#include static struct sss{ double f; struct {float m;} snd; } sss; #define _offsetof(st,f) ((char *)&((st *) 16)->f - (char *) 16) int main (void) { printf ("+++Struct float inside struct starting with double:\n"); printf ("size=%d,align=%d\n", sizeof (sss), __alignof__ (sss)); printf ("offset-double=%d,offset-sss-float=%d,\nalign-double=%d,align-sss-float=%d\n", _offsetof (struct sss, f), _offsetof (struct sss, snd), __alignof__ (sss.f), __alignof__ (sss.snd)); return 0; }