</head>
<body>
-<h1>Porting <acronym>deal.II</acronym> to new systems</h1>
-
-<p> Attention: before starting a port to a new system, check
-the <a href="readme.html">readme file</a> for your system.</p>
-
-<h2>Compiler flags</h2>
-
-A configuration by setting the <TT>CXXFLAGS</TT> variable will soon be
-supported.
-
-<h2>Configuration file</h2>
-
-<p>Configurations must be done in the file <TT>configure.in</TT> of
-the root directory of <acronym>deal.II</acronym>. At the end, look for
-a section of the structure
-<pre>
-case "$target" in
- *-linux*) ...;;
- *-aix*) ...;;
-esac
-
-case "$target" in
- alpha*-linux*) ...;;
-esac
-</pre>
-The first case block allows you to adjust parameters for a certain
-operating system, the second for an operating system/machine
-configuration.</p>
-
-<h3>Enable/disable configured options</h3>
-
-<p>Some of the features of the library are turned on and off by
-<TT>--enable-xxx</TT> and <TT>--with-xxx=yyy</TT> options to
-configure. These user-supplied parameters can be changed by modifying
-related variables: for example, to turn off shared libraries on aix,
-enter the following in the operating system case-block
-<pre>
- *-aix*) enableshared=no ;;
-</pre>
+ <h1>Porting <acronym>deal.II</acronym> to new systems</h1>
+
+ <p>
+ Since <acronym>deal.II</acronym> uses very few system dependent
+ features, there is a good chance that it might also run on other
+ systems besides the one listed in the
+ <a href="readme.html" targte="body">ReadMe file</a>. Nevertheless,
+ there are often cases where some adjustments are necessary. We will
+ try to give you an impression on what might have to be done in such
+ cases here.
+ </p>
+
+
+ <p>
+ Basically, all the setup of the specifics or a system is done in the
+ ``configure'' script that is run first. This script finds out about
+ operating system, processor, and the like, and then goes on testing
+ whether certain features are present, or if their absence can be
+ worked around.
+ </p>
+
+ <p>
+ ``configure'' is not made for human eyes. It is in fact only a
+ script generated by the ``autoconf'' program from the files
+ ``configure.in'' and ``aclocal.m4'' in the top-level directory of
+ <acronym>deal.II</acronym>. The first contains the order in which
+ macros are called that test for features, interspersed by shell
+ script snippets that do actions depending on the results of the
+ macros. The second file contains the user-defined macros used in
+ ``configure.in'' (most macros are already predefined by autoconf).
+ </p>
+
+ <p>
+ When the ``configure'' script is run on the shell, it writes its
+ results into the file ``common/Make.global_options'' that contains
+ definitions of all compiler flags to be used, as well as paths to
+ programs and other options. In fact, ``configure'' rather takes the
+ file ``common/Make.global_options.in'' and replaces all occurences
+ of variables ``@var@'' by the value of the respective variable in
+ the ``configure'' shell script.
+ </p>
+
+
+
+ <h2>Quick porting</h2>
+
+ <p>
+ If you find something that does not work on your system, then the
+ quickest way to make <acronym>deal.II</acronym> run on your system
+ is to run ``configure'' and change things in
+ ``common/Make.global_options'' so that it works for you. Note that
+ this file is overwritten next time you run ``configure''.
+ </p>
+
+ <p>
+ Most often, problems on new systems are caused by the compiler not
+ accepting certain flags, crashing or producing invalid code on
+ optimization flags, not supporting shared libraries, and the like.
+ All these problems can be solved by changing
+ ``common/Make.global_options'', e.g. by setting the variable
+ ``enable-shared'' to ``no'', or by changing the compiler flags in
+ the variables ``CXXFLAGSG'' (for debug mode) or ``CXXFLAGSO'' (for
+ optimized mode).
+ </p>
+
+
+
+ <h2>Portable porting</h2>
+
+ <p>
+ While the measures shown above make <acronym>deal.II</acronym> run
+ on your system, it does not help other users. Neither does it mean
+ that the next version will run on your system unless you do the same
+ changes over again. There are basically two ways to help us make
+ <acronym>deal.II</acronym> run on your system by default:
+ <ul>
+ <li>
+ <p>
+ You can send us the changes you had to make so that we can include
+ it into the distribution.
+ </p>
+
+ <li>
+ <p>
+ If you know the basics of ``autoconf'', or of shell scripting, you
+ will be able to write tests for the changes that are necessary in
+ ``configure.in'' yourself. There are plenty of examples, both for
+ things that we do depending on the system (for example disabling
+ shared libraries on certain systems) or depending on the compiler
+ (for example using some optimization flags for newer gcc
+ versions), and depending on the results of feature tests. For the
+ latter, you may for example take a look at the macro
+ ``DEAL_II_CHECK_ASSERT_THROW'' in ``aclocal.m4'' that shows how to
+ test whether the ``AssertThrow'' construct in
+ <acronym>deal.II</acronym> works as intended (this check is
+ necessary since some compiler versions get an internal compiler
+ error on DEC Alpha machines for this construct).
+ </p>
+
+ <p>
+ If you have made such changes to ``configure.in'' or
+ ``aclocal.m4'', run ``autoconf'' in the top-level directory to
+ regenerate the ``configure'' script, which you should then run and
+ see whether the output in ``common/Make.global_options'' matches
+ your expectations.
+ </p>
+
+ <p>
+ Of course, we would be happy to hear about the changes you made
+ for your system, so that we can include them into the next version
+ of the library.
+ </p>
+ </ul>
+ </p>
+
+
+ <h2>Cheap porting</h2>
+
+ <p>
+ If for some reason you cannot get <acronym>deal.II</acronym> to run
+ on your system, or if you don't have the expertise to dig into the
+ low-level parts of your system, and if you can provide a test
+ account, you may ask us to try to get things running on your
+ machine. Please note that <em>we can't promise to do that as this is
+ largely a volunteer project and we can only do it if time
+ permits!</em> Nevertheless, we have an interest to have the library
+ running on as many platforms as possible, so the odds are not that
+ bad that we will find some spare time.
+ </p>
+
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