alsa-lib-1.0.27.2/snd_pcm_hw_open()
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開始行:
*参照元 [#j2012192]
#backlinks
*説明 [#y67d0d49]
-パス: [[alsa-lib-1.0.27.2/src/pcm/pcm_hw.c]]
-FIXME: これは何？
--説明
**引数 [#d001f79f]
-snd_pcm_t **pcmp
--
--[[alsa-lib-1.0.27.2/snd_pcm_t]]
-const char *name
--
-int card
--
-int device
--
-int subdevice
--
-snd_pcm_stream_t stream
--
--[[alsa-lib-1.0.27.2/snd_pcm_stream_t]]
-int mode
--
-int mmap_emulation ATTRIBUTE_UNUSED
--
--[[alsa-lib-1.0.27.2/ATTRIBUTE_UNUSED]]
-int sync_ptr_ioctl
--
**返り値 [#i0c7a5c3]
-int
--
**参考 [#s862ce10]
*実装 [#q41acca7]
/**
* \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 ...
* \retval zero on success otherwise a negative error code
* \warning Using of this function might be dangerous in...
* of compatibility reasons. The prototype migh...
* 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) + ...
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);
-ファイル名を生成する。
--プレイバック（再生）の場合は、/dev/snd/pcmC0D0p のよう...
---[[alsa-lib-1.0.27.2/SND_PCM_STREAM_PLAYBACK]]
---[[alsa-lib-1.0.27.2/SNDRV_FILE_PCM_STREAM_PLAYBACK]]
--キャプチャ（録音）の場合は、/dev/snd/pcmC0D0c のような...
---[[alsa-lib-1.0.27.2/SND_PCM_STREAM_CAPTURE]]
---[[alsa-lib-1.0.27.2/SNDRV_FILE_PCM_STREAM_CAPTURE]]
--プレイバックでもキャプチャでもないならエラー。
--[[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;
-サブデバイスを選択する。
--[[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;
}
-先ほど生成したファイル名を使って、デバイスファイルを開く。
--[[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;
}
}
-パラメータにより指定されたサブデバイス番号を選択できたか...
--[[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_i...
-
--[[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 [#nd050e34]
終了行:
*参照元 [#j2012192]
#backlinks
*説明 [#y67d0d49]
-パス: [[alsa-lib-1.0.27.2/src/pcm/pcm_hw.c]]
-FIXME: これは何？
--説明
**引数 [#d001f79f]
-snd_pcm_t **pcmp
--
--[[alsa-lib-1.0.27.2/snd_pcm_t]]
-const char *name
--
-int card
--
-int device
--
-int subdevice
--
-snd_pcm_stream_t stream
--
--[[alsa-lib-1.0.27.2/snd_pcm_stream_t]]
-int mode
--
-int mmap_emulation ATTRIBUTE_UNUSED
--
--[[alsa-lib-1.0.27.2/ATTRIBUTE_UNUSED]]
-int sync_ptr_ioctl
--
**返り値 [#i0c7a5c3]
-int
--
**参考 [#s862ce10]
*実装 [#q41acca7]
/**
* \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 ...
* \retval zero on success otherwise a negative error code
* \warning Using of this function might be dangerous in...
* of compatibility reasons. The prototype migh...
* 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) + ...
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);
-ファイル名を生成する。
--プレイバック（再生）の場合は、/dev/snd/pcmC0D0p のよう...
---[[alsa-lib-1.0.27.2/SND_PCM_STREAM_PLAYBACK]]
---[[alsa-lib-1.0.27.2/SNDRV_FILE_PCM_STREAM_PLAYBACK]]
--キャプチャ（録音）の場合は、/dev/snd/pcmC0D0c のような...
---[[alsa-lib-1.0.27.2/SND_PCM_STREAM_CAPTURE]]
---[[alsa-lib-1.0.27.2/SNDRV_FILE_PCM_STREAM_CAPTURE]]
--プレイバックでもキャプチャでもないならエラー。
--[[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;
-サブデバイスを選択する。
--[[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;
}
-先ほど生成したファイル名を使って、デバイスファイルを開く。
--[[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;
}
}
-パラメータにより指定されたサブデバイス番号を選択できたか...
--[[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_i...
-
--[[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 [#nd050e34]
ページ名:
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