SECSPERDAY
#define SECSPERDAY (24 * SECSPERHOUR)
#define SECSPERDAY (24L * 60L * 60L)
#define SECSPERDAY (24L * 60L * 60L)
#define SECSPERDAY ((int_fast32_t)SECSPERHOUR * HOURSPERDAY)
#define SECSPERDAY ((long)SECSPERHOUR * HOURSPERDAY)