https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111669
--- Comment #4 from Xi Ruoyao <xry111 at gcc dot gnu.org> --- (In reply to Zeb Figura from comment #3) > (In reply to Xi Ruoyao from comment #2) > > (In reply to Xi Ruoyao from comment #1) > > > The warning given for the reduced test case is correct because it does not > > > make sense. It should be just rewritten as > > > > I mean, the code does not make sense. > > > > And the warning is given exactly because GCC is optimizing the strcpy call > > to unreachable. > > If GetWindowsDirectoryA() was idempotent, and GetSystemDirectory16() had no > other users, that might be true, but as it is I don't think so. > > The pattern both of those functions call is, much like snprintf(), you pass > a buffer and a size, and if the size is 0 then they'll return the size that > would have been written if there was a large enough buffer. In that case the > buffer can be NULL. In trying to reduce the test case down to the minimal > possible complexity I obscured that fact, but regardless I don't think the > reduced testcase is nonsensical. Then that's why -Wnonnull is a warning, not an error. Using -Werror is just telling the compiler "you can reject valid code", anyway.
