https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69763
Bug ID: 69763 Summary: _Alignof(double) in C gives different results from alignof(double) in C++ Product: gcc Version: 6.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: richard-gccbugzilla at metafoo dot co.uk Target Milestone: --- See also bug 52023. On i386, according to GCC we have _Alignof(double) == 4, but according to G++ we have alignof(double) == 8. This makes no sense, as the same words are used to specify the semantics in both languages, and this creates a gratuitous incompatibility between GCC's C and C++ modes.