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I'm using the IEEEconf documentclass. I want the abstract to span two columns directly after the title so I added the following:

\twocolumn[
    \begin{@twocolumnfalse}
        \maketitle
    \end{@twocolumnfalse}
    \vspace{2mm}
    \hrule
    \begin{abstract}
        abstract text.
    \end{abstract}
    \hrule
    \bigskip
]

When I build this with XeLaTex, I get the following error:

Undefined control sequence. []]

However, when I first comment out the lines with \twocolumn[ and ], keep the pdf open and build again, I keep getting the error, but the pdf is build normally. How can I prevent the error or tell XeLaTex to ignore this error?

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closed as unclear what you're asking by egreg, Romain Picot, darthbith, Kurt, moewe Feb 22 at 14:10

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question.If this question can be reworded to fit the rules in the help center, please edit the question.

    
Can you really use @twocolumnfalse outside a class or style file without \makeatletter? – Crissov Feb 3 '14 at 16:16
    
I really don't understand, what you are doing. Usually you can write the text which you wish to have in one column just inside the []: \twocolumn[This will be printed in one column!] and this in two columns. OK, did not test, but write from memory, hopefully its true. – Keks Dose Feb 3 '14 at 16:31
    
\twoculumn forces a pagebreak, that is why the maketitle is within the \twocolumn. The reason for the @twocolumnfalse environment is that \maktetitle already spans the two columns. See also here: tex.ac.uk/cgi-bin/texfaq2html?label=onecolabs and here: tex.stackexchange.com/a/140679so it should work. Maybe XeLaTex is the problem? – SeeDoubleYou Feb 3 '14 at 20:11
    
It might help if you provided a proper compilable example people could play with. – Seamus Feb 22 at 13:48

The following complete example gives no error with a current xelatex

enter image description here

\documentclass{IEEEconf}
\begin{document}
\title{zzz}
\author{z. zz}

\twocolumn[
    \begin{@twocolumnfalse}
        \maketitle
    \end{@twocolumnfalse}
    \vspace{2mm}
    \hrule
    \begin{abstract}
        abstract text.
    \end{abstract}
    \hrule
    \bigskip
]

aaa
\end{document}
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\documentclass{IEEEconf}
\author{Foo}
\title{bar}

\usepackage{blindtext}
\begin{document}
\twocolumn[
  \maketitle
  \hrulefill
  \abstract
  \blindtext
  \endabstract\par
  \vspace{-\medskipamount}
  \hrulefill
  \medskip
]

\blindtext
\end{document}

enter image description here

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