#include <u.h>#define NOPLAN9DEFINES#include <libc.h>#include <sys/socket.h> /* * We use socketpair to get a two-way pipe. * The pipe still doesn't preserve message boundaries. * Worse, it cannot be reopened via /dev/fd/NNN on Linux. */intp9pipe(int fd[2]){	return socketpair(AF_UNIX, SOCK_STREAM, 0, fd);}