Undefined control sequence with \pagestyle{headings}

Question

The following code

\documentclass{beamer}
\pagestyle{headings}

\begin{document}
\begin{frame}
Hello beamer world.
\end{frame}
\end{document}

gives me

! Undefined control sequence.
<argument> \undefinedpagestyle 

while

\pagestyle{empty}

and

\pagestyle{plain}

work fine. Any ideas on how to solve this? Thanks in advance.

Answer 1

The pagestyles empty and plain are defined by default, see latex.ltx:

\def\ps@empty{%
  \let\@mkboth\@gobbletwo\let\@oddhead\@empty\let\@oddfoot\@empty
  \let\@evenhead\@empty\let\@evenfoot\@empty}
\def\ps@plain{\let\@mkboth\@gobbletwo
     \let\@oddhead\@empty\def\@oddfoot{\reset@font\hfil\thepage
     \hfil}\let\@evenhead\@empty\let\@evenfoot\@oddfoot}

where \ps@headings is not. For instance, the standard classes (article.cls, report.cls and book.cls) define this. Hence, you can't use it in beamer.

Apart from that it does not makes sense to use \pagestyle as headers/footers are built differently here. You should just cancel it out to fix your code.

Answer 2

beamer is not a standard class: it is a specialist class for making presentations. As such, you cannot expect that all of the standard LaTeX commands will do something appropriate or, even, be recognised.

The class provides a wide range of customisation options, including overall themes, inner themes, outer themes, font themes, colour themes and templates. Look at the documentation and/or around this site for examples.

Here is just one:

\documentclass{beamer}
\usetheme{Berlin}% overall theme: inner, outer & colours
\title{Title}
\subtitle{Sub-Title}
\author{Author}
\institute{Institute}
\begin{document}
  \begin{frame}
    \titlepage
  \end{frame}
  \section{Section}
  \begin{frame}
    Hello beamer world.
  \end{frame}
\end{document}