Re: [TUHS] communication files: interprocess IO before pipes

On SCO UNIX 3.2V4 pipes where simulated as follows int fd[2] struct strfdinsert ins; /* * First open the stream clone device "/dev/spx" twice, * obtaining the two file descriptors. */ if ( (fd[0] = open(SPX_DEVICE, O_RDWR)) < 0) { gen_trace(gtr_flag, "-gen_pipe(): -open(fd[0]): %s\n", strerror(errno)); break; } if ( (fd[1] = open(SPX_DEVICE, O_RDWR)) < 0) { gen_trace(gtr_flag, ">gen_pipe(): -open(fd[1]): %s\n", strerror(errno)); close(fd[0]); break; } /* * Now link these two streams together with an * I_FDINSERT ioctl. */ ins.ctlbuf.buf = (char *) &pointer; /* no ctl info, just the ptr */ ins.ctlbuf.maxlen = sizeof(queue_t *); ins.ctlbuf.len = sizeof(queue_t *); ins.databuf.buf = (char *) 0; /* no data to send */ ins.databuf.len = -1; /* magic: must be -1, not 0, for stream pipe */ ins.databuf.maxlen = 0; ins.fildes = fd[1]; /* the fd to connect with fd[0] */ ins.flags = 0; /* nonpriority message */ ins.offset = 0; /* offset of pointer in control buffer */ if (ioctl(fd[0], I_FDINSERT, (char * ) &ins) < 0) { gen_trace(gtr_flag, ">gen_pipe(): -ioctl(I_FDINSERT): %s\n", strerror(errno)); close(fd[0]); close(fd[1]); break; } /* * reset close_on_exec flag */ gen_trace(gtr_flag, ">gen_pipe(): +fcntl()\n"); if ((rc = fcntl(fd[0], F_SETFD, 0)) == -1) gen_trace(gtr_flag, ">gen_pipe(): -fcntl(fd0, close_on_exec): %s\n", strerror(errno)); if ((rc = fcntl(fd[1], F_SETFD, 0)) == -1) gen_trace(gtr_flag, ">gen_pipe(): -fcntl(fd1, close_on_exec): %s\n", strerror(errno)); rc = 0; break;