The test seems to be comparing ctypes and native C bit-field structures, c_int and c_short versus native int and short. In general in C, if a bit-field has type “int” without a signed or unsigned qualifier, it is up to the implementation which mode is chosen. This is different from normal, where int always means signed int.

Since ctypes documents c_int as both meaning “int” and “signed int”, I would say that a ctypes bit-field using c_int should always behave as “signed int”. So perhaps we should just change the test structure to use “signed int” and “signed short”. That should also help avoid the warnings, and may help the Solaris situation (if that is still relevant).

I presume this also affects Python 3.