How to display headers bold?

Question

Is there a way to change the headers in XeLaTeX? Basically I just want my headers (pagenumber, author and title) to be bold, but none of the solutions suggested for LaTeX seems to have any effect on the headers. Is it because I'm using XeLaTeX? Here's my code:

\documentclass[twoside,12pt]{book}

\usepackage{fancyhdr}
\pagestyle{fancy}
\fancyhf{}

\begin{document}

\fancyhead{}
\fancyhead[LE,RO]{\bfseries \thepage}
\fancyhead[CO]{Titleoftext \bfseries}
\fancyhead[CE]{\bfseries Authoroftext}

\end{document}

Answer 1

If I add to your code snippet the missing parts it does what you want:

\listfiles
\documentclass[twoside]{book}
\usepackage{fancyhdr} 
\pagestyle{fancy}
\fancyhf{}
\fancyhead[LE,RO]{\bfseries \thepage}
\fancyhead[CO]{\bfseries Titleoftext }
\fancyhead[CE]{\bfseries Authoroftext}

\begin{document}
foo  \newpage bar

\end{document}

the file list:

*File List*
book.cls 2007/10/19 v1.4h Standard LaTeX document class
bk10.clo 2007/10/19 v1.4h Standard LaTeX file (size option)
fancyhdr.sty
***********