Step 2: Add documentation for function calls. Signed-off-by: Stefan Herdler <herdler@xxxxxxxxxxxxxx> --- Possibly unused: AUDIO_SET_ID AUDIO_SET_STREAMTYPE AUDIO_BILINGUAL_CHANNEL_SELECT > + > +AUDIO_SET_ID > +------------ > + > +AUDIO_SET_STREAMTYPE > +-------------------- This ioctls are dealing with stream types and IDs defined in ITU-T H.222.0. The intention is pretty clear when reading the introduction of Annex Q there. However this ioctls doesn't seem to be used anywhere. >> + >> +AUDIO_BILINGUAL_CHANNEL_SELECT >> +------------------------------ >> + > [...] > > IMO, this is also another problematic API. Its name seems to be related > to language selection. However, multi-language usually uses different > PIDs. Maybe in the past they used to place two languages at the same > PID, one at the left channel and the other at the right one? It seems to be intended this way. This kind multi-language was popular in the beginning of DVB, but it has been mostly replaced by multiple PIDs. The AV7110 uses AUDIO_CHANNEL_SELECT for the same purpose. This 2 ioctls look redundant to me and AUDIO_BILINGUAL_CHANNEL_SELECT doesn't seem to be used at all. .../media/dvb/legacy_dvb_audio.rst | 1195 +++++++++++++++++ 1 file changed, 1195 insertions(+) diff --git a/Documentation/userspace-api/media/dvb/legacy_dvb_audio.rst b/Documentation/userspace-api/media/dvb/legacy_dvb_audio.rst index 4c994f8c97e5..45d330c33caf 100644 --- a/Documentation/userspace-api/media/dvb/legacy_dvb_audio.rst +++ b/Documentation/userspace-api/media/dvb/legacy_dvb_audio.rst @@ -445,3 +445,1198 @@ Description A call to `AUDIO_GET_CAPABILITIES`_ returns an unsigned integer with the following bits set according to the hardwares capabilities. + + +----- + + +Audio Function Calls +==================== + + +AUDIO_STOP +---------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_STOP + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_STOP) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - File descriptor returned by a previous call to `open()`_. + + - .. + + - ``int request`` + + - :cspan:`1` Equals ``AUDIO_STOP`` for this command. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl call asks the Audio Device to stop playing the current +stream. + +Return Value +~~~~~~~~~~~~ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + + +----- + + +AUDIO_PLAY +---------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_PLAY + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_PLAY) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - File descriptor returned by a previous call to `open()`_. + + - .. + + - ``int request`` + + - :cspan:`1` Equals ``AUDIO_PLAY`` for this command. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl call asks the Audio Device to start playing an audio stream +from the selected source. + +Return Value +~~~~~~~~~~~~ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + + +----- + + +AUDIO_PAUSE +----------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_PAUSE + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_PAUSE) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - Equals ``AUDIO_PAUSE`` for this command. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl call suspends the audio stream being played. Decoding and +playing are paused. It is then possible to restart again decoding and +playing process of the audio stream using `AUDIO_CONTINUE`_ command. + +Return Value +~~~~~~~~~~~~ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + + +----- + + +AUDIO_CONTINUE +-------------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_CONTINUE + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_CONTINUE) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - Equals ``AUDIO_CONTINUE`` for this command. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl restarts the decoding and playing process previously paused +with `AUDIO_PAUSE`_ command. + +Return Value +~~~~~~~~~~~~ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + + +----- + + +AUDIO_SELECT_SOURCE +------------------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_SELECT_SOURCE + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_SELECT_SOURCE, + audio_stream_source_t source) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - Equals ``AUDIO_SELECT_SOURCE`` for this command. + + - .. + + - `audio_stream_source_t`_ ``source`` + + - Indicates the source that shall be used for the Audio stream. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl call informs the audio device which source shall be used for +the input data. The possible sources are demux or memory. If +``AUDIO_SOURCE_MEMORY`` is selected, the data is fed to the Audio Device +through the write command. If ``AUDIO_SOURCE_DEMUX`` is selected, the data +is directly transferred from the onboard demux-device to the decoder. +Note: This only supports DVB-devices with one demux and one decoder so far. + +Return Value +~~~~~~~~~~~~ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + + +----- + + +AUDIO_SET_MUTE +-------------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_SET_MUTE + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_SET_MUTE, int state) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - :cspan:`1` Equals ``AUDIO_SET_MUTE`` for this command. + + - .. + + - :rspan:`2` ``int state`` + + - :cspan:`1` Indicates if audio device shall mute or not. + + - .. + + - TRUE ( != 0 ) + + - mute audio + + - .. + + - FALSE ( == 0 ) + + - unmute audio + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl is for DVB devices only. To control a V4L2 decoder use the +V4L2 :ref:`VIDIOC_DECODER_CMD` with the +``V4L2_DEC_CMD_START_MUTE_AUDIO`` flag instead. + +This ioctl call asks the audio device to mute the stream that is +currently being played. + +Return Value +~~~~~~~~~~~~ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + + +----- + + +AUDIO_SET_AV_SYNC +----------------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_SET_AV_SYNC + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_SET_AV_SYNC, int state) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - :cspan:`1` Equals ``AUDIO_AV_SYNC`` for this command. + + - .. + + - :rspan:`2` ``int state`` + + - :cspan:`1` Tells the DVB subsystem if A/V synchronization + shall be ON or OFF. + + - .. + + - TRUE ( != 0 ) + + - AV-sync ON. + + - .. + + - FALSE ( == 0 ) + + - AV-sync OFF. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl call asks the Audio Device to turn ON or OFF A/V +synchronization. + +Return Value +~~~~~~~~~~~~ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + + +----- + + +AUDIO_SET_BYPASS_MODE +--------------------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_SET_BYPASS_MODE + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_SET_BYPASS_MODE, int mode) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - :cspan:`1` Equals ``AUDIO_SET_BYPASS_MODE`` for this command. + + - .. + + - :rspan:`2` ``int mode`` + + - :cspan:`1` Enables or disables the decoding of the current + Audio stream in the DVB subsystem. + - .. + + - TRUE ( != 0 ) + + - Disable bypass + + - .. + + - FALSE ( == 0 ) + + - Enable bypass + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl call asks the Audio Device to bypass the Audio decoder and +forward the stream without decoding. This mode shall be used if streams +that can’t be handled by the DVB system shall be decoded. Dolby +DigitalTM streams are automatically forwarded by the DVB subsystem if +the hardware can handle it. + +Return Value +~~~~~~~~~~~~ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + + +----- + + +AUDIO_CHANNEL_SELECT +-------------------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_CHANNEL_SELECT + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_CHANNEL_SELECT, + audio_channel_select_t) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - Equals ``AUDIO_CHANNEL_SELECT`` for this command. + + - .. + + - `audio_channel_select_t`_ ``ch`` + + - Select the output format of the audio (mono left/right, stereo). + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl is for DVB devices only. To control a V4L2 decoder use the +V4L2 ``V4L2_CID_MPEG_AUDIO_DEC_PLAYBACK`` control instead. + +This ioctl call asks the Audio Device to select the requested channel if +possible. + +Return Value +~~~~~~~~~~~~ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + + +----- + + +AUDIO_GET_STATUS +---------------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_GET_STATUS + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_GET_STATUS, + struct audio_status *status) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - Equals AUDIO_GET_STATUS for this command. + + - .. + + - ``struct`` `audio_status`_ ``*status`` + + - Returns the current state of Audio Device. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl call asks the Audio Device to return the current state of the +Audio Device. + +Return Value +~~~~~~~~~~~~ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + + +----- + + +AUDIO_GET_CAPABILITIES +---------------------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_GET_CAPABILITIES + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_GET_CAPABILITIES, + unsigned int *cap) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - Equals ``AUDIO_GET_CAPABILITIES`` for this command. + + - .. + + - ``unsigned int *cap`` + + - Returns a bit array of supported sound formats. + Bits are defined in `audio encodings`_. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl call asks the Audio Device to tell us about the decoding +capabilities of the audio hardware. + +Return Value +~~~~~~~~~~~~ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + + +----- + + +AUDIO_CLEAR_BUFFER +------------------ + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_CLEAR_BUFFER + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_CLEAR_BUFFER) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - Equals ``AUDIO_CLEAR_BUFFER`` for this command. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl call asks the Audio Device to clear all software and hardware +buffers of the audio decoder device. + +Return Value +~~~~~~~~~~~~ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + + +----- + + +AUDIO_SET_ID +------------ + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_SET_ID + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_SET_ID, int id) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - Equals ``AUDIO_SET_ID`` for this command. + + - .. + + - ``int id`` + + - Audio sub-stream id. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl selects which sub-stream is to be decoded if a program or +system stream is sent to the video device. + +If no audio stream type is set the id has to be in range [0xC0,0xDF] +for MPEG sound, in [0x80,0x87] for AC3 and in [0xA0,0xA7] for LPCM. +See ITU-T H.222.0 | ISO/IEC 13818-1 for further description. + +If the stream type is set with `AUDIO_SET_STREAMTYPE`_, specifies the +id just the sub-stream id of the audio stream and only the first 5 bits +(& 0x1F) are recognized. + +Return Value +~~~~~~~~~~~~ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + + +----- + + +AUDIO_SET_MIXER +--------------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_SET_MIXER + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_SET_MIXER, audio_mixer_t *mix) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - Equals ``AUDIO_SET_MIXER`` for this command. + + - .. + + - ``audio_mixer_t *mix`` + + - Mixer settings. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl lets you adjust the mixer settings of the audio decoder. + +Return Value +~~~~~~~~~~~~ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + + +----- + + +AUDIO_SET_STREAMTYPE +-------------------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_SET_STREAMTYPE + +.. code-block:: c + + int ioctl(fd, int request = AUDIO_SET_STREAMTYPE, int type) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - Equals ``AUDIO_SET_STREAMTYPE`` for this command. + + - .. + + - ``int type`` + + - Stream type. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl tells the driver which kind of audio stream to expect. This +is useful if the stream offers several audio sub-streams like LPCM and +AC3. + +Stream types defined in ITU-T H.222.0 | ISO/IEC 13818-1 are used. + + +Return Value +~~~~~~~~~~~~ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``EINVAL`` + + - Type is not a valid or supported stream type. + + +----- + + +AUDIO_BILINGUAL_CHANNEL_SELECT +------------------------------ + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_BILINGUAL_CHANNEL_SELECT + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_BILINGUAL_CHANNEL_SELECT, + audio_channel_select_t) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - Equals ``AUDIO_BILINGUAL_CHANNEL_SELECT`` for this command. + + - .. + + - ``audio_channel_select_t ch`` + + - Select the output format of the audio (mono left/right, stereo). + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl has been replaced by the V4L2 +``V4L2_CID_MPEG_AUDIO_DEC_MULTILINGUAL_PLAYBACK`` control +for MPEG decoders controlled through V4L2. + +This ioctl call asks the Audio Device to select the requested channel +for bilingual streams if possible. + +Return Value +~~~~~~~~~~~~ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + + +----- + + +open() +------ + +Synopsis +~~~~~~~~ + +.. code-block:: c + + #include <fcntl.h> + +.. c:function:: int open(const char *deviceName, int flags) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``const char *deviceName`` + + - Name of specific audio device. + + - .. + + - :rspan:`3` ``int flags`` + + - :cspan:`1` A bit-wise OR of the following flags: + + - .. + + - ``O_RDONLY`` + + - read-only access + + - .. + + - ``O_RDWR`` + + - read/write access + + - .. + + - ``O_NONBLOCK`` + - | Open in non-blocking mode + | (blocking mode is the default) + +Description +~~~~~~~~~~~ + +This system call opens a named audio device (e.g. +``/dev/dvb/adapter0/audio0``) for subsequent use. When an open() call has +succeeded, the device will be ready for use. The significance of +blocking or non-blocking mode is described in the documentation for +functions where there is a difference. It does not affect the semantics +of the open() call itself. A device opened in blocking mode can later be +put into non-blocking mode (and vice versa) using the F_SETFL command +of the fcntl system call. This is a standard system call, documented in +the Linux manual page for fcntl. Only one user can open the Audio Device +in O_RDWR mode. All other attempts to open the device in this mode will +fail, and an error code will be returned. If the Audio Device is opened +in O_RDONLY mode, the only ioctl call that can be used is +`AUDIO_GET_STATUS`_. All other call will return with an error code. + +Return Value +~~~~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``ENODEV`` + + - Device driver not loaded/available. + + - .. + + - ``EBUSY`` + + - Device or resource busy. + + - .. + + - ``EINVAL`` + + - Invalid argument. + + +----- + + +close() +------- + +Synopsis +~~~~~~~~ + +.. c:function:: int close(int fd) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + +Description +~~~~~~~~~~~ + +This system call closes a previously opened audio device. + +Return Value +~~~~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``EBADF`` + + - Fd is not a valid open file descriptor. + +----- + + +write() +------- + +Synopsis +~~~~~~~~ + +.. code-block:: c + + size_t write(int fd, const void *buf, size_t count) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``void *buf`` + + - Pointer to the buffer containing the PES data. + + - .. + + - ``size_t count`` + + - Size of buf. + +Description +~~~~~~~~~~~ + +This system call can only be used if ``AUDIO_SOURCE_MEMORY`` is selected +in the ioctl call `AUDIO_SELECT_SOURCE`_. The data provided shall be in +PES format. If ``O_NONBLOCK`` is not specified the function will block +until buffer space is available. The amount of data to be transferred is +implied by count. + +Return Value +~~~~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``EPERM`` + + - :cspan:`1` Mode ``AUDIO_SOURCE_MEMORY`` not selected. + + - .. + + - ``ENOMEM`` + + - Attempted to write more data than the internal buffer can hold. + + - .. + + - ``EBADF`` + + - Fd is not a valid open file descriptor. -- 2.34.0
