19 #define	SETUP(fd, rfds, tv) do {				\  argument
21 	FD_SET((fd), &(rfds));					\
59 child(int fd, int num)  in child()  argument
67 		fd = open(FIFONAME, O_RDONLY | O_NONBLOCK);  in child()
68 		if (fd < 0)  in child()
71 	if (fd >= FD_SETSIZE)  in child()
72 		errx(1, "fd = %d too large for select()", fd);  in child()
75 		SETUP(fd, rfds, tv);  in child()
76 		if (select(fd + 1, &rfds, NULL, NULL, &tv) < 0)  in child()
90 		report(num++, "0", 1, FD_ISSET(fd, &rfds));  in child()
106 	SETUP(fd, rfds, tv);  in child()
107 	if (select(fd + 1, &rfds, NULL, NULL, &tv) < 0)  in child()
109 	report(num++, "1", 0, FD_ISSET(fd, &rfds));  in child()
115 	SETUP(fd, rfds, tv);  in child()
116 	if (select(fd + 1, &rfds, NULL, NULL, &tv) < 0)  in child()
118 	report(num++, "2", 1, FD_ISSET(fd, &rfds));  in child()
119 	if (read(fd, buf, sizeof buf) != 1)  in child()
121 	SETUP(fd, rfds, tv);  in child()
122 	if (select(fd + 1, &rfds, NULL, NULL, &tv) < 0)  in child()
124 	report(num++, "2a", 0, FD_ISSET(fd, &rfds));  in child()
130 	SETUP(fd, rfds, tv);  in child()
131 	if (select(fd + 1, &rfds, NULL, NULL, &tv) < 0)  in child()
133 	report(num++, "3", 1, FD_ISSET(fd, &rfds));  in child()
139 	 * start quite from scratch since the read fd is not new.  Check  in child()
146 	SETUP(fd, rfds, tv);  in child()
147 	if (select(fd + 1, &rfds, NULL, NULL, &tv) < 0)  in child()
149 	report(num++, "4", 0, FD_ISSET(fd, &rfds));  in child()
155 	SETUP(fd, rfds, tv);  in child()
156 	if (select(fd + 1, &rfds, NULL, NULL, &tv) < 0)  in child()
158 	report(num++, "5", 1, FD_ISSET(fd, &rfds));  in child()
169 	SETUP(fd, rfds, tv);  in child()
170 	if (select(fd + 1, &rfds, NULL, NULL, &tv) < 0)  in child()
172 	report(num++, "6", 1, FD_ISSET(fd, &rfds));  in child()
173 	if (read(fd, buf, sizeof buf) != 1)  in child()
175 	SETUP(fd, rfds, tv);  in child()
176 	if (select(fd + 1, &rfds, NULL, NULL, &tv) < 0)  in child()
178 	report(num++, "6a", 1, FD_ISSET(fd, &rfds));  in child()
193 		fd1 = fd;  in child()
194 		fd = fd2;  in child()
195 		SETUP(fd, rfds, tv);  in child()
196 		if (select(fd + 1, &rfds, NULL, NULL, &tv) < 0)  in child()
198 		report(num++, "6b", 1, FD_ISSET(fd, &rfds));  in child()
199 		fd = fd1;  in child()
200 		SETUP(fd, rfds, tv);  in child()
201 		if (select(fd + 1, &rfds, NULL, NULL, &tv) < 0)  in child()
203 		report(num++, "6c", 1, FD_ISSET(fd, &rfds));  in child()
205 		SETUP(fd, rfds, tv);  in child()
206 		if (select(fd + 1, &rfds, NULL, NULL, &tv) < 0)  in child()
208 		report(num++, "6d", 1, FD_ISSET(fd, &rfds));  in child()
210 	close(fd);  in child()
217 parent(int fd)  in parent()  argument
223 		fd = open(FIFONAME, O_WRONLY | O_NONBLOCK);  in parent()
224 		if (fd < 0)  in parent()
232 	if (write(fd, "", 1) != 1)  in parent()
239 	if (close(fd) != 0)  in parent()
248 	fd = open(FIFONAME, O_WRONLY | O_NONBLOCK);  in parent()
249 	if (fd < 0)  in parent()
256 	if (write(fd, "", 1) != 1)  in parent()
263 	if (close(fd) != 0)  in parent()
275 	int fd[2], num;  in main()  local
287 			fd[0] = -1;  in main()
288 			fd[1] = -1;  in main()
292 			    fd) != 0)  in main()
296 			if (pipe(fd) != 0)  in main()
305 			(void)close(fd[1]);  in main()
306 			child(fd[0], num);  in main()
309 			(void)close(fd[0]);  in main()
310 			parent(fd[1]);  in main()