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/userspace-api/media/fdl-appendix.rst. 7.. 8.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections 9 10.. _dmx_fread: 11 12======================= 13Digital TV demux read() 14======================= 15 16Name 17---- 18 19Digital TV demux read() 20 21 22Synopsis 23-------- 24 25.. c:function:: size_t read(int fd, void *buf, size_t count) 26 :name: dvb-dmx-read 27 28Arguments 29--------- 30 31``fd`` 32 File descriptor returned by a previous call to :c:func:`open() <dvb-ca-open>`. 33 34 ``buf`` 35 Buffer to be filled 36 37``count`` 38 Max number of bytes to read 39 40Description 41----------- 42 43This system call returns filtered data, which might be section or Packetized 44Elementary Stream (PES) data. The filtered data is transferred from 45the driver’s internal circular buffer to ``buf``. The maximum amount of data 46to be transferred is implied by count. 47 48.. note:: 49 50 if a section filter created with 51 :c:type:`DMX_CHECK_CRC <dmx_sct_filter_params>` flag set, 52 data that fails on CRC check will be silently ignored. 53 54 55Return Value 56------------ 57 58On success 0 is returned. 59 60On error -1 is returned, and the ``errno`` variable is set 61appropriately. 62 63.. tabularcolumns:: |p{2.5cm}|p{15.0cm}| 64 65.. flat-table:: 66 :header-rows: 0 67 :stub-columns: 0 68 :widths: 1 16 69 70 - - ``EWOULDBLOCK`` 71 - No data to return and ``O_NONBLOCK`` was specified. 72 73 - - ``EOVERFLOW`` 74 - The filtered data was not read from the buffer in due time, 75 resulting in non-read data being lost. The buffer is flushed. 76 77 - - ``ETIMEDOUT`` 78 - The section was not loaded within the stated timeout period. 79 See ioctl :ref:`DMX_SET_FILTER` for how to set a timeout. 80 81 - - ``EFAULT`` 82 - The driver failed to write to the callers buffer due to an 83 invalid \*buf pointer. 84 85 86The generic error codes are described at the 87:ref:`Generic Error Codes <gen-errors>` chapter. 88