getopt_long_only and slightly unambiguous options

[Felix Janda <felix.janda@posteo.de>]

Hello,

since widl from wine uses the combination, get_opt_long_only seems to
be supposed to be able to differentiate between a short option "-h"
and a long option "--help". Together with the possibility of option
abbreviations, the behavior we are trying to copy is:

-h     -> -h
--help -> --help
-help  -> --help
-he    -> --help
--h    -> --help

However musl maps all of them to --help.

The man page is ambiguous about this aspect and I'm not sure if the
BSDs have the same behavior here. (However I would suspect that the
breakage in widl, when the --help option was added in 2012, would
have been noticed.) As always, it is hard to measure how many
applications (and scripts written against these applications) might
depend on this behavior. Since getopt_long_only is discouraged
maybe these are actually quite few, though.

All in all I think that this a bug in musl which should be fixed.


For the implementation, is it maybe enough in __getopt_long_core to
pass options starting with '-' and of exactly two characters
directly to getopt?

Thanks,
Felix