One can't just do that:
\documentclass{book}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{hyperref}
\hypersetup{
unicode=true,
bookmarksnumbered=true
}
\begin{document}
\tableofcontents
\chapter{\MakeUppercase{First chapter}}% that doesn't work
\end{document}
I guess the command has to be "expanded" before using it for hyperref pdfstring?!
(I'd like to have the bookmarks-entries of \part-headings in all-caps. (Yet, the headings themselves formatted differently.) Basically I'd like to be able to use something like \mychapter{First chapter} in the document while having it all-caps in the bookmarks. I know that I can use \texorpdfstring{First chapter}{FIRST CHAPTER} but I'm looking for a solution which does it automatically.)