| .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later |
| .. c:namespace:: DTV.dmx |
| |
| .. _dmx_fread: |
| |
| ======================= |
| Digital TV demux read() |
| ======================= |
| |
| Name |
| ---- |
| |
| Digital TV demux read() |
| |
| Synopsis |
| -------- |
| |
| .. c:function:: size_t read(int fd, void *buf, size_t count) |
| |
| Arguments |
| --------- |
| |
| ``fd`` |
| File descriptor returned by a previous call to :c:func:`open()`. |
| |
| ``buf`` |
| Buffer to be filled |
| |
| ``count`` |
| Max number of bytes to read |
| |
| Description |
| ----------- |
| |
| This system call returns filtered data, which might be section or Packetized |
| Elementary Stream (PES) data. The filtered data is transferred from |
| the driver's internal circular buffer to ``buf``. The maximum amount of data |
| to be transferred is implied by count. |
| |
| .. note:: |
| |
| if a section filter created with |
| :c:type:`DMX_CHECK_CRC <dmx_sct_filter_params>` flag set, |
| data that fails on CRC check will be silently ignored. |
| |
| Return Value |
| ------------ |
| |
| On success 0 is returned. |
| |
| On error -1 is returned, and the ``errno`` variable is set |
| appropriately. |
| |
| .. tabularcolumns:: |p{2.5cm}|p{15.0cm}| |
| |
| .. flat-table:: |
| :header-rows: 0 |
| :stub-columns: 0 |
| :widths: 1 16 |
| |
| - - ``EWOULDBLOCK`` |
| - No data to return and ``O_NONBLOCK`` was specified. |
| |
| - - ``EOVERFLOW`` |
| - The filtered data was not read from the buffer in due time, |
| resulting in non-read data being lost. The buffer is flushed. |
| |
| - - ``ETIMEDOUT`` |
| - The section was not loaded within the stated timeout period. |
| See ioctl :ref:`DMX_SET_FILTER` for how to set a timeout. |
| |
| - - ``EFAULT`` |
| - The driver failed to write to the callers buffer due to an |
| invalid \*buf pointer. |
| |
| The generic error codes are described at the |
| :ref:`Generic Error Codes <gen-errors>` chapter. |
