added --fifo in help page

main.cpp

@@ -1155,7 +1155,7 @@ int client_event_loop()
 
 		ret = epoll_ctl(epollfd, EPOLL_CTL_ADD, fifo_fd, &ev);
 		if (ret!= 0) {
-			mylog(log_fatal,"add fifo_fd to epoll error %s\n",strerror);
+			mylog(log_fatal,"add fifo_fd to epoll error %s\n",strerror(errno));
 			myexit(-1);
 		}
 		mylog(log_info,"fifo_file=%s\n",fifo_file);
@@ -1393,7 +1393,7 @@ int server_event_loop()
 
 		ret = epoll_ctl(epollfd, EPOLL_CTL_ADD, fifo_fd, &ev);
 		if (ret!= 0) {
-			mylog(log_fatal,"add fifo_fd to epoll error %s\n",strerror);
+			mylog(log_fatal,"add fifo_fd to epoll error %s\n",strerror(errno));
 			myexit(-1);
 		}
 		mylog(log_info,"fifo_file=%s\n",fifo_file);

misc.cpp

@@ -121,6 +121,8 @@ void print_help()
 	printf("other options:\n");
 	printf("    --conf-file           <string>        read options from a configuration file instead of command line.\n");
 	printf("                                          check example.conf in repo for format\n");
+	printf("    --fifo                <string>        use a fifo(named pipe) for sending commands to the running program,\n");
+	printf("                                          check readme.md in repository for supported commands.\n");
 	printf("    --log-level           <number>        0:never    1:fatal   2:error   3:warn \n");
 	printf("                                          4:info (default)     5:debug   6:trace\n");
 //	printf("\n");