How can I set the width of `lrbox` in latex?

Question

I need to set the width of lrbox to a particular size. I am trying with the following code:

\begin{lrbox}[width=.5\linewidth]
  ...
\end{lrbox}

However, it is throwing error. Any idea how can I set the width of lrbox? Thanks

Answer 1

Welcome! You can use e.g. \makebox or \parbox.

\documentclass{article}
\newsavebox\mybox
\begin{document}
\begin{lrbox}\mybox
\makebox[.5\linewidth][l]{pft}
\end{lrbox}

\usebox\mybox
\medskip

The width of the \texttt{lrbox} is \texttt{\the\wd\mybox}, and the line width is
\texttt{\the\linewidth}.
\bigskip

\begin{lrbox}\mybox
\parbox{.5\linewidth}{pft pft pft pft pft pft pft pft pft pft pft pft pft pft pft pft pft pft pft pft pft pft}
\end{lrbox}

\usebox\mybox
\medskip

The width of the \texttt{lrbox} is \texttt{\the\wd\mybox}, and the line width is
\texttt{\the\linewidth}.

\end{document}

Further options include using a minipage.