#define FOR_EACH_SNAPSHOT(s, i, sl) \
for ((i) = 0; (i) < (sl)->num_snapshots && ((s) = (sl)->snapshots[(i)]); (i)++)
#define FOR_EACH_SNAPSHOT(s, i, sl) \
for ((i) = 0; (i) < (sl)->num_snapshots && ((s) = (sl)->snapshots[(i)]); (i)++)
#define NUM_COMPARE(x, y) ((int)((x) < (y)) - (int)((x) > (y)))
static int compare_snapshots(const void *a, const void *b)
#define NUM_COMPARE(x, y) ((int)((x) < (y)) - (int)((x) > (y)))
static int compare_snapshots(const void *a, const void *b)