SO_RCVLOWAT
#define SO_RCVLOWAT 0x1010
#define SO_RCVLOWAT 0x1004 /* receive low-water mark */
#define SO_RCVLOWAT 0x1004
#define SO_RCVLOWAT 16
#define SO_RCVLOWAT 0x0800
#define SO_RCVLOWAT 18
#define SO_RCVLOWAT 18
#define SO_RCVLOWAT 16
#define SO_RCVLOWAT 18