[Bug libstdc++/63776] [C++11] Regex collate matching not working

["gnu-org at bignm dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63776

--- Comment #2 from Tom Straub <gnu-org at bignm dot com> ---
Hi Tim,

Okay, a program very similar to this using the Boost REGEX library and ICU 4.55
works just fine with this.

According to my understanding, the "char" data type and "std::string" classes
were specifically set up in C++11 to handle UTF-8 sequences.

The "sequence of bytes" are actually valid UNICODE characters. So, there should
be no problem, that is, if the std::regex_constants::collate flag is actually
working, since the application is using <locale> and setting the std::locale to
"pt_BR.UTF-8" (which is supported on my box).

It is acting as if it is still in POSIX or C locale, since it doesn't recognize
the accented characters as "[:alpha:]" class.

Here is my G++ version:

$ g++ --version
g++ (GCC) 4.9.1
Copyright (C) 2014 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Tom