On Tue, Oct 6, 2015 at 4:51 PM, Aaron Ballman <aa...@aaronballman.com> wrote: > On Tue, Oct 6, 2015 at 4:49 PM, Joerg Sonnenberger via cfe-commits > <cfe-commits@lists.llvm.org> wrote: >> On Tue, Oct 06, 2015 at 04:20:05PM -0400, Aaron Ballman via cfe-commits >> wrote: >>> On Tue, Oct 6, 2015 at 4:12 PM, Joerg Sonnenberger via cfe-commits >>> <cfe-commits@lists.llvm.org> wrote: >>> > On Mon, Oct 05, 2015 at 07:36:08PM +0000, Aaron Ballman via cfe-commits >>> > wrote: >>> >> C-style variadic functions (using an ellipsis) can be dangerous in C++ >>> >> due to the inherit lack of type safety with argument passing. Better >>> >> alternatives exist, such as function currying (like STL stream objects >>> >> use), or function parameter packs. This patch adds a checker to >>> >> diagnose definitions of variadic functions in C++ code, but still >>> >> allows variadic function declarations, as those can be safely used to >>> >> good effect for SFINAE patterns. >>> > >>> > I would restrict this a bit to exclude function definitions with C >>> > linkage. If you have such a ABI requirement, you normally can't replace >>> > it with any of the alternatives. >>> >>> Under what circumstances would you run into this issue with C++ code? >>> The only circumstance I can think of is if you have a C API that takes >>> a function pointer to a varargs function as an argument. Is that the >>> situation you are thinking of, or are there others? >> >> Consider a stdio implementation written in C++? Wouldn't the >> implementation of e.g. vprintf trigger exactly this warning? > > It would, but it would also trigger a *lot* of warnings that aren't > directed at implementers as well, such as anything about relying on > implementation-defined or undefined behavior (like the implementation > of offsetof(), as a trivial example). It's a good point to keep in > mind though.
Thank you for the suggestion, Joerg -- I've implemented it in r249555, and updated the CERT rule wording to match. ~Aaron _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
