fancyhdrheader-footertable of contents
I would like to use \leftmark and \rightmark, but have "Contents" appear only once (on the left) in the header. Instead, it appears as both the \leftmark and the \rightmark.
The following MWE illustrates the problem:
\documentclass[12pt]{article}
\usepackage{fancyhdr}
\pagestyle{fancy}
\lhead{\leftmark}
\rhead{\rightmark}
\begin{document}
\tableofcontents
\end{document}
This is answered in the TeX FAQ. On the left-hand pages the text used in the title is that of the first mark on the page, so your \subsectionmark is coming too late. This can be solved by adding this command again in the title itself:
\documentclass[a4paper,10pt]{scrartcl}
\usepackage[utf8x]{inputenc}
\usepackage{lipsum}
\usepackage{fancyhdr}
\pagestyle{fancy}
\begin{document}
\tableofcontents
\section[some section with quite a lengthy title]{some section with quite
a lengthy title%
\sectionmark{short section}}
\sectionmark{short section}
\lipsum
\subsection[very very very long title of subsection]{very very very long
title of subsection%
\subsectionmark{short subsection}}
\subsectionmark{short subsection}
\lipsum
\end{document}
Because of the way the writing to the table of contents works you will also have to add the full title to the optional argument of the \(sub)section command, as above. As this is rather clumsy, it is reasonable to introduced commands such as \markedsection to achieve this:
\documentclass[a4paper,10pt]{scrartcl}
\usepackage[utf8x]{inputenc}
\usepackage{lipsum}
\usepackage{fancyhdr}
\pagestyle{fancy}
\newcommand{\markedsection}[2]{\section[#2]{#2%
\sectionmark{#1}}
\sectionmark{#1}}
\newcommand{\markedsubsection}[2]{\subsection[#2]{#2%
\subsectionmark{#1}}
\subsectionmark{#1}}
\begin{document}
\tableofcontents
\markedsection{short section}{Some section with quite a lengthy title}
\lipsum
\markedsubsection{short subsection}{Very very very long title of subsection}
\lipsum
\end{document}
For the standard cases, you can still use the ordinary commands.
If your are prepared to switch to the memoir class, then you will have sectioning commands that help this proceedure as they have two optional arguments: one for the head and one for the table of contents.
You can test if the \rightmark is empty by fully expanding it; the command \rightorleftmark will do what you want (uncomment the \section line to see the difference).
\documentclass{book}
\usepackage{fancyhdr}
\pagestyle{fancy}
\fancyhf{}
\lhead{\nouppercase{\rightorleftmark}}
\rhead{\thepage}
\makeatletter
\newcommand{\rightorleftmark}{%
\begingroup\protected@edef\x{\rightmark}%
\ifx\x\@empty
\endgroup\leftmark
\else
\endgroup\rightmark
\fi}
\makeatother
\begin{document}
\mainmatter
\chapter{A}
%\section{B}
abc\newpage
def\newpage
\end{document}
Best Answer
Change the definition of
\tableofcontents.