On Wed, 18 May 2022, 17:57 Tom Kacvinsky via Gcc-help, <gcc-help@xxxxxxxxxxx> wrote: > We were happily using -Wall -Wextra -Werror with GCC 8.3.0 and -isystem > for Boost header files to squelch any warnings that would come out of > Boost. > > I recently switched to GCC 12.1 and now we are getting > -Wmaybe-uninitialized errors out of Boost. So I am not sure if > -Wsystem-headers was not part of -Wall -Wextra in GCC 8.3.0 but is now > part of GCC 12.1.0. > No it isn't, it's just that some warnings are now given even if they occur in system headers. > Optimization level plays a role in this. With -O0 (GCC 12.1), the > warning does not happen, but with -O3, it does. > The uninitialised warnings depend on data flow analysis, which only happens with optimization. > So I am not sure of the interaction between optimization, -Wall -Wextra, > -Wsystem-headers, and GCC 8.3.0 and GCC 12.1.0. > > Any ideas? > > Thanks, Tom >
