On 09/22/2015 11:58 PM, Daniel Richard G. wrote:
> What about having a check in test-c-ctype that compares c_iscntrl() with
> its system counterpart? If the assumption is that alternate EBCDIC
> encodings used with Gnulib will agree with EBCDIC-1047 on these
> characters, then that should be checked.

Good idea.  Done in the attached patch.

> Also, perhaps, that any character for which c_iscntrl() is true should
> return false from most of the other functions...

That's already tested by "ASSERT (! (c_iscntrl (c) && c_isprint (c)));".