See http://www.siao2.com/2004/12/03/274288.aspx
And http://www.siao2.com/2013/04/04/10407543.aspx For some background and related bugs in several products. I hope this blog will stay alive. (The author passed away recently) Bert From: Bert Huijben [mailto:b...@qqmail.nl] Sent: donderdag 26 november 2015 00:22 To: dev@httpd.apache.org Subject: RE: apr_token_* conclusions (was: Better casecmpstr[n]?) The example was the other way around. Changing SS to ß is not a valid transform, but the other way is. There are also transforms on the combined AE characters, etc. That Turkish ‘I’ problem is the only case I know of where the collation actually changes behavior within the usual western alphabet of ASCII characters. Bert From: Mikhail T. [mailto:mi+t...@aldan.algebra.com] Sent: woensdag 25 november 2015 23:19 To: dev@httpd.apache.org <mailto:dev@httpd.apache.org> Subject: Re: apr_token_* conclusions (was: Better casecmpstr[n]?) On 25.11.2015 14:10, Mikhail T. wrote: Two variables, LC_CTYPE and LC_COLLATE control this text processing behavior. The above is the correct lower case transliteration for Turkish. In German, the upper case correspondence of sharp-S ß is 'SS', but multi-char translation is not provided by the simple tolower/toupper functions. So, the concern is, some hypothetical header, such as X-ASSIGN-TO may, after going through the locale-aware strtolower() unexpectedly become x-aßign-to? I just tested the above on both FreeBSD and Linux, and the results are encouraging: % echo STRASSE | env LANG=de_DE.ISO8859 tr '[[:upper:]]' '[[:lower:]]' strasse Thus, I contend, using C-library will not cause invalid results, and the only reason to have Apache's own implementation is performance, but not correctness. -mi
