol, which you can use anywhere, and in section titles proceed it by \protect. A simpler solution is to define the command via \DeclareRobustCommand:

\documentclass{article}

\usepackage{MnSymbol}

\DeclareRobustCommand{\mysymb}{{\usefont{U}{MnSymbolC}{m}{n}\symbol{"36}}}

\pagestyle{headings}
\begin{document}

\section{Bla-bla \mysymb{} tititi}

\end{document}

Defining the symbol this way allows it to change size with the surrounding text. Note that I have changed \char to \symbol{...} as recommended by egreg.