# Multiline comment

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.

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Possible duplicate: Commenting out large sections –  diabonas Feb 12 '12 at 21:01

Use the verbatim package.

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

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Hmm. Why does verbatim provide this? I would expect to find it in its own package. Did the functionality fall out as a natural by-product of verbatim's implementation? –  Todd Lehman Feb 13 '12 at 12:24

Instead \ifx true false you may use the shorter

\iffalse
fdfdfds
\fi


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

\documentclass{article}

\newif\ifcomment
\begin{document}

b

\ifcomment
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...)

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A similar solution I came up with is to define a \comment command:

\newcommand{\comment}[1]{}


The command makes LaTeX ignore anything inside. This solution has the advantage over the other solutions (for me) of being a command rather than an environment with \begin/\end commands.

Usage:

Text that will be in the final document.
\comment{I am thinking of including this text,
but I don't want it in the compiled document right now.}
More text.


This can be modified à la @knut's answer to have an option for toggling the inclusion of the comments in the final document:

\newif\ifcomment

you can also use a delimited macro: \long\def\comment #1\endcomment{}. And as an alternative to using an \if, a companion command \newcommand\showcomments{\let\comment\empty\let\endcomment\empty}. The comment text should not be braced then to not create a group if the comments are to be shown. However, if the need arise to comment a whole block already containing commented out material, then do \comment{...the whole thing...}\endcomment. –  jfbu Nov 12 '13 at 18:49