Roberto Bagnara bagnara@cs.unipr.it writes:
it would be nice to be able to write `--enable-exceptions' in the GMP configure command line so that, if GMP is compiled with GCC, the `-fexceptions' option is used. This is necessary to have, e.g., `bad_alloc' thrown when virtual memory is exhausted and most serious C++ GMP users will want to do that. Of course, the default can/should be `--disable-exceptions'.
I think that having compile time options that change these kinds of behaviour is asking for trouble. Sooner or later you'll have a system where GMP is installed, and you don't know which way it was compiled, or you have both variants installed in different places and accidentally link with the wrong one. And it probably gets even worse with dynamic linking.
If you want exception raising to be optional, I think you should put the two variants into different namespaces, and then you can have compile time options for building either or both variants.
An alternative is of course to "always" build with exceptions, and say that the GMP C++ ABI includes raising exceptions under certain circumastances. You could leave a compile time option for disabling exceptions (changing the ABI), but then you'd have to shoot any distributor that ships GMP libraries compiled in that incompatible way.
(And at last, you should be able to get what you want with
CXXFLAGS=-fexceptions && ./configure && make
without using any new configure options).
/Niels