taglinefilesource code
BUF_SIZE651net/unix/sock.cif (cando >(part = BUF_SIZE - upd->bp_tail)) 
BUF_SIZE654net/unix/sock.cupd->bp_tail =(upd->bp_tail + cando) &(BUF_SIZE-1);
BUF_SIZE740net/unix/sock.cif (cando >(part = BUF_SIZE - pupd->bp_head))
BUF_SIZE744net/unix/sock.cpupd->bp_head =(pupd->bp_head + cando) &(BUF_SIZE-1);
BUF_SIZE63net/unix/unix.h(BUF_SIZE-1))
BUF_SIZE64net/unix/unix.h#define UN_BUF_SPACE(UPD)  ((BUF_SIZE-1) - UN_BUF_AVAIL(UPD))