[orbitcpp-list] question about ORBit-tools

[Ronald G. <rga...@pi...>]

hey guys,
     got a question about some code I found in orbitcpp_tools.hh.

There is some code which goes like so:

#ifdef ORBITCPP_HAVE_BAD_CAST
	#define ORBITCPP_NARROW_OR_NULL(type,item) \
		type *result; \
		try { \
			result = dynamic_cast<type *>(item); \
		} \
		catch (bad_cast) {\
		    result = NULL; \
		}
#else
	#warning ORBit-C++ will not detect narrowing errors on pseudo objects.
	#define ORBITCPP_NARROW_OR_NULL(type,item) \
		type *result = static_cast<type *>(item);
#endif


a few questions/comments:

     1)  In C++, dynamic casting to a pointer type doesn't throw
exceptions, it just returns a 1.  bad_cast is thrown on dynamic casts
to references...ie, I don't think that code will work.

     2)  I looked at the code to set ORBITCPP_HAVE_BAD_CAST in
acinclude.m4... as far as I recall, in g++, bad_cast can be found in
<typeinfo> instead of <exception>.  I think this is the wrong place
according to c++ standards, but if we're going to use it, we might as
well support the most common compiler for this stuff.

     3)  I think that the above could be implemented as a template,
n'est-ce pas?  That would be the c++ way

just wondering what's thought about that...

ron