#include #include /* try compiling this with -m32 vs -m64 * * with mac os x and gcc, * on -m32 the int64_t gets aligned at +4 * on -m64 the int64_t gets aligned at +8 */ static const struct s_t { int i; int64_t j; } s; int main() { if ((long)&s.j % 8 != 0) printf("non-aligned int64\n"); else printf("aligned int64\n"); }