[libxml++] RE: [xml] -fexceptions

[Murray Cumming Comneon com]

> From: Graham Bennett [mailto:graham-libxml simulcra org] 
> On Wed, Jul 30, 2003 at 09:29:07AM +0200, 
> Murray Cumming Comneon com wrote:
> > > From: Graham Bennett [mailto:graham-libxml simulcra org] 
> > > It would be 
> > > very useful to
> > > > > be able to throw from SAX callbacks when using libxml 
> from C++.
> > 
> > libxml++ has a solution for this without rebuilding libxml:
> > http://libxmlplusplus.sourceforge.net.
> 
> I have looked at this and there are a few problems with 
> libxml++ from my
> point of view (these might not hold any longer).

I am CCing this to the libxml++ list for you:

>  - exception handling solution requires callbacks to throw only
>    exceptions that derive from the libxml++ exception type.  
> If anything
>    else is thrown then problems will occur if -fexceptions 
> isn't turned
>    on.  I think at least libxml++ should catch (...) and 
> throw a generic
>    exception, for safety's sake.  In my environment it's not practical
>    to catch all possible exceptions and rethrow without losing
>    information about the original exception.
> 
>  - the sax callback interface doesn't expose quite as much information
>    as I can get from using libxml directly.

What do you need exactly?

>  - in the libxml++ design, I am paying for virtual function calls for
>    every callback, which I would rather avoid.

It's just one more function call. I wouldn't worry about it unless you can
prove that it's significant.
 
>  - libxml++ doesn't treat extern "C" properly.  the functions it
>    registers in the libxml sax handler struct should be 
> declared extern
>    "C" but aren't.  This seems to be fine with g++, but other 
> compilers
>    (correctly) report that the type of the function pointer 
> in the struct
>    is different to the type of the function pointer being passed.

A patch would be welcome.
 
>  - finally I couldn't get libxml++ to compile with the sun 
> c++ compiler,
>    although I didn't try too hard.

Details would help us. I'd really like libxml++ to work with Forte.

Murray Cumming
murrayc usa net
www.murrayc.com
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