%%
%% This is file `zref-example-nextpage.tex',
%% generated with the docstrip utility.
%%
%% The original source files were:
%%
%% zref.dtx  (with options: `example-nextpage')
%% 
%% This is a generated file.
%% 
%% Project: zref
%% Version: 2022-04-07 v2.34
%% 
%% Copyright (C)
%%   2006-2012 Heiko Oberdiek
%%   2016-2022 Oberdiek Package Support Group
%% 
%% This work may be distributed and/or modified under the
%% conditions of the LaTeX Project Public License, either
%% version 1.3c of this license or (at your option) any later
%% version. This version of this license is in
%%    https://www.latex-project.org/lppl/lppl-1-3c.txt
%% and the latest version of this license is in
%%    https://www.latex-project.org/lppl.txt
%% and version 1.3 or later is part of all distributions of
%% LaTeX version 2005/12/01 or later.
%% 
%% This work has the LPPL maintenance status "maintained".
%% 
%% The Current Maintainers of this work are
%% Heiko Oberdiek and the Oberdiek Package Support Group
%% https://github.com/ho-tex/zref/issues
%% 
%% This work consists of the main source file zref.dtx
%% and the derived files
%%    zref.sty, zref.pdf, zref.ins, zref.drv, zref-base.sty,
%%    zref-abspage.sty, zref-abspos.sty, zref-counter.sty,
%%    zref-dotfill.sty, zref-env.sty, zref-hyperref.sty,
%%    zref-lastpage.sty, zref-marks.sty, zref-nextpage.sty,
%%    zref-pageattr.sty, zref-pagelayout.sty, zref-perpage.sty,
%%    zref-runs.sty, zref-savepos.sty, zref-thepage.sty,
%%    zref-titleref.sty, zref-totpages.sty, zref-user.sty,
%%    zref-xr.sty, zref-example.tex, zref-example-lastpage.tex,
%%    zref-example-nextpage.tex, zref-test1.tex,
%%    zref-test-base.tex, zref-test-runs.tex,
%%    zref-test-titleref-memoir.tex.
%% 
\documentclass{book}

\usepackage{zref-nextpage}[2019/11/29]
\znextpagesetup
  {\thepage}% next page is unknown
  {\thepage\ (#1)}% this page is last page
  {\thepage\ $\rightarrow$ #1}% next page is known
\renewcommand*{\znonextpagename}{last page}

\usepackage{fancyhdr}
\pagestyle{fancy}
\fancyhf{}
\fancyhead[LE,RO]{\znextpage}
\fancypagestyle{plain}{%
  \fancyhf{}%
  \fancyhead[LE,RO]{\znextpage}%
}

\begin{document}
\frontmatter
  \tableofcontents
\mainmatter
  \chapter{Hello World}
  \clearpage
  \section{Last section}
\end{document}
\endinput
%%
%% End of file `zref-example-nextpage.tex'.
