Dolphin, the GameCube and Wii emulator - Forums

https://github.com/dolphin-emu/hwtests/blob/master/gxtest/Test.cpp this one has the actual networking code

https://github.com/dolphin-emu/hwtests/blob/master/gxtest/bitfield.cpp this one is a sample application using that code

As said before, GC networking is broken in libogc and will likely crash. Wii networking uses completely different code and should work fine (except some of the configuration IPs are iffy/hardcoded in Dolphin).