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

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