while(running) {
FD_ZERO(&rd);
if(readin)
FD_SET(STDIN_FILENO, &rd);
FD_SET(xfd, &rd);
i = select(xfd + 1, &rd, NULL, NULL, NULL);
while(running) {
FD_ZERO(&rd);
if(readin)
FD_SET(STDIN_FILENO, &rd);
FD_SET(xfd, &rd);
i = select(xfd + 1, &rd, NULL, NULL, NULL);