https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96293
Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |INVALID --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- The packed attribute means that _Alignof (S) is 1. If you want the structure to be aligned to its largest member you have to use __attribute__((packed,aligned(__alignof__(unsigned int))))