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