| /* Test of select() substitute, reading or writing from a given file descriptor. |
| Copyright (C) 2008-2020 Free Software Foundation, Inc. |
| |
| This program is free software: you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <https://www.gnu.org/licenses/>. */ |
| |
| /* Written by Bruno Haible <bruno@clisp.org>, 2008. */ |
| |
| #include <config.h> |
| |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <sys/select.h> |
| |
| int |
| main (int argc, char *argv[]) |
| { |
| if (argc == 4) |
| { |
| char mode = argv[1][0]; |
| |
| if (mode == 'r' || mode == 'w') |
| { |
| int fd = atoi (argv[2]); |
| |
| if (fd >= 0) |
| { |
| const char *result_file_name = argv[3]; |
| FILE *result_file = fopen (result_file_name, "wb"); |
| |
| if (result_file != NULL) |
| { |
| fd_set fds; |
| struct timeval timeout; |
| int ret; |
| |
| FD_ZERO (&fds); |
| FD_SET (fd, &fds); |
| timeout.tv_sec = 0; |
| timeout.tv_usec = 10000; |
| ret = (mode == 'r' |
| ? select (fd + 1, &fds, NULL, NULL, &timeout) |
| : select (fd + 1, NULL, &fds, NULL, &timeout)); |
| if (ret < 0) |
| { |
| perror ("select failed"); |
| exit (1); |
| } |
| if ((ret == 0) != ! FD_ISSET (fd, &fds)) |
| { |
| fprintf (stderr, "incorrect return value\n"); |
| exit (1); |
| } |
| fprintf (result_file, "%d\n", ret); |
| exit (0); |
| } |
| } |
| } |
| } |
| fprintf (stderr, "Usage: test-select-fd mode fd result-file-name\n"); |
| exit (1); |
| } |