ModernCV creates a blank page

Question

I have created a text, but as an example I created this simple text

\documentclass[a4paper,12pt,danish]{moderncv}
\moderncvtheme{classic}
\usepackage{babel}
\usepackage{lipsum}
\pagestyle{empty}
\firstname{}
\familyname{}
\address{a\\b,}{c}
\begin{document}
\recipient{a}{a}
\opening{a}
\closing{a}
\makelettertitle
\lipsum[1-3]
\makeletterclosing
\end{document}

But I am wondering, why does this create a blank page as page 2?

Answer 1

If you look at the code for \makeletterclosing in the file moderncvstyleclassic.sty you will see the following:

\renewcommand*{\makeletterclosing}{
  \@closing\\[3em]%
  {\bfseries \@firstname~\@familyname}%
  \ifthenelse{\isundefined{\@enclosure}}{}{%
    \\%
    \vfill%
    {\color{color2}\itshape\enclname: \@enclosure}}}

There's a line break after \@closing with a vertical spacing of 3em, this causes the page break.

Add this to your document preamble, all I did is git rid of the forced line break.

\makeatletter
\renewcommand*{\makeletterclosing}{
  \@closing%\\[3em]%
  {\bfseries \@firstname~\@familyname}%
  \ifthenelse{\isundefined{\@enclosure}}{}{%
    \\%
    \vfill%
    {\color{color2}\itshape\enclname: \@enclosure}}}
\makeatother

A blank page doesn't appear if you used just two paragraphs of lipsum, i.e \lipsum[1-2]. So it's all about margins. Obviously, you don't want to delete the line break if you're going to insert a firstname and familyname since they will be in the same line as the closing.