ccall documentation

Is there any more complete documentation for ccall than https://svn.cs.ru.nl/repos/clean-tools/trunk/htoclean/CallingCFromClean.html? Also I found this https://clean.cs.ru.nl/Ccall, which is also not very helpful. To be honest until now I used it by looking at and adapting examples. It would be good to put a short documentation somewhere, maybe adapting the Wiki, describing all possible input types.

In particular I'm missing the input types p, A and s from the current documentation. Maybe it's also good to say how to pass *World.

I have a concrete questions about character arrays. From the examples https://svn.cs.ru.nl/repos/clean-tools/trunk/htoclean/Examples/example_array1.icl it seems that for integer and real arrays you have to use A, while for character arrays you have to use s. Why this difference? If I pass a string to a C function expecting a null terminated string, do I have to append "\0" or does s do that automatically?