# Change the background color of line numbers in a lstlisting?

Consider the following code which deals with a lstlisting.

\documentclass{article}

\usepackage[T1]{fontenc}
\usepackage{listings}
\usepackage{xcolor}
\lstset{basicstyle=\small\ttfamily,keywordstyle=\color{blue},language=C++,showstringspaces=false,tabsize=2,numbers=left}
\begin{document}

\begin{lstlisting}
#include <stdio.h>
int main(void) {
printf("Hello World!");
return 0;
}
\end{lstlisting}

\end{document}


Is there a way to coulour the background of line numbers (in grey for example) but not the background of the code ?

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listings doesn't have a predefined option for this, but if you are willing to use the tcolorbox package, which has a nice interaction with the listings package, here's how you can do it:

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[many]{tcolorbox}
\tcbuselibrary{listings}

\newtcblisting{mycpp}{
colback=white,
boxrule=0pt,
arc=0pt,
outer arc=0pt,
top=0pt,
bottom=0pt,
colframe=white,
listing only,
left=15.5pt,
enhanced,
listing options={
basicstyle=\small\ttfamily,
keywordstyle=\color{blue},
language=C++,
showstringspaces=false,
tabsize=2,
numbers=left
},
overlay={
\fill[gray!30]
([xshift=-3pt]frame.south west)
rectangle
([xshift=11.5pt]frame.north west);
}
}

\begin{document}

\begin{mycpp}
#include <stdio.h>
int main(void) {
printf("Hello World!");
return 0;
}
int main(void) {
printf("Hello World!");
return 0;
}
int main(void) {
printf("Hello World!");
return 0;
}
\end{mycpp}

\end{document}


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Thanks ! If you have an idea for this question tex.stackexchange.com/questions/176431/… It would be fantastic ! –  Vincent May 10 at 17:31
@Vincent You're welcome! Right now I have to leave but in some hours I can take a look at the other question (if no one else has provided an answer by then). –  Gonzalo Medina May 10 at 17:47

Another way would be to work with frames and their margins so you can use the normal lstlisting command.

\lstset {
...
frame=l,
framesep=4.5mm,
framexleftmargin=2.5mm,
fillcolor=\color{numberbg},
rulecolor=\color{ballblue},
numberstyle=\normalfont\tiny\color{numbercolor}
}


This snippet will result in following style:

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