pfds              823 user/usertests.c   int pfds[2];
pfds              843 user/usertests.c   pipe(pfds);
pfds              850 user/usertests.c     close(pfds[0]);
pfds              851 user/usertests.c     if(write(pfds[1], "x", 1) != 1)
pfds              853 user/usertests.c     close(pfds[1]);
pfds              858 user/usertests.c   close(pfds[1]);
pfds              859 user/usertests.c   if(read(pfds[0], buf, sizeof(buf)) != 1){
pfds              863 user/usertests.c   close(pfds[0]);