[vtkusers] [Insight-developers] wx/vtk weirdness

Mon Nov 30 15:42:48 EST 2009

Not only locale for language like French are different for thousand
separator but also English is different from C|POSIX !!

 An integer of value 2000 will generate the string "2000" in POSIX|C
locale but will generate the string "2,000" in "en_US.UTF-8" locale.

Example of test that was failing with "en_US.UTF-8":

http://www.cdash.org/CDash/testDetails.php?test=37688960&build=483148

This test is now fixed by forcing C|POSIX in the C++ stream.

On Mon, Nov 30, 2009 at 1:04 PM, Bill Lorensen <bill.lorensen at gmail.com> wrote:
> Tom,
>
> I don't think we need to be concerned with the per-thread issue. My
> changes are all local to the methods that need c-locale's. For
> example, surrounding the ReadImageInformation calls with save/restore
> locales in many readers fixes the readers.
>
> Maybe you can try my simple itkLocale class. I'll send it in a separate mail.
>
> Bill
>
> On Mon, Nov 30, 2009 at 12:57 PM, Bill Lorensen <bill.lorensen at gmail.com> wrote:
>> Tom,
>>
>> What I have done is create an itk class, itkLocale, that in its
>> constructor saves the current c-locale and creates a new one. The
>> destructor restores the original locale.
>>
>> C++-locales are handled explicitly with imbue.
>>
>> I'll try your approach in the itkLocale class.
>>
>> BTW, I have not checked in any code yet.
>>
>> I think it is time to start an ITK Policy and Procedure page for
>> internationalization on the itk wiki.
>>
>> It can include the work you are doing with unicode.
>>
>> I'll give it a stab today. Then we can start a new thread on itk developers.
>>
>> Bill
>>
>>
>> On Mon, Nov 30, 2009 at 12:50 PM, Tom Vercauteren
>> <tom.vercauteren at gmail.com> wrote:
>>> Hi Bill,
>>>
>>> I would just like to mention that in our group we have been facing
>>> several issues with locale support on mac.
>>>
>>> Looking at the documentation of xlocale:
>>>  http://developer.apple.com/Mac/library/documentation/Darwin/Reference/ManPages/man3/xlocale.3.html
>>> you will see that setlocale will have absolutely no effect (on mac,
>>> maybe on windows also
>>> http://msdn.microsoft.com/en-us/library/26c0tb7x.aspx ) if a
>>> per-thread locale had been specified.
>>>
>>> Using newlocale, duplocale, uselocale and freelocale seems a better option:
>>>  http://www.opengroup.org/onlinepubs/9699919799/functions/uselocale.html
>>>  http://www.opengroup.org/onlinepubs/9699919799/functions/newlocale.html
>>>  http://www.opengroup.org/onlinepubs/9699919799/functions/duplocale.html
>>>  http://www.opengroup.org/onlinepubs/9699919799/functions/freelocale.html
>>>
>>>
>>> For example, to put only the LC_NUMERIC parameter to C, here is how we
>>> chose to proceed:
>>>
>>> // Create a new locale based on a copy of the current one (which need
>>> not be explicitly set)
>>> // but where LC_NUMERIC has been modified to match the C locale
>>> locale_t tempLocale = newlocale(LC_NUMERIC_MASK, NULL, NULL);
>>> // Use this new locale and store the current one to reset it aftwards
>>> locale_t previousLocale = uselocale(templocale);
>>>
>>> [Actual useful code]
>>>
>>> // Reset the locale to the previous one
>>> uselocale(previousLocale)
>>> // More house keeing
>>> freelocale(tempLocale)
>>>
>>>
>>> Actually, on mac we also had to do explicitly create thread-specific
>>> locale to avoid some random crash in heavily threaded code. But that
>>> is a slightly different topic
>>>
>>> Cheers,
>>> Tom
>>>
>>>
>>> On Mon, Nov 30, 2009 at 17:08, Bill Lorensen <bill.lorensen at gmail.com> wrote:
>>>> I've already made a pass through the itk readers. Several were broken
>>>> wrt locale.
>>>>
>>>> I used a combination of C++ and C locale api's. I encapsulated the C
>>>> locale in and itk::Locale class.
>>>>
>>>> I have not checked in any changes yet, but I went from over 40 failing
>>>> I/O tests down to 0.
>>>>
>>>> Bill
>>>>
>>>> On Mon, Nov 30, 2009 at 10:58 AM, Marcus D. Hanwell
>>>> <marcus.hanwell at kitware.com> wrote:
>>>>> On Saturday 28 November 2009 13:19:58 Bill Lorensen wrote:
>>>>>> Luis,
>>>>>>
>>>>>> Actually, we can surround certain functions with c-style setlocale and
>>>>>> it solves the problems. I already fixed StimulateImageIO,
>>>>>> PolygonGroupSpatialObjectXMLFile and VTKImageIO. I have not checked in
>>>>>> any changes yet. Still more investigation is needed as to the best
>>>>>> portable solution.
>>>>>>
>>>>>> I do this:
>>>>>>   const char *originalLocale;
>>>>>>   char *currentLocale;
>>>>>>   originalLocale = setlocale(LC_NUMERIC, NULL);
>>>>>>   currentLocale = strdup(originalLocale ? originalLocale : "C");
>>>>>>   setlocale(LC_NUMERIC, "C");
>>>>>>
>>>>>> ......
>>>>>>
>>>>>>
>>>>>> setlocale(LC_NUMERIC, currentLocale);
>>>>>>         free(currentLocale);
>>>>>
>>>>> A page from the Apache C++ resource site gives some good explanations of why
>>>>> the C++ locale should be preferred. Mainly because the C locale is a global
>>>>> resource, whereas in the C++ locale instances of the locale can be created.
>>>>>
>>>>> http://stdcxx.apache.org/doc/stdlibug/24-3.html
>>>>>>
>>>>>> For example in StimulateImageIO I surrounded the calls in
>>>>>> StimulateImageIO::InternalReadImageInformation with the above
>>>>>> snippets.
>>>>>>
>>>>>> There are other readers/writers that use C++ streams, and there we
>>>>>> will have to imbue.
>>>>>
>>>>> I think that using the C locale is probably the easiest short term solution,
>>>>> but to support GUIs using different locales we should be using the C++ locale
>>>>> class and associated API. Otherwise users of our libraries may suffer from
>>>>> subtle bugs if reading and writing files in separate threads that are all
>>>>> using C locales.
>>>>>>
>>>>>> Even in some code that uses streams, people still use sscanf, atof,
>>>>>> etc. In the long run we probably should address these cases with
>>>>>> stream replacements.
>>>>>
>>>>> We should aim to ensure new code uses C++ streams and imbue, and replace
>>>>> existing code with C++ streams. As you say this should probably be part of a
>>>>> larger i18n effort which would involve using Unicode strings and other changes
>>>>> to our libraries.
>>>>>
>>>>> Marcus
>>>>>
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>>
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