USEC_PER_SEC
#define USEC_PER_SEC 1000000L
#define USEC_PER_SEC 1000000L
#define USEC_PER_SEC 1000000L
#define USEC_PER_SEC 1000000UL
#define USEC_PER_SEC 1000000UL
#define USEC_PER_SEC 1000000UL
#define USEC_PER_SEC 1000000L
#define USEC_PER_SEC 1000000L
#define USEC_PER_SEC (USEC_PER_MSEC * MSEC_PER_SEC)