From ea638efe9bfb930b2176596a68b02d67b5a56e82 Mon Sep 17 00:00:00 2001
From: wolf Attention: before starting a port to a new system, check
-the readme file for your system. Configurations must be done in the file configure.in of
-the root directory of deal.II. At the end, look for
-a section of the structure
-Porting deal.II to new systems
-
-Compiler flags
-
-A configuration by setting the CXXFLAGS variable will soon be
-supported.
-
-Configuration file
-
-
-case "$target" in
- *-linux*) ...;;
- *-aix*) ...;;
-esac
-
-case "$target" in
- alpha*-linux*) ...;;
-esac
-
-The first case block allows you to adjust parameters for a certain
-operating system, the second for an operating system/machine
-configuration.
Some of the features of the library are turned on and off by ---enable-xxx and --with-xxx=yyy 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 -
- *-aix*) enableshared=no ;; -+
+ Since deal.II 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 + ReadMe file. 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. +
+ + ++ 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. +
+ ++ ``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 + deal.II. 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). +
+ ++ 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. +
+ + + ++ If you find something that does not work on your system, then the + quickest way to make deal.II 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''. +
+ ++ 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). +
+ + + ++ While the measures shown above make deal.II 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 + deal.II run on your system by default: +
+ You can send us the changes you had to make so that we can include + it into the distribution. +
+ ++ 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 + deal.II works as intended (this check is + necessary since some compiler versions get an internal compiler + error on DEC Alpha machines for this construct). +
+ ++ 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. +
+ ++ 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. +
++ If for some reason you cannot get deal.II 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 we can't promise to do that as this is + largely a volunteer project and we can only do it if time + permits! 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. +
+