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Installation Guide
User's Guide
Version 5.8.3

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Chapters

- Installing the Binary Release
  - Top of chapter
  - UNIX
  - Windows
- Installation Verification
  - Top of chapter
  - UNIX
  - Windows
- Building and Installing Erlang/OTP
  - Top of chapter
  - Introduction
  - Daily Build and Test
  - Versions Known NOT to Work
  - Required Utilities
  - How to Build and Install Erlang/OTP
  - The Erlang/OTP Documentation
  - Support for SMP (Symmetric Multi Processing)
  - GS (Graphic System)
  - Using HiPE
  - Mac OS X (Darwin)
  - How to Build a Debug Enabled Erlang RunTime System
  - Authors
  - Copyright and License
  - More Information
  - Modifying This Document
- Cross Compiling Erlang/OTP
  - Top of chapter
  - Introduction
  - Build and Install Procedure
  - Currently Used Configuration Variables
  - Copyright and License
  - Modifying This Document
- How to Build Erlang/OTP on Windows
  - Top of chapter
  - Introduction
  - Frequently Asked Questions
  - Tools you Need and Their Environment
  - The Shell Environment
  - Building and Installing
  - Development
  - Final Words
  - Copyright and License
  - Modifying This Document

# 3 Building and Installing Erlang/OTP

Table of Contents

- Introduction
- Daily Build and Test
- Versions Known NOT to Work
- Required Utilities
  - Unpacking
  - Building
    - Building Documentation
    - Building in Git
  - Installing
- How to Build and Install Erlang/OTP
  - Unpacking
  - Configuring
  - Building
  - Installing
  - A Closer Look at the individual Steps
    - Configuring
    - Building
    - Installing
      - Alternative Installation Procedures
  - Symbolic Links in --bindir
  - Pre-built Source Release
  - Building in Git
  - make and $ERL_TOP
- The Erlang/OTP Documentation
  - How to Build the Documentation
    - Build Issues
  - How to Install the Pre-formatted Documentation
- Support for SMP (Symmetric Multi Processing)
- GS (Graphic System)
- Using HiPE
- Mac OS X (Darwin)
- How to Build a Debug Enabled Erlang RunTime System
- Authors
- Copyright and License
- More Information
- Modifying This Document

### 3.1 Introduction

This document describes how to build and install Erlang/OTP-R14B02. You are advised to read the whole document before attempting to build and install Erlang/OTP. You can find more information about Open Source Erlang/OTP at:

http://www.erlang.org/

The source code for Erlang/OTP can also be found in a Git repository:

http://github.com/erlang/otp

Erlang/OTP should be possible to build from source on any Unix system, including Mac OS X. This document describes how to native compile Erlang/OTP on Unix. For detailed instructions on how to

- cross compile Erlang/OTP, see the $ERL_TOP/INSTALL-CROSS.md document.

- build Erlang/OTP on Windows, see the $ERL_TOP/INSTALL-WIN32.md document.

  Binary releases for Windows can be found at http://www.erlang.org/download.html.

Before reading the above mensioned documents you are in any case advised to read this document first, since it covers building Erlang/OTP in general as well as other important information.

### 3.2 Daily Build and Test

At Ericsson we have a "Daily Build and Test" that runs on:

- Solaris 8, 9
  - Sparc32
  - Sparc64
- Solaris 10
  - Sparc32
  - Sparc64
  - x86
- SuSE Linux/GNU 9.4, 10.1
  - x86
- SuSE Linux/GNU 10.0, 10.1
  - x86
  - x86_64
- SuSE Linux/GNU 11.0
  - x86_64
- Gentoo Linux/GNU 1.12.11.1
  - x86
- MontaVista Linux/GNU 4.0.1
  - PowerPC
- FreeBSD 7.1
  - x86
- Mac OS X 10.4.11 (Tiger), 10.5.8 (Leopard), 10.6.0 (Snow Leopard)
  - x86
- Windows XP SP3, 2003, Vista, 7
  - x86

We also have the following "Daily Cross Builds":

- SuSE Linux/GNU 10.1 x86 -> SuSE Linux/GNU 10.1 x86_64
- SuSE Linux/GNU 10.1 x86_64 -> Linux/GNU TILEPro64

and the following "Daily Cross Build Tests":

- SuSE Linux/GNU 10.1 x86_64

### 3.3 Versions Known NOT to Work

- Suse linux 9.1 is shipped with a patched GCC version 3.3.3, having the rpm named gcc-3.3.3-41. That version has a serious optimization bug that makes it unusable for building the Erlang emulator. Please upgrade GCC to a newer version before building on Suse 9.1. Suse Linux Enterprise edition 9 (SLES9) has gcc-3.3.3-43 and is not affected.

- gcc-4.3.0 has a serious optimizer bug. It produces an Erlang emulator that will crash immediately. The bug is supposed to be fixed in gcc-4.3.1.

- FreeBSD had a bug which caused kqueue/poll/select to fail to detect that a writev() on a pipe has been made. This bug should have been fixed in FreeBSD 6.3 and FreeBSD 7.0. NetBSD and DragonFlyBSD probably have or have had the same bug. More information can be found at:

  - http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/kern/sys_pipe.c
  - http://lists.freebsd.org/pipermail/freebsd-arch/2007-September/006790.html

- getcwd() on Solaris 9 can cause an emulator crash. If you have async-threads enabled you can increase the stack size of the async-threads as a temporary workaround. See the +a command-line argument in the documentation of erl(1). Without async-threads the emulator is not as vulnerable to this bug, but if you hit it without async-threads the only workaround available is to enable async-threads and increase the stack size of the async-threads. Sun has however released patches that fixes the issue:

  Problem Description: 6448300 large mnttab can cause stack overrun during Solaris 9 getcwd

  More information can be found at:

  - http://sunsolve.sun.com/search/document.do?assetkey=1-21-112874-40-1&searchclause=6448300
  - http://sunsolve.sun.com/search/document.do?assetkey=1-21-114432-29-1&searchclause=6448300

### 3.4 Required Utilities

These are the tools you will 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 (such as GNU TAR).

#### Building

- GNU make
- gcc -- GNU C compiler
- Perl 5
- GNU m4 -- If HiPE (native code) support is enabled. HiPE can be disabled using --disable-hipe
- 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.
- OpenSSL -- Optional, but needed for building the Erlang/OTP applications ssl and crypto. You need the "development package" of OpenSSL, i.e. including the header files. For building the application ssl the OpenSSL binary command program openssl is also needed. At least version 0.9.7 of OpenSSL is required. Can be downloaded from http://www.openssl.org.
- Sun Java jdk-1.5.0 or higher -- Optional but needed for building the Erlang/OTP application jinterface and parts of ic and orber. Can be downloaded from http://java.sun.com. We have also tested IBM's JDK 1.5.0.
- X Windows -- Optional, but development headers and libraries are needed to build the Erlang/OTP application gs on Unix/Linux.
- sed -- There seem to be some problems with some of the sed version on Solaris. Make sure /bin/sed or /usr/bin/sed is used on the Solaris platform.
- flex -- Optional, headers and libraries are needed to build the flex scanner for the megaco application on Unix/Linux.

Building Documentation

- xsltproc -- XSLT processor. A tool for applying XSLT stylesheets to XML documents. Can be downloaded from http://xmlsoft.org/XSLT/xsltproc2.html.
- fop -- Apache FOP print formatter (requires Java). Can be downloaded from http://xmlgraphics.apache.org/fop.

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.

#### Installing

- An install program that can take multiple file names.

### 3.5 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

Step 1: Start by unpacking the Erlang/OTP distribution file with your GNU compatible TAR program.

    $ gunzip -c otp_src_R14B02.tar.gz | tar xf -

alternatively:

    $ zcat otp_src_R14B02.tar.gz | tar xf -

Step 2: Now cd into the base directory ($ERL_TOP).

    $ cd otp_src_R14B02

#### Configuring

Step 3: On some platforms Perl may behave strangely if certain locales are set, so optionally you may need to set the LANG variable:

    # Bourne shell
    $ LANG=C; export LANG

or

    # C-Shell
    $ setenv LANG C

Step 4: Run the following commands to configure the build:

    $ ./configure  [ options ]

By default, Erlang/OTP will be installed in /usr/local/{bin,lib/erlang}. To instead install in <BaseDir>/{bin,lib/erlang}, use the --prefix=<BaseDir> option.

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

#### Building

Step 5: Build the Erlang/OTP package.

    $ make

#### Installing

Step 6: Install then Erlang/OTP package

    $ make install

#### A Closer Look at the individual Steps

Let us go through them in some detail.

Configuring

Step 4 runs a configuration script 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.
- --{enable,disable}-threads - Thread support (enabled by default if possible)
- --{enable,disable}-smp-support - SMP support (enabled by default if possible)
- --{enable,disable}-kernel-poll - Kernel poll support (enabled by default if possible)
- --{enable,disable}-hipe - HiPE support (enabled by default on supported platforms)
- --enable-darwin-universal - Build universal binaries on darwin i386.
- --enable-darwin-64bit - Build 64-bit binaries on darwin
- --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
- --{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}-dynamic-ssl-lib - Dynamic OpenSSL libraries
- --{enable,disable}-shared-zlib - Shared zlib library
- --with-ssl=PATH - Specify location of OpenSSL include and lib
- --{with,without}-ssl - OpenSSL (without implies that the crypto, ssh, and ssl won't be built)
- --enable-ethread-pre-pentium4-compatibility - Enable compatibility with x86 processors before pentium 4 (back to 486) in the ethread library. If not passed the ethread library (part of the runtime system) will use instructions that first appeared on the pentium 4 processor when building for x86. This option will be automatically enabled if required on the build machine.
- --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 http://www.hpl.hp.com/research/linux/atomic_ops/.

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

Building

Step 5 builds the Erlang/OTP system. On a fast computer, this will take about 5 minutes. After completion of this step, you should have a working Erlang/OTP system which you can try by typing bin/erl. This should start up Erlang/OTP and give you a prompt:

    $ bin/erl
    Erlang R14B02 (erts-5.8.3) [source] [smp:4:4] [rq:4] [async-threads:0] [kernel-poll:false]

    Eshell V5.8.3  (abort with ^G)
    1> _

Installing

Step 6 is optional. It installs Erlang/OTP at a standardized location (if you change your mind about where you wish to install you can rerun step 4, without having to do step 5 again).

Alternative Installation Procedures

- 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.

#### 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.

#### Building in 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. This since 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 the released source.

Other useful information can be found at our github wiki: http://wiki.github.com/erlang/otp

#### 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.

### 3.6 The Erlang/OTP Documentation

#### How to Build the Documentation

    $ 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-R14B02 system in the $PATH.

    $ export PATH=<Erlang/OTP-R14B02 bin dir>:$PATH     # Assuming bash/sh

Build the documentation.

    $ make docs

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>

Build Issues

We have sometimes experienced problems with Sun'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 Pre-formatted Documentation

Pre-formatted html documentation and man pages can be downloaded at http://www.erlang.org/download.html.

For some graphical tools to find the on-line help you have to install the HTML documentation on top of the installed OTP applications, i.e.

    $ cd <ReleaseDir>
    $ gunzip -c otp_html_R14B02.tar.gz | tar xf -

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

    $ cd <ReleaseDir>
    $ gunzip -c otp_man_R14B02.tar.gz | tar xf -

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>.

### 3.7 Support for SMP (Symmetric Multi Processing)

An emulator with SMP support will be built by default on most platforms if a usable POSIX thread library or native Windows threads is found.

You can force building of an SMP emulator, by using ./configure --enable-smp-support. However, if configure does not automatically enable SMP support, the build is very likely to fail.

Use ./configure --disable-smp-support if you for some reason do not want to have the emulator with SMP support built.

If SMP support is enabled, support for threaded I/O will also be turned on (also in the emulator without SMP support).

The erl command will automatically start the SMP emulator if the computer has more than one logical processor. You can force a start of the emulator with SMP support by passing -smp enable as command line arguments to erl, and you can force a start of the emulator without SMP support by passing -smp disable.

### 3.8 GS (Graphic System)

GS now Tcl/Tk 8.4. It will be searched for when starting GS.

### 3.9 Using HiPE

HiPE supports the following system configurations:

- x86: All 32-bit and 64-bit mode processors should work.

  - Linux: Fedora Core is supported. Both 32-bit and 64-bit modes are supported.

    NPTL glibc is strongly preferred, or a LinuxThreads glibc configured for "floating stacks". Old non-floating stacks glibcs have a fundamental problem that makes HiPE support and threads support mutually exclusive.

  - Solaris: Solaris 10 (32-bit and 64-bit) and 9 (32-bit) are supported. The build requires a version of the GNU C compiler (gcc) that has been configured to use the GNU assembler (gas). Sun's x86 assembler is emphatically not supported.

  - FreeBSD: FreeBSD 6.1 and 6.2 in 32-bit and 64-bit modes should work.

  - MacOSX/Darwin: Darwin 9.8.0 in 32-bit mode should work.

- PowerPC: All 32-bit 6xx/7xx(G3)/74xx(G4) processors should work. 32-bit mode on 970 (G5) and POWER5 processors should work.

  - Linux (Yellow Dog) and Mac OSX 10.4 are supported.

- SPARC: All UltraSPARC processors running 32-bit user code should work.

  - Solaris 9 is supported. The build requires a gcc that has been configured to use Sun's assembler and linker. Using the GNU assembler but Sun's linker has been known to cause problems.

  - Linux (Aurora) is supported.

- ARM: ARMv5TE (i.e. XScale) processors should work. Both big-endian and little-endian modes are supported.

  - Linux is supported.

HiPE is automatically enabled on the following systems:

- x86 in 32-bit mode: Linux, Solaris, FreeBSD
- x86 in 64-bit mode: Linux, Solaris, FreeBSD
- PowerPC: Linux, MacOSX
- SPARC: Linux
- ARM: Linux

On other supported systems you need to ./configure --enable-hipe.

If you are running on a platform supporting HiPE and if you have not disabled HiPE, you can compile a module into native code like this from the Erlang shell:

    1> c(Module, native).

or

    1> c(Module, [native|OtherOptions]).

Using the erlc program, write like this:

    $ erlc +native Module.erl

The native code will be placed into the beam file and automatically loaded when the beam file is loaded.

To add hipe options, write like this from the Erlang shell:

    1> c(Module, [native,{hipe,HipeOptions}|MoreOptions]).

Use hipe:help_options/0 to print out the available options.

    1> hipe:help_options().

### 3.10 Mac OS X (Darwin)

We test Mac OS X 10.4.11 (Tiger) and Mac OS X 10.5.x (Leopard) in our daily builds (but only on Intel processors).

Make sure that the command hostname returns a valid fully qualified host name (this is configured in /etc/hostconfig).

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.

Universal 32bit binaries can be built on an Intel Mac using the --enable-darwin-universal configure option. There still may occur problems with certain applications using this option, but the base system should run smoothly.

When building universal binaries on a PowerPC Mac (at least on Tiger), you must point out a suitable SDK that contains universal binaries. For instance, to build universal binaries for Tiger (10.4):

    $ CFLAGS="-isysroot /Developer/SDKs/MacOSX10.4u.sdk" \
    LDFLAGS="-isysroot /Developer/SDKs/MacOSX10.4u.sdk" \
    ./configure --enable-darwin-universal

Also, if you run Leopard, but want to build for Tiger, you must do by setting the MACOSX_DEPLOYMENT_TARGET environmental variable.

    $ export MACOSX_DEPLOYMENT_TARGET=10.4

Experimental support for 64bit x86 darwin binaries can be enabled using the --enable-darwin-64bit configure flag. The 64bit binaries are best built and run on Leopard, but most of the system also works on Tiger (Tiger's 64bit libraries are, however, limited; therefore e.g. odbc, crypto, ssl etc. are not supported in Tiger). 64bit PPC binaries are not supported and we have no plans to add such support (no machines to test on).

Universal binaries and 64bit binaries are mutually exclusive options.

### 3.11 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.

In this directory execute:

    $ make debug FLAVOR=$FLAVOR

where $FLAVOR is either plain or smp. The flavor options will produce a beam.debug and beam.smp.debug executable respectively. The files are installed along side with the normal (opt) versions beam.smp and beam.

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.

    $ make $TYPE FLAVOR=$FLAVOR

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

### 3.12 Authors

Authors are mostly listed in the application's AUTHORS files, that is $ERL_TOP/lib/*/AUTHORS and $ERL_TOP/erts/AUTHORS, not in the individual source files.

### 3.13 Copyright and License

Copyright Ericsson AB 1998-2010. All Rights Reserved.

The contents of this file are subject to the Erlang Public License, Version 1.1, (the "License"); you may not use this file except in compliance with the License. You should have received a copy of the Erlang Public License along with this software. If not, it can be retrieved online at http://www.erlang.org/.

Software distributed under the License is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the specific language governing rights and limitations under the License.

### 3.14 More Information

More information can be found at http://www.erlang.org.

### 3.15 Modifying This Document

Before modifying this document you need to have a look at the $ERL_TOP/README.md.txt document.