Erlang -- Building and Installing Erlang/OTP

Installation Guide

User's Guide

Version 12.0

- User's Guide
- PDF
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### Chapters

- Installing the Binary Release
  - Top of chapter
  - Windows
- Building and Installing Erlang/OTP
  - Top of chapter
  - Introduction
  - Required Utilities
  - Optional Utilities
  - How to Build and Install Erlang/OTP
  - Advanced configuration and build of Erlang/OTP
- Cross Compiling Erlang/OTP
  - Top of chapter
  - Introduction
  - Build and Install Procedure
  - Building and Installing the Documentation
  - Testing the cross compiled system
  - Currently Used Configuration Variables
- How to Build Erlang/OTP on Windows
  - Top of chapter
  - Introduction
  - Short Version
  - Tools you Need and Their Environment
  - The Shell Environment
  - Building and Installing
  - Development
  - Frequently Asked Questions
- Patching OTP Applications
  - Top of chapter
  - Introduction
  - Prerequisites
  - Using otp_patch_apply
  - Sanity check

# 2 Building and Installing Erlang/OTP

### 2.1 Introduction

This document describes how to build and install Erlang/OTP-24. Erlang/OTP should be possible to build from source on any Unix/Linux system, including OS X. You are advised to read the whole document before attempting to build and install Erlang/OTP.

The source code can be downloaded from the official site of Erlang/OTP or GitHub.

- http://www.erlang.org
- https://github.com/erlang/otp

### 2.2 Required Utilities

These are the tools you need in order to unpack and build Erlang/OTP.

#### Unpacking

- GNU unzip, or a modern uncompress.
- A TAR program that understands the GNU TAR format for long filenames.

#### Building

- GNU make
- Compiler -- GNU C Compiler, gcc or the C compiler frontend for LLVM, clang.
- Perl 5
- GNU m4
- ncurses, termcap, or termlib -- The development headers and libraries are needed, often known as ncurses-devel. Use --without-termcap to build without any of these libraries. Note that in this case only the old shell (without any line editing) can be used.
- sed -- Stream Editor for basic text transformation.

##### Building in Git

- GNU autoconf of at least version 2.59. Note that autoconf is not needed when building an unmodified version of the released source.

##### Building on OS X

- Xcode -- Download and install via the Mac App Store. Read about Building on a Mac before proceeding.

#### Installing

- An install program that can take multiple file names.

### 2.3 Optional Utilities

Some applications are automatically skipped if the dependencies aren't met. Here is a list of utilities needed for those applications. You will also find the utilities needed for building the documentation.

#### Building

- OpenSSL -- The opensource toolkit for Secure Socket Layer and Transport Layer Security. Required for building the application crypto. Further, ssl and ssh require a working crypto application and will also be skipped if OpenSSL is missing. The public_key application is available without crypto, but the functionality will be very limited.

  The development package of OpenSSL including the header files are needed as well as the binary command program openssl. At least version 0.9.8 of OpenSSL is required. Read more and download from http://www.openssl.org.

- Oracle Java SE JDK -- The Java Development Kit (Standard Edition). Required for building the application jinterface. At least version 1.6.0 of the JDK is required.

  Download from http://www.oracle.com/technetwork/java/javase/downloads. We have also tested with IBM's JDK 1.6.0.

- flex -- Headers and libraries are needed to build the flex scanner for the megaco application on Unix/Linux.

- wxWidgets -- Toolkit for GUI applications. Required for building the wx application. At least version 3.0 of wxWidgets is required.

  Download from http://sourceforge.net/projects/wxwindows/files/3.0.0/ or get it from GitHub: https://github.com/wxWidgets/wxWidgets

  Further instructions on wxWidgets, read Building with wxErlang.

#### Building Documentation

- xsltproc -- A command line XSLT processor.

  A tool for applying XSLT stylesheets to XML documents. Download xsltproc from http://xmlsoft.org/XSLT/xsltproc2.html.

- fop -- Apache FOP print formatter (requires Java). Can be downloaded from http://xmlgraphics.apache.org/fop.

### 2.4 How to Build and Install Erlang/OTP

The following instructions are for building the released source tar ball.

The variable $ERL_TOP will be mentioned a lot of times. It refers to the top directory in the source tree. More information about $ERL_TOP can be found in the make and $ERL_TOP section below. If you are building in git you probably want to take a look at the Building in Git section below before proceeding.

#### Unpacking

Start by unpacking the Erlang/OTP distribution file with your GNU compatible TAR program.

    $ tar -zxf otp_src_24.0.tar.gz    # Assuming bash/sh

Now change directory into the base directory and set the $ERL_TOP variable.

    $ cd otp_src_24.0
    $ export ERL_TOP=`pwd`    # Assuming bash/sh

#### Configuring

Run the following commands to configure the build:

    $ ./configure [ options ]

Note

If you are building Erlang/OTP from git you will need to run ./otp_build autoconf to generate the configure scripts.

By default, Erlang/OTP release will be installed in /usr/local/{bin,lib/erlang}. If you for instance don't have the permission to install in the standard location, you can install Erlang/OTP somewhere else. For example, to install in /opt/erlang/24.0/{bin,lib/erlang}, use the --prefix=/opt/erlang/24.0 option.

On some platforms Perl may behave strangely if certain locales are set. If you get errors when building, try setting the LANG variable:

    $ export LANG=C   # Assuming bash/sh

#### Building

Build the Erlang/OTP release.

    $ make

#### Testing

Before installation you should test whether your build is working properly by running our smoke test. The smoke test is a subset of the complete Erlang/OTP test suites. First you will need to build and release the test suites.

    $ make release_tests

This creates an additional folder in $ERL_TOP/release called tests. Now, it's time to start the smoke test.

    $ cd release/tests/test_server
    $ $ERL_TOP/bin/erl -s ts install -s ts smoke_test batch -s init stop

To verify that everything is ok you should open $ERL_TOP/release/tests/test_server/index.html in your web browser and make sure that there are zero failed test cases.

Note

On builds without crypto, ssl and ssh there is a failed test case for undefined functions. Verify that the failed test case log only shows calls to skipped applications.

#### Installing

You are now ready to install the Erlang/OTP release! The following command will install the release on your system.

    $ make install

#### Running

You should now have a working release of Erlang/OTP! Jump to System Principles for instructions on running Erlang/OTP.

#### How to Build the Documentation

Make sure you're in the top directory in the source tree.

    $ cd $ERL_TOP

If you have just built Erlang/OTP in the current source tree, you have already ran configure and do not need to do this again; otherwise, run configure.

    $ ./configure [Configure Args]

When building the documentation you need a full Erlang/OTP-24.0 system in the $PATH.

    $ export PATH=$ERL_TOP/bin:$PATH     # Assuming bash/sh

For the FOP print formatter, two steps must be taken:

- Adding the location of your installation of fop in $FOP_HOME.

      $ export FOP_HOME=/path/to/fop/dir # Assuming bash/sh

- Adding the fop script (in $FOP_HOME) to your $PATH, either by adding $FOP_HOME to $PATH, or by copying the fop script to a directory already in your $PATH.

Build the documentation.

    $ make docs

It is possible to limit which types of documentation is build by passing the DOC_TARGETS environment variable to make docs. The currently available types are: html, pdf, man and chunks. Example:

    $ make docs DOC_TARGETS=chunks

##### Build Issues

We have sometimes experienced problems with Oracle's java running out of memory when running fop. Increasing the amount of memory available as follows has in our case solved the problem.

    $ export FOP_OPTS="-Xmx<Installed amount of RAM in MB>m"

More information can be found at

- http://xmlgraphics.apache.org/fop/0.95/running.html#memory.

#### How to Install the Documentation

The documentation can be installed either using the install-docs target, or using the release_docs target.

- If you have installed Erlang/OTP using the install target, install the documentation using the install-docs target. Install locations determined by configure will be used. $DESTDIR can be used the same way as when doing make install.

      $ make install-docs

- If you have installed Erlang/OTP using the release target, install the documentation using the release_docs target. You typically want to use the same RELEASE_ROOT as when invoking make release.

      $ make release_docs RELEASE_ROOT=<release dir>

It is possible to limit which types of documentation is released using the same DOC_TARGETS environment variable as when building documentation.

#### Accessing the Documentation

After installation you can access the documentation by

- Reading man pages. Make sure that erl is referring to the installed version. For example /usr/local/bin/erl. Try viewing at the man page for Mnesia

      $ erl -man mnesia

- Browsing the html pages by loading the page /usr/local/lib/erlang/doc/erlang/index.html or <BaseDir>/lib/erlang/doc/erlang/index.html if the prefix option has been used.

- Read the embedded documentation by using the built-in shell functions h/1,2,3 or ht/1,2,3.

#### How to Install the Pre-formatted Documentation

Pre-formatted html documentation and man pages can be downloaded from

- http://www.erlang.org/download.html.

Extract the html archive in the installation directory.

    $ cd <ReleaseDir>
    $ tar -zxf otp_html_24.0.tar.gz

For erl -man <page> to work the Unix manual pages have to be installed in the same way, i.e.

    $ cd <ReleaseDir>
    $ tar -zxf otp_man_24.0.tar.gz

Where <ReleaseDir> is

- <PrefixDir>/lib/erlang if you have installed Erlang/OTP using make install.
- $DESTDIR<PrefixDir>/lib/erlang if you have installed Erlang/OTP using make install DESTDIR=<TmpInstallDir>.
- RELEASE_ROOT if you have installed using make release RELEASE_ROOT=<ReleaseDir>.

### 2.5 Advanced configuration and build of Erlang/OTP

If you want to tailor your Erlang/OTP build and installation, please read on for detailed information about the individual steps.

#### make and $ERL_TOP

All the makefiles in the entire directory tree use the environment variable ERL_TOP to find the absolute path of the installation. The configure script will figure this out and set it in the top level Makefile (which, when building, it will pass on). However, when developing it is sometimes convenient to be able to run make in a subdirectory. To do this you must set the ERL_TOP variable before you run make.

For example, assume your GNU make program is called make and you want to rebuild the application STDLIB, then you could do:

    $ cd lib/stdlib; env ERL_TOP=<Dir> make

where <Dir> would be what you find ERL_TOP is set to in the top level Makefile.

#### otp_build vs configure/make

Building Erlang/OTP can be done either by using the $ERL_TOP/otp_build script, or by invoking $ERL_TOP/configure and make directly. Building using otp_build is easier since it involves fewer steps, but the otp_build build procedure is not as flexible as the configure/make build procedure. The binary releases for Windows that we deliver are built using otp_build.

#### Configuring

The configure script is created by the GNU autoconf utility, which checks for system specific features and then creates a number of makefiles.

The configure script allows you to customize a number of parameters; type ./configure --help or ./configure --help=recursive for details. ./configure --help=recursive will give help for all configure scripts in all applications.

One of the things you can specify is where Erlang/OTP should be installed. By default Erlang/OTP will be installed in /usr/local/{bin,lib/erlang}. To keep the same structure but install in a different place, <Dir> say, use the --prefix argument like this: ./configure --prefix=<Dir>.

Some of the available configure options are:

- --prefix=PATH - Specify installation prefix.
- --disable-parallel-configure - Disable parallel execution of configure scripts (parallel execution is enabled by default)
- --{enable,disable}-jit - Force enabling or disabling of the JIT.
- --{enable,disable}-kernel-poll - Kernel poll support (enabled by default if possible)
- --enable-m64-build - Build 64-bit binaries using the -m64 flag to (g)cc
- --enable-m32-build - Build 32-bit binaries using the -m32 flag to (g)cc
- --{enable,disable}-pie - Build position independent executable binaries.
- --with-assumed-cache-line-size=SIZE - Set assumed cache-line size in bytes. Default is 64. Valid values are powers of two between and including 16 and 8192. The runtime system use this value in order to try to avoid false sharing. A too large value wastes memory. A to small value will increase the amount of false sharing.
- --{with,without}-termcap - termcap (without implies that only the old Erlang shell can be used)
- --with-javac=JAVAC - Specify Java compiler to use
- --{with,without}-javac - Java compiler (without implies that the jinterface application won't be built)
- --{enable,disable}-builtin-zlib - Use the built-in source for zlib.
- --{enable,disable}-dynamic-ssl-lib - Enable or disable dynamic OpenSSL libraries when linking the crypto NIF. By default dynamic linking is done unless it does not work or is if it is a Windows system.
- --{with,without}-ssl - OpenSSL (without implies that the crypto, ssh, and ssl won't be built)
- --with-ssl=PATH - Specify base location of OpenSSL include and lib directories.
- --with-ssl-incl=PATH - Specify base location of OpenSSL include directory (if different than base location specified by --with-ssl=PATH).
- --with-ssl-zlib=PATH - Path to static zlib library to link the crypto NIF with. This zlib library is most often not necessary but might be needed in order to link the NIF in some cases.
- --with-ssl-lib-subdir=RELATIVE_PATH - Specify extra OpenSSL lib sub-directory to search in (relative to base directory).
- --with-ssl-rpath=yes|no|PATHS - Runtime library path for OpenSSL. Default is yes, which equates to a number of standard locations. If no, then no runtime library paths will be used. Anything else should be a comma or colon separated list of paths.
- --with-libatomic_ops=PATH - Use the libatomic_ops library for atomic memory accesses. If configure should inform you about no native atomic implementation available, you typically want to try using the libatomic_ops library. It can be downloaded from https://github.com/ivmai/libatomic_ops/.
- --disable-smp-require-native-atomics - By default configure will fail if an SMP runtime system is about to be built, and no implementation for native atomic memory accesses can be found. If this happens, you are encouraged to find a native atomic implementation that can be used, e.g., using libatomic_ops, but by passing --disable-smp-require-native-atomics you can build using a fallback implementation based on mutexes or spinlocks. Performance of the SMP runtime system will however suffer immensely without an implementation for native atomic memory accesses.
- --enable-static-{nifs,drivers} - To allow usage of nifs and drivers on OSs that do not support dynamic linking of libraries it is possible to statically link nifs and drivers with the main Erlang VM binary. This is done by passing a comma separated list to the archives that you want to statically link. e.g. --enable-static-nifs=/home/$USER/my_nif.a. The path has to be absolute and the name of the archive has to be the same as the module, i.e. my_nif in the example above. This is also true for drivers, but then it is the driver name that has to be the same as the filename. You also have to define STATIC_ERLANG_{NIF,DRIVER} when compiling the .o files for the nif/driver. If your nif/driver depends on some other dynamic library, you now have to link that to the Erlang VM binary. This is easily achieved by passing LIBS=-llibname to configure.
- --without-$app - By default all applications in Erlang/OTP will be included in a release. If this is not wanted it is possible to specify that Erlang/OTP should be compiled without one or more applications, i.e. --without-wx. There is no automatic dependency handling between applications. If you disable an application that another application depends on, you also have to disable the dependant application.
- --enable-gettimeofday-as-os-system-time - Force usage of gettimeofday() for OS system time.
- --enable-prefer-elapsed-monotonic-time-during-suspend - Prefer an OS monotonic time source with elapsed time during suspend.
- --disable-prefer-elapsed-monotonic-time-during-suspend - Do not prefer an OS monotonic time source with elapsed time during suspend.
- --with-clock-resolution=high|low - Try to find clock sources for OS system time, and OS monotonic time with higher or lower resolution than chosen by default. Note that both alternatives may have a negative impact on the performance and scalability compared to the default clock sources chosen.
- --disable-saved-compile-time - Disable saving of compile date and time in the emulator binary.

If you or your system has special requirements please read the Makefile for additional configuration information.

##### Atomic Memory Operations and the VM

The VM with SMP support makes quite a heavy use of atomic memory operations. An implementation providing native atomic memory operations is therefore very important when building Erlang/OTP. By default the VM will refuse to build if native atomic memory operations are not available.

Erlang/OTP itself provides implementations of native atomic memory operations that can be used when compiling with a gcc compatible compiler for 32/64-bit x86, 32/64-bit SPARC V9, 32-bit PowerPC, or 32-bit Tile. When compiling with a gcc compatible compiler for other architectures, the VM may be able to make use of native atomic operations using the __atomic_* builtins (may be available when using a gcc of at least version 4.7) and/or using the __sync_* builtins (may be available when using a gcc of at least version 4.1). If only the gcc's __sync_* builtins are available, the performance will suffer. Such a configuration should only be used as a last resort. When compiling on Windows using a MicroSoft Visual C++ compiler native atomic memory operations are provided by Windows APIs.

Native atomic implementation in the order preferred:

1. The implementation provided by Erlang/OTP.
2. The API provided by Windows.
3. The implementation based on the gcc __atomic_* builtins.
4. If none of the above are available for your architecture/compiler, you are recommended to build and install libatomic_ops before building Erlang/OTP. The libatomic_ops library provides native atomic memory operations for a variety of architectures and compilers. When building Erlang/OTP you need to inform the build system of where the libatomic_ops library is installed using the --with-libatomic_ops=PATH configure switch.
5. As a last resort, the implementation solely based on the gcc __sync_* builtins. This will however cause lots of expensive and unnecessary memory barrier instructions to be issued. That is, performance will suffer. The configure script will warn at the end of its execution if it cannot find any other alternative than this.

#### Building

Building Erlang/OTP on a relatively fast computer takes approximately 5 minutes. To speed it up, you can utilize parallel make with the -j<num_jobs> option.

    $ export MAKEFLAGS=-j8    # Assuming bash/sh
    $ make

If you've upgraded the source with a patch you may need to clean up from previous builds before the new build. Make sure to read the Pre-built Source Release section below before doing a make clean.

##### Within Git

When building in a Git working directory you also have to have a GNU autoconf of at least version 2.59 on your system, because you need to generate the configure scripts before you can start building.

The configure scripts are generated by invoking ./otp_build autoconf in the $ERL_TOP directory. The configure scripts also have to be regenerated when a configure.in or aclocal.m4 file has been modified. Note that when checking out a branch a configure.in or aclocal.m4 file may change content, and you may therefore have to regenerate the configure scripts when checking out a branch. Regenerated configure scripts imply that you have to run configure and build again.

Note

Running ./otp_build autoconf is not needed when building an unmodified version of the released source.

Other useful information can be found at our GitHub wiki:

- https://github.com/erlang/otp/wiki

##### OS X (Darwin)

Make sure that the command hostname returns a valid fully qualified host name (this is configured in /etc/hostconfig). Otherwise you might experience problems when running distributed systems.

If you develop linked-in drivers (shared library) you need to link using gcc and the flags -bundle -flat_namespace -undefined suppress. You also include -fno-common in CFLAGS when compiling. Use .so as the library suffix.

If you have Xcode 4.3, or later, you will also need to download "Command Line Tools" via the Downloads preference pane in Xcode.

##### Building with wxErlang

If you want to build the wx application, you will need to get wxWidgets-3.0 (wxWidgets-3.0.3.tar.bz2 from https://github.com/wxWidgets/wxWidgets/releases/download/v3.0.3/wxWidgets-3.0.3.tar.bz2) or get it from github with bug fixes:

    $ git clone --branch WX_3_0_BRANCH git@github.com:wxWidgets/wxWidgets.git

The wxWidgets-3.1 version should also work if 2.8 compatibility is enabled, add --enable-compat28 to configure commands below.

Configure and build wxWidgets (shared library on linux):

    $ ./configure --prefix=/usr/local
    $ make && sudo make install
    $ export PATH=/usr/local/bin:$PATH

Configure and build wxWidgets (static library on linux):

    $ export CFLAGS=-fPIC
    $ export CXXFLAGS=-fPIC
    $ ./configure --prefix=/usr/local --disable-shared
    $ make && sudo make install
    $ export PATH=/usr/local/bin:$PATH

Configure and build wxWidgets (on Mavericks - 10.9):

    $ ./configure --with-cocoa --prefix=/usr/local
    or without support for old versions and with static libs
    $ ./configure --with-cocoa --prefix=/usr/local --with-macosx-version-min=10.9 --disable-shared
    $ make
    $ sudo make install
    $ export PATH=/usr/local/bin:$PATH

Check that you got the correct wx-config

    $ which wx-config && wx-config --version-full

Build Erlang/OTP

    $ export PATH=/usr/local/bin:$PATH
    $ cd $ERL_TOP
    $ ./configure
    $ make
    $ sudo make install

##### Pre-built Source Release

The source release is delivered with a lot of platform independent build results already pre-built. If you want to remove these pre-built files, invoke ./otp_build remove_prebuilt_files from the $ERL_TOP directory. After you have done this, you can build exactly the same way as before, but the build process will take a much longer time.

Warning

Doing make clean in an arbitrary directory of the source tree, may remove files needed for bootstrapping the build.

Doing ./otp_build save_bootstrap from the $ERL_TOP directory before doing make clean will ensure that it will be possible to build after doing make clean. ./otp_build save_bootstrap will be invoked automatically when make is invoked from $ERL_TOP with either the clean target, or the default target. It is also automatically invoked if ./otp_build remove_prebuilt_files is invoked.

If you need to verify the bootstrap beam files match the provided source files, use ./otp_build update_primary to create a new commit that contains differences, if any exist.

##### How to Build a Debug Enabled Erlang RunTime System

After completing all the normal building steps described above a debug enabled runtime system can be built. To do this you have to change directory to $ERL_TOP/erts/emulator and execute:

    $ (cd $ERL_TOP/erts/emulator && make debug)

This will produce a beam.smp.debug executable. The file are installed along side with the normal (opt) version beam.smp.

To start the debug enabled runtime system execute:

    $ $ERL_TOP/bin/cerl -debug

The debug enabled runtime system features lock violation checking, assert checking and various sanity checks to help a developer ensure correctness. Some of these features can be enabled on a normal beam using appropriate configure options.

There are other types of runtime systems that can be built as well using the similar steps just described.

    $ (cd $ERL_TOP/erts/emulator && make $TYPE)

where $TYPE is opt, gcov, gprof, debug, valgrind, asan or lcnt. These different beam types are useful for debugging and profiling purposes.

#### Installing

- Staged install using DESTDIR. You can perform the install phase in a temporary directory and later move the installation into its correct location by use of the DESTDIR variable:

      $ make DESTDIR=<tmp install dir> install

  The installation will be created in a location prefixed by $DESTDIR. It can, however, not be run from there. It needs to be moved into the correct location before it can be run. If DESTDIR have not been set but INSTALL_PREFIX has been set, DESTDIR will be set to INSTALL_PREFIX. Note that INSTALL_PREFIX in pre R13B04 was buggy and behaved as EXTRA_PREFIX (see below). There are lots of areas of use for an installation procedure using DESTDIR, e.g. when creating a package, cross compiling, etc. Here is an example where the installation should be located under /opt/local:

      $ ./configure --prefix=/opt/local
      $ make
      $ make DESTDIR=/tmp/erlang-build install
      $ cd /tmp/erlang-build/opt/local
      $     # gnu-tar is used in this example
      $ tar -zcf /home/me/my-erlang-build.tgz *
      $ su -
      Password: *****
      $ cd /opt/local
      $ tar -zxf /home/me/my-erlang-build.tgz

- Install using the release target. Instead of doing make install you can create the installation in whatever directory you like using the release target and run the Install script yourself. RELEASE_ROOT is used for specifying the directory where the installation should be created. This is what by default ends up under /usr/local/lib/erlang if you do the install using make install. All installation paths provided in the configure phase are ignored, as well as DESTDIR, and INSTALL_PREFIX. If you want links from a specific bin directory to the installation you have to set those up yourself. An example where Erlang/OTP should be located at /home/me/OTP:

      $ ./configure
      $ make
      $ make RELEASE_ROOT=/home/me/OTP release
      $ cd /home/me/OTP
      $ ./Install -minimal /home/me/OTP
      $ mkdir -p /home/me/bin
      $ cd /home/me/bin
      $ ln -s /home/me/OTP/bin/erl erl
      $ ln -s /home/me/OTP/bin/erlc erlc
      $ ln -s /home/me/OTP/bin/escript escript
      ...

  The Install script should currently be invoked as follows in the directory where it resides (the top directory):

      $ ./Install [-cross] [-minimal|-sasl] <ERL_ROOT>

  where:

  - -minimal Creates an installation that starts up a minimal amount of applications, i.e., only kernel and stdlib are started. The minimal system is normally enough, and is what make install uses.
  - -sasl Creates an installation that also starts up the sasl application.
  - -cross For cross compilation. Informs the install script that it is run on the build machine.
  - <ERL_ROOT> - The absolute path to the Erlang installation to use at run time. This is often the same as the current working directory, but does not have to be. It can follow any other path through the file system to the same directory.

  If neither -minimal, nor -sasl is passed as argument you will be prompted.

- Test install using EXTRA_PREFIX. The content of the EXTRA_PREFIX variable will prefix all installation paths when doing make install. Note that EXTRA_PREFIX is similar to DESTDIR, but it does not have the same effect as DESTDIR. The installation can and have to be run from the location specified by EXTRA_PREFIX. That is, it can be useful if you want to try the system out, running test suites, etc, before doing the real install without EXTRA_PREFIX.

##### Symbolic Links in --bindir

When doing make install and the default installation prefix is used, relative symbolic links will be created from /usr/local/bin to all public Erlang/OTP executables in /usr/local/lib/erlang/bin. The installation phase will try to create relative symbolic links as long as --bindir and the Erlang bin directory, located under --libdir, both have --exec-prefix as prefix. Where --exec-prefix defaults to --prefix. --prefix, --exec-prefix, --bindir, and --libdir are all arguments that can be passed to configure. One can force relative, or absolute links by passing BINDIR_SYMLINKS=relative|absolute as arguments to make during the install phase. Note that such a request might cause a failure if the request cannot be satisfied.

#### Running

#### Erlang/OTP test architectures

Erlang/OTP are currently tested on the following hardware and Opererating systems. This is not an exhaustive list, but we try to keep it as up to date as possible.

Architecture

- x86, x86-64
- Aarch32, Aarch64
- powerpc, powerpc64le

Operating System

- Fedora 31
- FreeBSD
- macOS 10.4 - 11.2
- MontaVista 4
- NetBSD
- OpenBSD
- SLES 10, 11, 12
- SunOS 5.11
- Ubuntu 10.04 - 20.04
- Windows 10, Windows Server 2019