[geos-devel] Delocalizing the WKT writer?

[Mateusz Loskot]

Sean Gillies wrote:
> Yep, works. Any objections to the changes?
> 
> http://trac.osgeo.org/geos/changeset/2172

Sean,

Generally, it solves the problem of lack of locale independence of GEOS
but this code is far from exception safety.

Frank's CPLLocaleC can solve it but, I am personally allergic to C-style 
locale management.

In C library, there is only one global locale object.
In C++, locale management makes it possible to change locales for 
particular scope/operation only, without influencing any external parts 
of software.
Using setlocale from C library switches C++ library to C-style locale 
management.

I agree with you that implementation WKTReader/Writer is not very clean,
and it mixes use of C and C++ I/O, what also makes a mess regarding 
locale management.

I'm going to try to review and reafactor WKT classes to base on C++ I/O 
then switching locales for particular instance of WKT writing (ie. in 
GEOSGeomToWKT) will be as easy as:


Geometry* g =
...

{
    std::ostringstring os;
    std::locale loc("C"); // global locale untouched
    s.imbue(loc);

    char* wkt = g->toString(os); //

    return wkt;
}

> Would anyone like to see me use a macro instead?

I would not like to see macros :-)

Best regards,
-- 
Mateusz Loskot, http://mateusz.loskot.net
Charter Member of OSGeo, http://osgeo.org