projects / linux-block.git / blame
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1 | .. Permission is granted to copy, distribute and/or modify this |
| 2 | .. document under the terms of the GNU Free Documentation License, | |
| 3 | .. Version 1.1 or any later version published by the Free Software | |
| 4 | .. Foundation, with no Invariant Sections, no Front-Cover Texts | |
| 5 | .. and no Back-Cover Texts. A copy of the license is included at | |
| 6 | .. Documentation/media/uapi/fdl-appendix.rst. | |
| 7 | .. | |
| 8 | .. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections | |
| 9 | ||
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10 | .. _dmx_fwrite: |
| 11 | ||
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12 | ======================== |
| 13 | Digital TV demux write() | |
| 14 | ======================== | |
| 47d23e36 | 15 | |
| 15e7d615 | 16 | Name |
| 586027ce | 17 | ---- |
| 47d23e36 | 18 | |
| 699f19e3 | 19 | Digital TV demux write() |
| 47d23e36 | 20 | |
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21 | |
| 22 | Synopsis | |
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23 | -------- |
| 24 | ||
| 1b81f010 | 25 | .. c:function:: ssize_t write(int fd, const void *buf, size_t count) |
| cf8076c3 | 26 | :name: dvb-dmx-write |
| 47d23e36 | 27 | |
| 15e7d615 | 28 | Arguments |
| 586027ce | 29 | --------- |
| 47d23e36 | 30 | |
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31 | ``fd`` |
| 32 | File descriptor returned by a previous call to :c:func:`open() <dvb-ca-open>`. | |
| 47d23e36 | 33 | |
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34 | ``buf`` |
| 35 | Buffer with data to be written | |
| 47d23e36 | 36 | |
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37 | ``count`` |
| 38 | Number of bytes at the buffer | |
| 47d23e36 | 39 | |
| 15e7d615 | 40 | Description |
| 586027ce | 41 | ----------- |
| 47d23e36 | 42 | |
| 586027ce | 43 | This system call is only provided by the logical device |
| 883dfe8a | 44 | ``/dev/dvb/adapter?/dvr?``, associated with the physical demux device that |
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45 | provides the actual DVR functionality. It is used for replay of a |
| 46 | digitally recorded Transport Stream. Matching filters have to be defined | |
| 883dfe8a | 47 | in the corresponding physical demux device, ``/dev/dvb/adapter?/demux?``. |
| 586027ce | 48 | The amount of data to be transferred is implied by count. |
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49 | |
| 50 | ||
| 15e7d615 | 51 | Return Value |
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52 | ------------ |
| 53 | ||
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54 | On success 0 is returned. |
| 55 | ||
| 56 | On error -1 is returned, and the ``errno`` variable is set | |
| 57 | appropriately. | |
| 58 | ||
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59 | .. tabularcolumns:: |p{2.5cm}|p{15.0cm}| |
| 60 | ||
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61 | .. flat-table:: |
| 62 | :header-rows: 0 | |
| 63 | :stub-columns: 0 | |
| 9a721b9b | 64 | :widths: 1 16 |
| 47d23e36 | 65 | |
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66 | - - ``EWOULDBLOCK`` |
| 67 | - No data was written. This might happen if ``O_NONBLOCK`` was | |
| 47d23e36 | 68 | specified and there is no more buffer space available (if |
| 9a721b9b | 69 | ``O_NONBLOCK`` is not specified the function will block until buffer |
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70 | space is available). |
| 71 | ||
| 9a721b9b | 72 | - - ``EBUSY`` |
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73 | - This error code indicates that there are conflicting requests. The |
| 74 | corresponding demux device is setup to receive data from the | |
| 75 | front- end. Make sure that these filters are stopped and that the | |
| 9a721b9b | 76 | filters with input set to ``DMX_IN_DVR`` are started. |
| 47d23e36 | 77 | |
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78 | The generic error codes are described at the |
| 79 | :ref:`Generic Error Codes <gen-errors>` chapter. |