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Re: Bug in collation functions?

On 10/29/2015 4:30 AM, Corinna Vinschen wrote:
On Oct 29 08:50, Corinna Vinschen wrote:
On Oct 28 21:58, Eric Blake wrote:
On 10/28/2015 04:14 PM, Ken Brown wrote:
It's my understanding that collation is supposed to take whitespace and
punctuation into account in the POSIX locale but not in other locales.

Not quite right. It is up to the locale definition whether whitespace
affects collation.  But you are correct that in the POSIX locale,
whitespace must not be ignored in collation.

This doesn't seem to be the case on Cygwin.  Here's a test case using
wcscoll, but the same problem occurs with strcoll.

That's because the locale definitions are different in cygwin than they
are in glibc.  But it is not a bug in Cygwin; POSIX allows for different
systems to have different locale definitions while still using the same
locale name like en_US.UTF-8.

Btw, strcoll and wcscoll in Cygwin are implemented using the Windows
function CompareStringW with the LCID set to the locale matching the
POSIX locale setting.  I'm rather glad I didn't have to implement this
by myself... :}

OTOH, CompareString has a couple of flags to control its behaviour, see

Right now Cygwin calls CompareStringW with dwCmpFlags set to 0, but there
discussion how to change the settings to more closely resemble the rules
on Linux.

E.g.  wcscoll simply calls wcscmp rather than CompareStringW for the
C/POSIX locale anyway.  So, would it makes sense to set the flags to
NORM_IGNORESYMBOLS in other locales?

I think so. That's what the native Windows build of emacs does in this situation. (I came across the issue because one of the tests in the emacs test suite was failing on Cygwin.)


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