# Compiling
This page contains help on compiling NetHack 3.6, either the officially released version (3.6.0) or the version from the development sources (as of 2016 October).  Compiling is necessary if you want to try out the dev team's latest changes when they haven't released a compiled version yet, or if you want to apply a patch, e.g. from the bilious database or make changes of your own.
Information about compiling NetHack 3.4.3 can still be found in an old version of this article, q.v..

Contents

1 Obtaining the officially released sources
2 Obtaining the development sources
3 Preparing to compile

3.1 Gathering build tools
3.2 Selecting a hints file
3.3 Modifying a hints file

4 Running the build setup script

4.1 Windows

5 Compiling
6 Installing
7 Creating the system config file

Obtaining the officially released sources
The official released NetHack source can be found here:
http://nethack.org/v360/download-src.html
Once you have obtained the tarball, you will need to extract it, either using standard tools (tar -xvf nethack-360-src.tgz) or some other archive extractor that can handle the tar and gzip formats.
Note that if you use a graphical archive extractor like 7zip, you may have to extract twice: once to decompress the gzip and obtain the plain tar file, and a second time to extract the actual contents.

Obtaining the development sources
The development source repository is available at http://git.code.sf.net/p/nethack/NetHack
If you have git installed, you can retrieve a copy of the repository using either of the following commands:
git clone https://github.com/NetHack/NetHack
alternately:
git clone http://git.code.sf.net/p/nethack/NetHack
(It doesn't matter which repository you use; they're both mirrors of the public portion of the dev team's repository.)
This will create a subdirectory (a.k.a., a "folder") called 'NetHack', in the current directory, and the new subdirectory, 'NetHack', will be a git repository, containing a working copy of the latest public development source for what will eventually become NetHack 3.6.1.

Preparing to compile
Gathering build tools
In order to build NetHack, you will neet at minimum the following tools:

a C compiler (typically 'gcc' or 'clang')
'make' (typically Gnu 'make', and note in particular that Microsoft's 'nmake' won't work)
'flex' and 'bison', or some other suitable lex/yacc implementation
common libraries (including development headers); these should be includeded if you have a complete working build environment (e.g., if you have installed build-essential on Debian-derived systems, you should have them).  I don't know a complete list of all the libraries that are required, but I believe the list includes standard POSIX regular expression libraries, termcap/terminfo, and of course the standard C library.  Beyond that, I'm not sure.
any libraries (including development headers) needed for the specific ports you wish to build; if this is the first time you are building NetHack, it is recommended that you start by building the Unix TTY port first, as it is the easiest and has no additional requirements of its own beyond the ones that all the ports require.
Note that you will need copies of all these on the platform for which you are building NetHack.  Cross-compiling NetHack, if even possible, is much more complicated and far beyond the scope of this article.

Selecting a hints file
The new build system introduced in NetHack 3.6.0 is based on "hints files", which inform the rest of the build system about various things which might differ from one system to another, and which you might wish to customize when building, even if you are making no changes to the actual game.  Things like which directory to install the game's binaries into, which directory to use for storing the game data, which flags to pass to the compiler, and even basic facts like what the compiler on your system is called, are all specified in the hints file.  A hints file is simply a plain text file, formatted like a shell script, that contains hints for the NetHack build system, in the form of setting variables.
You can find a collection of existing hints files in the sys/unix/hints/ directory.  You may find that one of them is closer to what you want than others.  For example, the 'linux' hints file is designed for a single-user install in ~/nh/install; whereas, the 'unix' hints file is designed for a traditional system-wide install in /usr.  Look through the existing hints files and see if you can find one that is a close fit for your needs.

Modifying a hints file
If you need to combine or modify a hints file, here are some useful things to know:

Lines starting with # are comments.  You can thus prepend # to an existing line to comment it out, rendering it ineffective but leaving it there for reference.
There are four main directories that need to be specified: 'HACKDIR', 'SHELLDIR', 'INSTDIR', and 'VARDIR'.  These are often based on a 'PREFIX' directory, which is not itself used directly for anything, but the others are typically located inside of it.
The CHOWN and CHGRP variables should contain the commands used to change ownership and group-ownership of files, respectively.  Setting it to a command that doesn't do anything (such as 'yes' or 'true', as the stock 'linux' hints file does) will result in permissions not being changed, which is typically not what you want except possibly for a single-user install.  If you are modifying the 'linux' hints file to build on a Linux system, you will probably want to change these lines.
The WINSRC, WINOBJ, and WINLIB lines control which window port you will build.  If this is your first time compiling NetHack, it is recommended to start with the TTY port, which is easiest to build successfully.
In 3.7.0, hints/linux tends not to compile, but hints/linux-debug works fine. VARDIR seems to need '/var' to be at the end of the path you choose, or else the game won't start because it can't find the scoreboard. You may also want to remove 'CFLAGS+=-DPANICLOG_FMT2' because it generates tons of warnings.
Running the build setup script
Once you have selected and possibly modified a hints file, you are almost ready to run the setup script.  Run "make fetch-lua".
Then on most platforms, setup is done with the following command:
sys/unix/setup.sh sys/unix/hints/whichever_hints_file_you_are_using
On non-Unix platforms, the setup process may be slightly different.  See the documentation for your platform. The setup script should copy the needed build-system files (e.g., makefiles) into place and modify them as needed.

Windows
For Nethack 3.6 on Windows, it's a good idea to follow the instructions inside sys\winnt\Install.nt. The following assumes that you have your compiler and coreutils from projects such as MinGW and GnuWin32.

Navigate to sys\winnt and run nhsetup.bat.
Navigate to src and edit Makefile.gcc.
Inside the Makefile, you're going to want to edit or check the following things:
Do you want the outputted binary to belong in ..\binary, or somewhere else?
Are you compiling for a specific architecture (x86 or x64)? If so, edit TARGET_CPU.
Do you want Curses window port support? If so, uncomment ADD_CURSES=Y and make sure that you've cloned the PDCurses repository from https://github.com/wmcbrine/PDCurses.
TODO: (Test this, I only wanted the terminal interface) Do you want Qt support? You're going to want to change this option and specify the location of the Qt directory.
On Line 484, are the compiler macros set up correctly? Mine were not, as Chocolatey links the compilers to standard gcc filenames instead of mingw32-gcc.exe. Comment out the #ifndef directive and specify the compilers.
Make with your make program. For me, the invocation was mingw32-make -f Makefile.gcc install. Note that if you don't specify the -f Makefile.gcc option, you'll get an error, as the standard Makefile is for Visual Studio's nmake program.

The following information pertains to an upcoming version (NetHack 3.7.0). If this version is now released, please verify that it is still accurate, then update the page to incorporate this information.

Nethack 3.7 has good support for building, running, and debugging in Visual Studio 2017, 2019, and 2022, including a working solution file. Tools such as MinGW and GnuWin32 are not required. See sys\windows\Install.windows for instructions. After building the project, you may need to rename the "symbols.template" file in the target director to "symbols".
Compiling
At this point, you may be able to just run the 'make' command and get a working build.

Installing
If the build goes well, you can (as root/superuser if necessary, or with sudo) use the 'make install' command to install your newly compiled NetHack.

Creating the system config file
When you try to run your new build, it will complain that there is no syscf file and refuse to do anything until you create that file.  The syscf file is allowed to be empty; it just has to exist.  Simply create an empty file named sysconf in your HACKDIR and nethack will run normally.
Depending on which hints file you used, some permissions may need to be changed before the game can be run as a regular user.

This page may need to be updated for the current version of NetHack.
It may contain text specific to NetHack 3.6.0. Information on this page may be out of date.
Editors: After reviewing this page and making necessary edits, please change the {{nethack-360}} tag to the current version's tag or {{noversion}} as appropriate.