# XeLaTex Undefined control sequence []] with \twocolumn

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?

-
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