Question

This is what the code looks in Xcode.

And this in my listing created with texlive.

And yes I used basicstyle=\ttfamily . Having looked at the manual of listings I haven’t found anything about fixed-with or monospace fonts..

Example to reproduce

\documentclass[
  article,
  a4paper,
  a4wide,
  %draft,
  smallheadings
]{book}

% Packages below
\usepackage{graphicx}
\usepackage{verbatim} % used to display code
\usepackage{hyperref}
\usepackage{fullpage}
\usepackage[ansinew]{inputenc} % german umlauts
\usepackage[usenames,dvipsnames]{color}
\usepackage{float}
\usepackage{subfig}
\usepackage{tikz}
\usetikzlibrary{calc,through,backgrounds}
\usepackage{fancyvrb}
\usepackage{acronym}
\usepackage{amsthm} % Uuhhh yet another package
\VerbatimFootnotes % Required, otherwise verbatim does not work in footnotes!
\usepackage{listings}

\definecolor{Brown}{cmyk}{0,0.81,1,0.60}
\definecolor{OliveGreen}{cmyk}{0.64,0,0.95,0.40}
\definecolor{CadetBlue}{cmyk}{0.62,0.57,0.23,0}
\definecolor{lightlightgray}{gray}{0.9}

\begin{document}
\lstset{
language=C,                             % Code langugage
basicstyle=\ttfamily,                   % Code font, Examples: \footnotesize, \ttfamily
keywordstyle=\color{OliveGreen},        % Keywords font ('*' = uppercase)
commentstyle=\color{gray},              % Comments font
numbers=left,                           % Line nums position
numberstyle=\tiny,                      % Line-numbers fonts
stepnumber=1,                           % Step between two line-numbers
numbersep=5pt,                          % How far are line-numbers from code
backgroundcolor=\color{lightlightgray}, % Choose background color
frame=none,                             % A frame around the code
tabsize=2,                              % Default tab size
captionpos=b,                           % Caption-position = bottom
breaklines=true,                        % Automatic line breaking?
breakatwhitespace=false,                % Automatic breaks only at whitespace?
showspaces=false,                       % Dont make spaces visible
showtabs=false,                         % Dont make tabls visible
columns=flexible,                       % Column format
morekeywords={__global__, __device__},  % CUDA specific keywords
}

\begin{lstlisting}
    As[threadRow][threadCol] = A[
        threadCol + threadRow * Awidth   // Adress of the thread in the current block
        + i * BLOCK_SIZE                 // Pick a block further left for i+1
        + blockRow * BLOCK_SIZE * Awidth // for blockRow +1 go one blockRow down
    ];
\end{lstlisting}

\end{document}

Answer 1

The problem is the columns=flexible option. Remove it and it looks like you want it to look. At least, if there is no actual reason for you to use it. If there is, there is no way to have the monospaceness of your snippet to look like in Xcode :).