C++ (Cpp) a4l_sys_open Examples

Example #1

File: descriptor.c Project: ChunHungLiu/xenomai

/**
 * @brief Open an Analogy device and basically fill the descriptor
 *
 * @param[out] dsc Device descriptor
 * @param[in] fname Device name
 *
 * @return 0 on success. Otherwise:
 *
 * - -EINVAL is returned if some argument is missing or wrong; the
 *    fname and the dsc pointer should be checked; check also the
 *    kernel log ("dmesg")
 * - -EFAULT is returned if a user <-> kernel transfer went wrong
 *
 */
int a4l_open(a4l_desc_t *dsc, const char *fname)
{
	int ret;

	/* Basic checking */
	if (dsc == NULL)
		return -EINVAL;

	/* Initializes the descriptor */
	memset(dsc, 0, sizeof(a4l_desc_t));

	/* Opens the driver */
	dsc->fd = a4l_sys_open(fname);
	if (dsc->fd < 0)
		return dsc->fd;

	/* Basically fills the descriptor */
	ret = a4l_sys_desc(dsc->fd, dsc, A4L_BSC_DESC);
	if (ret < 0) {
		a4l_sys_close(dsc->fd);
	}

	return ret;
}

Example #2

File: analogy_config.c Project: JackieXie168/xenomai

int main(int argc, char *argv[])
{
	int c;
	char *devfile;
	int err = 0, fd = -1;

	/* Compute arguments */
	while ((c =
		getopt_long(argc, argv, "hvqVrR:W:S:", a4l_conf_opts,
			    NULL)) >= 0) {
		switch (c) {
		case 'h':
			do_print_usage();
			goto out_a4l_config;
		case 'v':
			vlevel = 2;
			break;
		case 'q':
			vlevel = 0;
			break;
		case 'V':
			do_print_version();
			goto out_a4l_config;
		case 'r':
			actions |= DO_DETACH;
			break;
		case 'R':
		case 'W':
			fprintf(stdout,
				"analogy_config: the option --read-buffer-size "
				"and --write-buffer-size will be deprecated; "
				"please use --buffer-size instead (-S)\n");
		case 'S':
			actions |= DO_BUFCONFIG;
			bufsize = strtoul(optarg, NULL, 0);
			break;
		default:
			do_print_usage();
			goto out_a4l_config;
		}
	}

	/* Here we have choice:
	   - if the option -r is set, only one additional option is
	     useful
	   - if the option -S is set without no attach options
	   - if the option -S is set with attach options */

	if ((actions & DO_DETACH) && argc - optind < 1 ) {
		fprintf(stderr, "analogy_config: specify a device to detach\n");
		goto out_a4l_config;
	}

	if ((actions & DO_DETACH) && (actions & DO_BUFCONFIG)) {
		fprintf(stderr,
			"analogy_config: skipping buffer size configuration"
			"because of detach action\n");
	}

	if (!(actions & DO_DETACH) &&
	    !(actions & DO_BUFCONFIG) && argc - optind < 2) {
		do_print_usage();
		goto out_a4l_config;
	} else if (!(actions & DO_DETACH) && argc - optind >= 2)
		actions |= DO_ATTACH;

	/* Whatever the action, we need to retrieve the device path */
	devfile = argv[optind];
	/* Init the descriptor structure */

	/* Open the specified file */
	fd = a4l_sys_open(devfile);
	if (fd < 0) {
		err = fd;
		fprintf(stderr,
			"analogy_config: a4l_open failed err=%d\n", err);
		goto out_a4l_config;
	}

	if (actions & DO_DETACH) {

		err = a4l_sys_detach(fd);
		if (err < 0)
			fprintf(stderr,
				"analogy_config: detach failed err=%d\n", err);
		goto out_a4l_config;
	}

	if (actions & DO_ATTACH) {

		a4l_lnkdesc_t lnkdsc;

		memset(&lnkdsc, 0, sizeof(a4l_lnkdesc_t));

		/* Fill the descriptor with the driver name */
		lnkdsc.bname = argv[optind + 1];
		lnkdsc.bname_size = strlen(argv[optind + 1]);

		/* Process driver-specific options */
 		if (argc - optind == 3) {

			err = process_extra_arg(&lnkdsc, argv[optind + 2]);
			if (err < 0)
				goto out_a4l_config;
		}

		/* Go... */
		err = a4l_sys_attach(fd, &lnkdsc);
		if (err < 0) {
			fprintf(stderr,
				"analogy_config: attach failed err=%d\n", err);
			goto out_a4l_config;
		}

		if (lnkdsc.opts != NULL)
			free(lnkdsc.opts);
	}

	if (actions & DO_BUFCONFIG) {

		err = a4l_sys_bufcfg(fd, A4L_BUF_DEFMAGIC, bufsize);
		if (err < 0) {
			fprintf(stderr,
				"analogy_config: bufffer configuraiton failed "
				"(err=%d)\n", err);
			goto out_a4l_config;
		}
	}

out_a4l_config:

	if (fd >= 0)
		a4l_sys_close(fd);

	return err;
}