bug in mbrtowc?

Pedro Izecksohn pedro.izecksohn@gmail.com
Tue Jul 28 10:39:00 GMT 2009


  The bug is in O.P.'s code as &s is not being passed to mbrtowc.

  I'm on Ubuntu. I do not have Cygwin here.

  I should consume some calories before trying to debug anything.

On Tue, Jul 28, 2009 at 6:14 AM, Corinna
Vinschen<corinna-cygwin@cygwin.com> wrote:
> On Jul 27 22:56, Andy Koppe wrote:
>> I've encountered what looks like a bug in mbrtowc's handling of UTF-8.
>> Here's an example:
>>
>> #include <stdio.h>
>> #include <locale.h>
>> #include <stdlib.h>
>> #include <wchar.h>
>>
>> int main(void) {
>>   wchar_t wc;
>>   size_t ret;
>>   mbstate_t s = { 0 };
>>   puts(setlocale(LC_CTYPE, "en_GB.UTF-8"));
>>   printf("%i\n", mbrtowc(&wc, "\xe2", 1, 0));
>>   printf("%i\n", mbrtowc(&wc, "\x94", 1, 0));
>>   printf("%i\n", mbrtowc(&wc, "\x84", 1, 0));
>>   printf("%x\n", wc);
>>   return 0;
>> }
>>
>> The sequence E2 94 84 should translate to U+2514. Instead, the second
>> and third calls to mbrtowc report encoding errors. It does work
>> correctly if the three bytes are passed to mbrtowc() in one go:
>>
>>   printf("%i\n", mbrtowc(&wc, "\xe2\x94\x84", 3, 0));
>
> That's a bug in the newlib function __utf8_mbtowc.  I'm really surprised
> that this bug has never been reported before since it's in the code for
> years, probably since it has been introduced in 2002.
>
> I'll follow up on the newlib list.
>
>
> Thanks for the report and especially thanks for the testcase,
> Corinna

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