double_sockbuf
void double_sockbuf(int, int, int);
double_sockbuf(fd_unix[i], SO_RCVBUF, 0);
double_sockbuf(pair[0], SO_RCVBUF, 1<<20);
double_sockbuf(pair[1], SO_SNDBUF, 1<<20);
double_sockbuf(*fdp, SO_RCVBUF, 0);