README

===========================================================================
                          OpenSource Erlang/OTP 
===========================================================================

Please read the whole file before attempting to build and install Erlang.
You can find more information about Open Source Erlang at:

    http://www.erlang.org/

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

    http://github.com/erlang/otp

%CopyrightBegin%

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.

%CopyrightEnd%

Portability
-----------

Erlang/OTP should be possible to build from source on any Unix
system, including Mac OS X.

Instructions for building from source on Windows are in the file README.win32.
Binary releases for Windows can be found at http://www.erlang.org/

At Ericsson we have a "Daily Build and Test" that runs on:
 
    Operating system        Versions
    -----------------------------------------------------------
    Solaris/Sparc32         8, 9, 10
    Solaris/Sparc64         10
    Solaris/x86             10
    Linux/Suse x86          9.4, 10.1
    Linux/Suse x86_64       10.0, 10.1, 11.0
    FreeBSD x86             7.1
    Mac OS X/Intel          10.4.11 (Tiger), 10.5.8 (Leopard)
    Windows                 XP SP3, 2003, Vista

We have also done some testing on Mac OS 10.6.0 (Snow Leopard).

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 isn't 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

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).

Compiling

 * GNU make
 * GNU C compiler
 * Perl 5
 * GNU m4 -- If hipe (native code) support is enabled.
 * ncurses (or 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. 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.
 * Sun Java jdk-1.5.0 or higher -- Optional but needed for building the
   Erlang/OTP application 'jinterface' and parts of 'ic' and 'orber'. 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.

Installing

 * An 'install' program that can take multiple file names.

How to build and install Erlang/OTP
-----------------------------------

If you are building in a Git repository, see

  http://wiki.github.com/erlang/otp

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

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

    $ gunzip -c otp_src_R13B03.tar.gz | tar xf -
    $ zcat otp_src_R13B03.tar.gz | tar xf -

Step 2: Now cd into the base directory.

    $ cd otp_src_R13B03

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,man/man1}.
To instead install in <BaseDir>/{bin,lib/erlang,man/man1}, 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. Do a "make clean"; see
"Caveats" below.

Step 5: Build the Erlang/OTP package.

    $ make

Step 6: Install then Erlang/OTP package

    $ make install

Let's go through them in some detail:

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" for details.

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,man/man1};
to keep the same structure but install in a different place, <Dir> say,
use the --prefix argument like this:
"./configure --prefix=<Dir>".

This step will also configure any additional libraries unpacked in step 3
(if you didn't add any of the extra libraries configure will issue a warning
saying that there is no configuration information in lib; this warning can
safely be ignored).

You can also specify where the OpenSSL include and library files are
located, or alternatively disable the use of SSL and Crypto.
(The details can be found by typing './configure --help'.)

Other options are:

    --enable-smp-support    See the next section.

    --disable-smp-support   See the next section.

    --disable-threads       Disable support for threaded I/O;
                            this option also disables building of the SMP
                            emulator. (See the next section.)

    --enable-threads        Enable support for threaded I/O.
                            (This is the default if SMP support is enabled.
                            See the next section.)

    --disable-hipe          Disable HiPE (High-Performance Erlang).
                            HiPE will automatically be enabled on supported
                            platforms.

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.

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
    $ mkdir /tmp/erlang-build
    $ 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
* Test install using EXTRA_PREFIX. Note that EXTRA_PREFIX is similar to
  DESTDIR, but it does not have the same effect as DESTDIR. The EXTRA_PREFIX
  variable will prefix all installation paths, and the installation can and
  have to be run from there. 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.
* Install using the `release' target. Instead of doing `make install' you can
  creat 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:
    `./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.
    -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.

When doing `make install' and the default installation prefix is used, relative
symbolic links will be created from /usr/local/bin to all public executables in
the Erlang installation. 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 however 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.

The source tree 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.

NOTE: 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 or your system has special requirements please read the
Makefile for additional configuration information.

Cross compiling Erlang/OTP
--------------------------
The support for cross compiling Erlang/OTP is in its early stage of
development, and should be considered as experimental. For more
information see: $ERL_TOP/xcomp/README

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, lcnt. These
different beam types are useful for debugging and profiling purposes.


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 doesn't
automatically enable SMP support, the build is very likely to fail.

Use "./configure --disable-smp-support" if you for some reason don't
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'.

How to install the Erlang/OTP documentation
-------------------------------------------

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 <PrefixDir>/lib/erlang
    $ gunzip -c otp_html_R<XY>B-<Z>.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 <PrefixDir>/lib/erlang
    $gunzip -c otp_man_R<XY>B-<Z>.tar.gz | tar xf -


GS (Graphic System)
-------------------

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

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 and Linux (Aurora) are supported.

    On Solaris 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.

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().

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.

Make and the variable "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.

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.


More Information
----------------

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