alsa-lib-1.0.27.2/snd_pcm_hw_open() の履歴(No.1)

• 履歴一覧
• 差分 を表示
• 現在との差分 を表示
• ソース を表示
• alsa-lib-1.0.27.2/snd_pcm_hw_open() へ行く。
  • 1 (2013-09-30 (月) 02:25:54)

---

参照元†

• alsa-lib-1.0.27.2/_snd_pcm_hw_open()

説明†

• パス: alsa-lib-1.0.27.2/src/pcm/pcm_hw.c

• FIXME: これは何？
  • 説明

引数†

返り値†

参考†

実装†

/**
 * \brief Creates a new hw PCM
 * \param pcmp Returns created PCM handle
 * \param name Name of PCM
 * \param card Number of card
 * \param device Number of device
 * \param subdevice Number of subdevice
 * \param stream PCM Stream
 * \param mode PCM Mode
 * \param mmap_emulation Obsoleted parameter
 * \param sync_ptr_ioctl Use SYNC_PTR ioctl rather than mmap for control structures
 * \retval zero on success otherwise a negative error code
 * \warning Using of this function might be dangerous in the sense
 *          of compatibility reasons. The prototype might be freely
 *          changed in future.
 */
int snd_pcm_hw_open(snd_pcm_t **pcmp, const char *name,
		    int card, int device, int subdevice,
		    snd_pcm_stream_t stream, int mode,
		    int mmap_emulation ATTRIBUTE_UNUSED,
		    int sync_ptr_ioctl)
{
	char filename[sizeof(SNDRV_FILE_PCM_STREAM_PLAYBACK) + 20];
	const char *filefmt;
	int ret = 0, fd = -1;
	int attempt = 0;
	snd_pcm_info_t info;
	int fmode;
	snd_ctl_t *ctl;

• • alsa-lib-1.0.27.2/SNDRV_FILE_PCM_STREAM_PLAYBACK

• alsa-lib-1.0.27.2/snd_pcm_info_t

• • alsa-lib-1.0.27.2/snd_ctl_t

	assert(pcmp);

	if ((ret = snd_ctl_hw_open(&ctl, NULL, card, 0)) < 0)
		return ret;

• • alsa-lib-1.0.27.2/snd_ctl_hw_open()

	switch (stream) {
	case SND_PCM_STREAM_PLAYBACK:
		filefmt = SNDRV_FILE_PCM_STREAM_PLAYBACK;
		break;
	case SND_PCM_STREAM_CAPTURE:
		filefmt = SNDRV_FILE_PCM_STREAM_CAPTURE;
		break;
	default:
		SNDERR("invalid stream %d", stream);
		return -EINVAL;
	}
	sprintf(filename, filefmt, card, device);

• • alsa-lib-1.0.27.2/SND_PCM_STREAM_PLAYBACK

• alsa-lib-1.0.27.2/SNDRV_FILE_PCM_STREAM_PLAYBACK

• • alsa-lib-1.0.27.2/SND_PCM_STREAM_CAPTURE

• alsa-lib-1.0.27.2/SNDRV_FILE_PCM_STREAM_CAPTURE

• • alsa-lib-1.0.27.2/SNDERR()

      __again:
      	if (attempt++ > 3) {
		ret = -EBUSY;
		goto _err;
	}
	ret = snd_ctl_pcm_prefer_subdevice(ctl, subdevice);
	if (ret < 0)
		goto _err;

• • alsa-lib-1.0.27.2/snd_ctl_pcm_prefer_subdevice()

	fmode = O_RDWR;
	if (mode & SND_PCM_NONBLOCK)
		fmode |= O_NONBLOCK;
	if (mode & SND_PCM_ASYNC)
		fmode |= O_ASYNC;
	if (mode & SND_PCM_APPEND)
		fmode |= O_APPEND;

• • alsa-lib-1.0.27.2/SND_PCM_NONBLOCK

• alsa-lib-1.0.27.2/SND_PCM_ASYNC

• • alsa-lib-1.0.27.2/SND_PCM_APPEND

	fd = snd_open_device(filename, fmode);
	if (fd < 0) {
		ret = -errno;
		SYSMSG("open '%s' failed (%i)", filename, ret);
		goto _err;
	}

• • alsa-lib-1.0.27.2/snd_open_device()

• alsa-lib-1.0.27.2/SYSMSG()

	if (subdevice >= 0) {
		memset(&info, 0, sizeof(info));
		if (ioctl(fd, SNDRV_PCM_IOCTL_INFO, &info) < 0) {
			ret = -errno;
			SYSMSG("SNDRV_PCM_IOCTL_INFO failed (%i)", ret);
			goto _err;
		}
		if (info.subdevice != (unsigned int) subdevice) {
			close(fd);
			goto __again;
		}
	}

• • alsa-lib-1.0.27.2/SNDRV_PCM_IOCTL_INFO

	snd_ctl_close(ctl);
	return snd_pcm_hw_open_fd(pcmp, name, fd, 0, sync_ptr_ioctl);

• • alsa-lib-1.0.27.2/snd_ctl_close()

• alsa-lib-1.0.27.2/snd_pcm_hw_open_fd()

       _err:
	snd_ctl_close(ctl);
	return ret;
}

コメント†