Setlocale and wchar_t C functions...

[Kralidis,Tom [Burlington]]

FYI msGetLanguage can probably leverage MAP/LOCALE as well.

..Tom

 

> -----Original Message-----
> From: UMN MapServer Developers List 
> [mailto:MAPSERVER-DEV at LISTS.UMN.EDU] On Behalf Of Steve Lime
> Sent: 22 June, 2007 12:39 PM
> To: MAPSERVER-DEV at LISTS.UMN.EDU
> Subject: Re: [UMN_MAPSERVER-DEV] Setlocale and wchar_t C functions...
> 
> Great, thanks for the clarification.
> 
> Steve
> 
> >>> On 6/22/2007 at 10:55 AM, in message
> <75b4b93e0706220855k7b2d7797gb608527da8a11d0d at mail.gmail.com>,
>  "Umberto Nicoletti" <umberto.nicoletti at gmail.com> wrote:
> > On 6/22/07, Steve Lime <Steve.Lime at dnr.state.mn.us> wrote:
> >> Hi all: I'm working to resolve bug 1921 with deals with 
> curved labels 
> >> and
> > multibyte character sets. The current label path
> >> code doesn't handle multibyte character sets. Fortunately 
> standard C 
> >> (on
> > Linux and MacOS anyway) have some functions
> >> to deal with the problem. For example mbstowcs converts from a 
> >> multibyte
> > string to a wide character string. The behavior
> >> of those functions depend on the locale. Unless you are in a local 
> >> with
> > multibyte characters those functions don't work
> >> with multibyte chars and assume single byte chars. Found that out 
> >> trying to
> > draw Chinese characters with the default US-EN
> >> locale. If I set the local to one with multibyte characters then I 
> >> could
> > debug.
> >>
> >> A couple of questions then:
> >>
> >>   - what would folks think about adding a LOCALE parameter to the 
> >> main
> > mapObj? We could to a setlocale(LC_ALL, msyytext)
> >> immediately. If not set, then whatever the system has set 
> takes over.
> >>
> >>   - as I understand it setlocale has a global effect so 
> perhaps there 
> >> might
> > be some down stream side effects, although I can't
> >> think what they might be. I suppose for long running 
> processes there 
> >> could
> > be issues. I can see where a company might want
> >> to provide maps in different languages from the same server.
> > 
> > Steve,
> > calling setlocale from mapserver will also change the locale of the 
> > mapscript language which means, for Java, a global change of the 
> > locale behaviour in the application server which is, I 
> believe, not a 
> > really good idea. The same happens with python, c#, etc and PHP 
> > mapscript loaded as shared module will change the locale of apache.
> > I also seem to remember that calls to setlocale are not thread safe.
> > 
> > A similar question was raised some time ago and at that time it was 
> > somehow decided not to call setlocale from within mapserver.
> > See the thread titled: 'Proposing to call setlocale( 
> LC_ALL, "C" ) in 
> > msSetup()'
> > 
> > To set the locale for a process one should use the usual 
> environment 
> > variables (LANG or LC_ALL). In particular it is possible to 
> do this on 
> > a per-map basis for the CGI version of mapserver either 
> from whithin 
> > apache or with a wrapper shell script.
> > 
> > Regards,
> > Umberto
> > 
> > 
> >>
> >>   - are the wide character functions (stdlib.h) available 
> on all platforms?
> >>
> >> Steve
> >>
>