Multiline comment

Question

In tex there is a way to do a comment multiline like in C, C++ /* comment */ or in HTML <!-- comment -->? I'm currently using \ifx

\ifx true false
My multiline comment
that will not be in the
output pdf
\fi

but this may create a problem if I put inside the comment something like \someundefcommand. I wish something like the standard % comment so I can put inside the comment I want.

Answer 1

Use the verbatim package.

\documentclass{article}
\usepackage{verbatim}
\begin{document}
\begin{comment}
some comment
\someundefinedcommand
\end{comment}
a
\end{document}

Answer 2

Instead \ifx true false you may use the shorter

\iffalse
dsaads
fdfdfds
\fi

If you ever want to have to 'activate' your comments later, you may define your own if:

\documentclass{article}

\newif\ifcomment
%\commenttrue # Show comments
\begin{document}

b

\ifcomment
dsaads
fdfdfds
\fi

a
\end{document}

But I would not recommend the \ifcomment. There are packages for this (the already mentioned verbatim or comment or version or versions).

Another interesting approach could be todonotes. Just don't show the todos. If you need them, you may define, where you get them (margin, footnote, own pages...)