cygwin_conv_ functions and character encoding

Corinna Vinschen
Mon Feb 8 13:15:00 GMT 2016

On Feb  5 16:47, Thomas Wolff wrote:
> The cygwin path conversion functions ignore the current locale;
> rather they seem to always use the locale environment set when the program
> was started, see test program convloc.c:
> [...]
> In sys_wcstombs in I see:
>   const char *charset = cygheap->locale.charset;
> which is set in internal_setlocale ()...
> In fact, the situation can be fixed by adding after setlocale():
>   cygwin_internal(CW_INT_SETLOCALE);  // -> internal_setlocale();
> (cf.
> but I think those functions should use the proper locale implicitly;
> according to the generic description in
> LC_CTYPE affects ... conversion ... functions, in my opinion this would
> include cygwin-specific conversion functions as well as implicitly called
> conversion (see open() below).
> The same problem applies to the open() function (involving path conversion).
> The wide string function mbstowcs behaves as expected.

Path conversion is a problem when switching locales.  Typically
an application calls setlocale (LC_ALL, "") only and in that case the
conversion works as desired.  We could switch cygwin_path_conv as
you said, but I'm wondering what side-effects that may have.  See
the comment in internal_setlocale().

> The whole issue occurred to me while trying to work around a missing
> conversion functionality, just converting the pathname syntax between
> Unicode strings. The desired options would be like:
>   CCP_POSIX_W_TO_WIN_W,   /* from is wchar_t *posix, to is wchar_t *win32
> */
>   CCP_WIN_W_TO_POSIX_W,   /* from is wchar_t *win32, to is wchar_t *posix
> */

Those are not available because POSIX paths are always multibyte strings.
Patches welcome, though.


Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat
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