C preprocessor commands in listings package

Question

I am using the listings package, which is mostly formatting things nicely. However, it fails to syntax highlight indented preprocessor commands correctly.

For example,

\documentclass{article}
\usepackage{listings}
\begin{document}
\lstset{language=C}
\begin{lstlisting}
#if SYSTEM == SYSV
#    define HDR "sysv.h"
#if SYSTEM == SYSV
    #define HDR "sysv.h"
\end{lstlisting}
\end{document}

The first #define keyword is highlighted properly, but the second #define keyword is not highlighted at all. For old compilers, the # symbol had to the be first character of preprocessor commands, but modern style prefers the latter system for indentation. So, I would prefer to indent the # symbol.

Are there any ways I can indent this symbol and have the syntax highlighting come out correctly in the listings package?

Answer 1

If you add \lstset{otherkeywords={define,\# }}, then the output should be what you are looking for:

It appears that the # and if are highlighted separately. You can see that if you attempt to use #ifx, then the # is still highlighted, but not the ifx. So by specifying that define is to be treated as a keyword, you get the desired results.

Code:

\documentclass{article}
\usepackage{listings}
\begin{document}
\lstset{language=C}
\lstset{otherkeywords={define,\# }}%

\begin{lstlisting}
#if SYSTEM == SYSV
#    define HDR "sysv.h"
#if SYSTEM == SYSV
    #define HDR "sysv.h"
\end{lstlisting}
\end{document}