openmpi/HACKING

Overview
========

This file is here for those who are building/exploring OMPI in its
source code form, most likely through a developer's tree (i.e., a SVN
checkout).


Use of GNU Autoconf, Automake, and Libtool
==========================================

If you are building OMPI/MPI from a developer's tree, you must first
use fairly recent versions of the GNU tools Autoconf, Automake, and
Libtool.  As of this writing, you need at least Autoconf v2.58,
Automake v1.7 (or better), and Libtool v1.5.  You can check what
versions you have installed with the following:

shell$ autoconf --version
shell$ automake --version
shell$ libtool --version

If you need newer versions, you are *strongly* encouraged to heed the
following advice:

NOTE: On MacOS/X, the default "libtool" program is different than the
      GNU libtool.  You must download and install the GNU version.

1. Unless your OS distribution has easy-to-use binary installations,
   the sources can be can be downloaded from:

        ftp://ftp.gnu.org/gnu/autoconf/
        ftp://ftp.gnu.org/gnu/automake/
        ftp://ftp.gnu.org/gnu/libtool/

2. Build and install the tools in the following order:

   2a. Autoconf
   2b. Automake
   2c. Libtool

3. You MUST install all three tools into the same prefix directory.
   These three tools are somewhat inter-related, and if they're going
   to be used together, they MUST share a common installation prefix.

   3a. It is *strongly* encouraged that you do not install your new
       versions over the OS-installed versions.  This could cause
       other things on your system to break.  Instead, install into
       $HOME/local, or /usr/local, or wherever else you tend to
       install "local" kinds of software.
   3b. In doing so, be sure to prefix your $path with the directory
       where they are installed.  For example, if you install into
       $HOME/local, you may want to edit your shell startup file
       (.bashrc, .cshrc, .tcshrc, etc.) to have something like:

          # For bash/sh:
          export PATH=$HOME/local/bin:$PATH
          # For csh/tcsh:
          set path = ($HOME/local/bin $path)

   3c. Ensure to set your $path *BEFORE* you configure/build/install
       the three packages.

4. All three packages require two simple commands to build and
   install (where PREFIX is the prefix discussed in 3, above).

      shell$ cd autoconf-2.58
      shell$ ./configure --prefix=PREFIX
      shell$ make all install

      --> if on csh or tcsh, run the "rehash" command

      shell$ cd ../automake-1.7
      shell$ ./configure --prefix=PREFIX
      shell$ make all install

      shell$ cd ../libtool-1.5
      shell$ ./configure --prefix=PREFIX
      shell$ make all install

      --> if on csh or tcsh, run the "rehash" command

   Autoconf and Automake build and install very quickly; Libtool will
   take a minute or two.

5. You can now run OMPI's top-level "autogen.sh" script.  This script
   will invoke the GNU Autoconf, Automake, and Libtool commands in the
   proper order and setup to run OMPI's top-level "configure" script.

   Running autogen.sh may take several minutes.  It's not very
   exciting to watch.  :-)

   5a. You generally need to run autogen.sh whenever the file
       "configure.ac" changes, or any files in the config/ directory
       change (the config/ directory is where a lot of "include" files
       for OMPI's configure script live).

   5b. You do *NOT* need to re-run autogen.sh if you modify a
       Makefile.am.

   5c. Note that "autogen.sh" automatically traverses the entire OMPI
       tree, running the GNU tools in all MCA modules.  This is not
       always necessary.  As you become more familiar with the OMPI
       sources, you will come to understand the when you only need to
       re-generate the top-level configure script, and when you need
       to re-generate *all* configure scripts (it's complicated -- not
       described here -- when in doubt, do them all).

       If you only need to re-generate the top-level configure script,
       you can run:

          shell$ autogen.sh -l

       (i.e., "local" mode) which will prevent autogen.sh from
       traversing all the MCA modules.

   5d. Similarly, if you only need to regenerate the configure script
       in a since MCA module directory, cd into that module's
       directory and run autogen.sh in there directly.

          shell$ cd src/mca/pml/teg
          shell$ ../../../../autogen.sh