On 02/05/2019 05:07 PM, Jeff Law wrote: > FWIW, I've been doing Fedora rawhide builds with gcc-9 since early Jan. > Not everything builds with -Wall -Werror, but lots of packages do. > I've only seen one maybe-uninit warning cause problems -- it was > spurious and for a memory object. I didn't dig into it at all.
Do you have insight into how many Fedora packages explicitly disable maybe-uninit? I really don't know the answer to that, but I'd at least keep that in mind as a possible reason for the warning seemingly not causing trouble often. GDB disables it (or rather, removes it from -Werror), and I wouldn't be surprised if other C++ programs do the same, when they start using std::optional more. Since boost::optional also triggers the same warnings, set may be even larger than C++11-or-later programs. I don't know how to search the Fedora codebase, but a github search for "-Wno-maybe-uninitialized" shows > 100k hits: https://github.com/search?q=-Wno-maybe-uninitialized&type=Code and a search for -Wno-error=maybe-uninitialized shows >10k: https://github.com/search?q=-Wno-error%3Dmaybe-uninitialized&type=Code That's a much higher hit rate than say -Wno-array-bounds or -Wno-format-overflow, or -Wno-stringop-overflow, which were some searches I tried. > > In contrast things like the missing NUL termination warnings, buffer > overflow warnings, NULL strings to *printf* warnings, etc all caught > numerous (dozens) of real bugs. I mention it because it's one of the > ways I know packages are building with -Wall -Werror :-) Thanks, Pedro Alves
