Thank you, Jonathan, for your quick reply. Jonathan Wakely <jwakely.gcc@xxxxxxxxx> writes: > On 28 August 2012 16:32, Christoph Groth wrote: >> I've been unable to find a description of this issue in any changelog. >> Actually, I wonder whether the behavior of 4.6 or that of 4.7 is the >> correct one with regard to the C++ language standard. >> >> Is this a known issue which has been fixed in 4.7, or rather a >> regression from 4.6? > > The change in behaviour might be due to the patch for > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48883 > > But I think the program has undefined behaviour according to > [expr.reinterpret.cast]/6, because it calls a function through a > pointer to a different function type. Specifically, something<long> > which has type void*(Class<long>*) is called through a pointer of type > void*(*)(void*). Unfortunately, this is the official way of programming Python extensions in C/C++. [1] The void* of my example stands for PyObject*. I'm not sure whether the behavior is indeed undefined when something<long> will be called through a pointer of type void*(*)(void*) IF the void* argument always points to a Class<long> object. So, I guess, I either have to keep all the explicit instantiations in my program (many) or make all these template functions static methods of a class which can then be instantiated explicitly with a single statement. [1] http://docs.python.org/py3k/extending/newtypes.html
