[:xdigit:] does not work with std::wstring in a Cygwin environment

Hans-Bernhard Bröker HBBroeker@t-online.de
Thu Feb 17 23:11:36 GMT 2022

Am 15.02.2022 um 02:36 schrieb Hans-Bernhard Bröker:
> Am 13.02.2022 um 19:25 schrieb Achim Gratz:

>> There is no OS specific configuration for Cygwin explicitly, instead
>> there is one for newlib that actually gets used.

> This piqued my curiosity, so I had a look at how libstdc++ is built.  I
> found that at least for one crucial source file, called
> ctype_members.cc, cygwin builds do _not_ use the newlib edition, but
> rather the "generic" one.  And that may very well be the problem here.

I've taken the liberty of filing this upstream as a GCC/libstdc++ issue.

The extremely condensed version of the issue is that libstdc++ builds by 
selecting config/os/newlib, but it does not pick --enable-clocale=newlib.

Enabling the more global --with-newlib flag would do the latter for us, 
but it might have other, less desirable effects on top of that.

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