我有以下代码,在绘制红色箭头的行上引发“未定义控制序列”错误。当我继续编译时,它确实产生了红色箭头,但给出了这个我无法弄清楚的错误。
\documentclass{scrartcl}
\usepackage{tikz}
\usetikzlibrary{shapes,positioning,arrows}
\tikzstyle{redarrow}=[->, >=triangle 90,dashed, red]
\tikzstyle{every entity} = []
\tikzstyle{smentity} = [rectangle, draw, black,
minimum width=4em, minimum height=2em,
every entity]
\begin{document}
\begin{tikzpicture}[node distance=1cm, every edge/.style={link}]
\node[smentity] (d1) {1111 1101};
\draw[redarrow] (d1.130) -- ++(0,0.4) node[above]{\alert{11101}} -| (d1.35);
\end{tikzpicture}
\end{document}