Re: const version of Gdk::Pixbuf::save()

[Murray Cumming <murrayc murrayc com>]

On Thu, 2012-06-21 at 19:45 +0200, Kjell Ahlstedt wrote:
> Gdk::Pixbuf::save() and save_to_buffer() are C++ wrappers around the C 
> functions gdk_pixbuf_savev() and gdk_pixbuf_save_to_buffer(), resp. 
> Those C functions take a "GdkPixbuf* pixbuf" parameter (i.e. not const 
> GdkPixbuf* pixbuf). I don't know why. It's unintuitive that they should 
> modify the GdkPixbuf, but perhaps they do. Anyway, that's the reason why 
> there are no const versions of the corresponding C++ member functions.
> 
> A solution (not very attractive, I admit) is to take a copy of the 
> Pixbuf with Gdk::Pixbuf::copy() and save the copy.
> 
> If you don't get a better answer here, you can try asking on a gtk+ list 
> (e.g. gtk-app-devel-list) why the gdk_pixbuf_save*() functions don't 
> take const GdkPixbuf*.

The C APIs generally don't use const for complex data types. C doesn't
have everything that's needed to make const as useful, or not annoying,
as in C++. It doesn't mean much. If this should really be const in C++
then we can add that and deprecate the non-const method.



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