1372 Chapter 63
/* ... Initialize 'timeout', 'readfds', and 'nfds' for select() */if (pipe(pfd) == -1)
errExit("pipe");FD_SET(pfd[0], &readfds); /* Add read end of pipe to 'readfds' */
nfds = max(nfds, pfd[0] + 1); /* And adjust 'nfds' if required */flags = fcntl(pfd[0], F_GETFL);
if (flags == -1)
errExit("fcntl-F_GETFL");
flags |= O_NONBLOCK; /* Make read end nonblocking */
if (fcntl(pfd[0], F_SETFL, flags) == -1)
errExit("fcntl-F_SETFL");flags = fcntl(pfd[1], F_GETFL);
if (flags == -1)
errExit("fcntl-F_GETFL");
flags |= O_NONBLOCK; /* Make write end nonblocking */
if (fcntl(pfd[1], F_SETFL, flags) == -1)
errExit("fcntl-F_SETFL");sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART; /* Restart interrupted read()s */
sa.sa_handler = handler;
if (sigaction(SIGINT, &sa, NULL) == -1)
errExit("sigaction");while ((ready = select(nfds, &readfds, NULL, NULL, pto)) == -1 &&
errno == EINTR)
continue; /* Restart if interrupted by signal */
if (ready == -1) /* Unexpected error */
errExit("select");if (FD_ISSET(pfd[0], &readfds)) { /* Handler was called */
printf("A signal was caught\n");for (;;) { /* Consume bytes from pipe */
if (read(pfd[0], &ch, 1) == -1) {
if (errno == EAGAIN)
break; /* No more bytes */
else
errExit("read"); /* Some other error */
}/* Perform any actions that should be taken in response to signal */
}
}/* Examine file descriptor sets returned by select() to see
which other file descriptors are ready */}
–––––––––––––––––––––––––––––––––––––––––––––––––––––from altio/self_pipe.c