struct S1 { long long inserted_member; int m0; char m1; }; struct S2 { int m0; char m1; }; struct S3 { unsigned to_change; }; int foo(struct S1* s) { return s->m0; } int bar(struct S2* s) { return s->m0; } int baz(struct S3* s) { return s->to_change; }