18c2ecf20Sopenharmony_ci.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 28c2ecf20Sopenharmony_ci.. c:namespace:: DTV.dmx 38c2ecf20Sopenharmony_ci 48c2ecf20Sopenharmony_ci.. _dmx_fread: 58c2ecf20Sopenharmony_ci 68c2ecf20Sopenharmony_ci======================= 78c2ecf20Sopenharmony_ciDigital TV demux read() 88c2ecf20Sopenharmony_ci======================= 98c2ecf20Sopenharmony_ci 108c2ecf20Sopenharmony_ciName 118c2ecf20Sopenharmony_ci---- 128c2ecf20Sopenharmony_ci 138c2ecf20Sopenharmony_ciDigital TV demux read() 148c2ecf20Sopenharmony_ci 158c2ecf20Sopenharmony_ciSynopsis 168c2ecf20Sopenharmony_ci-------- 178c2ecf20Sopenharmony_ci 188c2ecf20Sopenharmony_ci.. c:function:: size_t read(int fd, void *buf, size_t count) 198c2ecf20Sopenharmony_ci 208c2ecf20Sopenharmony_ciArguments 218c2ecf20Sopenharmony_ci--------- 228c2ecf20Sopenharmony_ci 238c2ecf20Sopenharmony_ci``fd`` 248c2ecf20Sopenharmony_ci File descriptor returned by a previous call to :c:func:`open()`. 258c2ecf20Sopenharmony_ci 268c2ecf20Sopenharmony_ci ``buf`` 278c2ecf20Sopenharmony_ci Buffer to be filled 288c2ecf20Sopenharmony_ci 298c2ecf20Sopenharmony_ci``count`` 308c2ecf20Sopenharmony_ci Max number of bytes to read 318c2ecf20Sopenharmony_ci 328c2ecf20Sopenharmony_ciDescription 338c2ecf20Sopenharmony_ci----------- 348c2ecf20Sopenharmony_ci 358c2ecf20Sopenharmony_ciThis system call returns filtered data, which might be section or Packetized 368c2ecf20Sopenharmony_ciElementary Stream (PES) data. The filtered data is transferred from 378c2ecf20Sopenharmony_cithe driver’s internal circular buffer to ``buf``. The maximum amount of data 388c2ecf20Sopenharmony_cito be transferred is implied by count. 398c2ecf20Sopenharmony_ci 408c2ecf20Sopenharmony_ci.. note:: 418c2ecf20Sopenharmony_ci 428c2ecf20Sopenharmony_ci if a section filter created with 438c2ecf20Sopenharmony_ci :c:type:`DMX_CHECK_CRC <dmx_sct_filter_params>` flag set, 448c2ecf20Sopenharmony_ci data that fails on CRC check will be silently ignored. 458c2ecf20Sopenharmony_ci 468c2ecf20Sopenharmony_ciReturn Value 478c2ecf20Sopenharmony_ci------------ 488c2ecf20Sopenharmony_ci 498c2ecf20Sopenharmony_ciOn success 0 is returned. 508c2ecf20Sopenharmony_ci 518c2ecf20Sopenharmony_ciOn error -1 is returned, and the ``errno`` variable is set 528c2ecf20Sopenharmony_ciappropriately. 538c2ecf20Sopenharmony_ci 548c2ecf20Sopenharmony_ci.. tabularcolumns:: |p{2.5cm}|p{15.0cm}| 558c2ecf20Sopenharmony_ci 568c2ecf20Sopenharmony_ci.. flat-table:: 578c2ecf20Sopenharmony_ci :header-rows: 0 588c2ecf20Sopenharmony_ci :stub-columns: 0 598c2ecf20Sopenharmony_ci :widths: 1 16 608c2ecf20Sopenharmony_ci 618c2ecf20Sopenharmony_ci - - ``EWOULDBLOCK`` 628c2ecf20Sopenharmony_ci - No data to return and ``O_NONBLOCK`` was specified. 638c2ecf20Sopenharmony_ci 648c2ecf20Sopenharmony_ci - - ``EOVERFLOW`` 658c2ecf20Sopenharmony_ci - The filtered data was not read from the buffer in due time, 668c2ecf20Sopenharmony_ci resulting in non-read data being lost. The buffer is flushed. 678c2ecf20Sopenharmony_ci 688c2ecf20Sopenharmony_ci - - ``ETIMEDOUT`` 698c2ecf20Sopenharmony_ci - The section was not loaded within the stated timeout period. 708c2ecf20Sopenharmony_ci See ioctl :ref:`DMX_SET_FILTER` for how to set a timeout. 718c2ecf20Sopenharmony_ci 728c2ecf20Sopenharmony_ci - - ``EFAULT`` 738c2ecf20Sopenharmony_ci - The driver failed to write to the callers buffer due to an 748c2ecf20Sopenharmony_ci invalid \*buf pointer. 758c2ecf20Sopenharmony_ci 768c2ecf20Sopenharmony_ciThe generic error codes are described at the 778c2ecf20Sopenharmony_ci:ref:`Generic Error Codes <gen-errors>` chapter. 78