Wrapping BSD select() with JNA

Question

I need to wrap a BSD-like C socket API to Java with JNA. It has basically the same functions as standard BSD socket API.

Wrapping select() is problematic because of the fd_set-structure required in its arguments and the FD_* masking functions (macros) that are needed to handle fd_sets. I tried to crawl through the header files (e.g. sys/select.h in Ubuntu 8.04) but the definitions are not so straightforward. Especially I found it difficult to find the implementation of FD_*-macros, which is needed when wrapping them with JNA's InvocationMapper.

Note: I'm not trying to wrap the standard TCP or unix-socket API, but a custom one. Thus built-in sockets in Java do not fit the bill.

Answer 1

Especially I found it difficult to find the implementation of FD_*-macros, which is needed when wrapping them with JNA's InvocationMapper.

The C pre-processor cpp is useful to find out how macros are expanded. Write a dummy program that uses the relevant macros (it should be lexically correct, but needn't compile), run it through cpp and watch what happens.