[ESPResSo-devel] Switching to C++ compiler

[Olaf Lenz]

Hello ESPResSo developers!

On our ICP group retreat, we have decided that we want to switch
ESPResSo to C++ as soon as possible. Meanwhile, C++ is widely spread and
reasonable standardized so that we dare to do this step.

For now, this only means that we will change the default compiler to be
a C++ compiler and adapt the code such that it compiles.

For the future, this allows all developers to use the improvements of
C++ over C. However, we do not plan to excessively use all C++ features,
but rather a limited subset of C++ (that might change over time). On the
following page, we will write down how we believe that the ESPResSo
C-code developers can benefit from C++, and also what features of C++ we
do not want to use:

  http://espressomd.org/wiki/C%2B%2B

In the github repo I have created a branch "cpp" that contains the
efforts of this change so far. I have already managed to compile the
code with the ESPResSo++ compiler, however so far the build system uses
a C-compiler by default. To test it, you have to use configure
CC="mpic++" (or the like).

In my tests, at least when using GCC, the compilation has become
significantly slower (roughly by a factor of 4). The performance of the
executable should not change, however, just to be sure I have also
tested this, and the speed is indeed the same as with the pure C compiler.

If anybody of you sees any problems with this switch, now is the right
time to say so.

Olaf
-- 
Dr. rer. nat. Olaf Lenz
Institut für Computerphysik, Allmandring 3, D-70569 Stuttgart
Phone: +49-711-685-63607

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