1.. -*- coding: utf-8; mode: rst -*- 2 3.. _lirc-write: 4 5************ 6LIRC write() 7************ 8 9Name 10==== 11 12lirc-write - Write to a LIRC device 13 14 15Synopsis 16======== 17 18.. code-block:: c 19 20 #include <unistd.h> 21 22 23.. c:function:: ssize_t write( int fd, void *buf, size_t count ) 24 :name: lirc-write 25 26Arguments 27========= 28 29``fd`` 30 File descriptor returned by ``open()``. 31 32``buf`` 33 Buffer with data to be written 34 35``count`` 36 Number of bytes at the buffer 37 38Description 39=========== 40 41:ref:`write() <lirc-write>` writes up to ``count`` bytes to the device 42referenced by the file descriptor ``fd`` from the buffer starting at 43``buf``. 44 45The exact format of the data depends on what mode a driver uses, use 46:ref:`lirc_get_features` to get the supported mode. 47 48When in :ref:`LIRC_MODE_PULSE <lirc-mode-PULSE>` mode, the data written to 49the chardev is a pulse/space sequence of integer values. Pulses and spaces 50are only marked implicitly by their position. The data must start and end 51with a pulse, therefore, the data must always include an uneven number of 52samples. The write function must block until the data has been transmitted 53by the hardware. If more data is provided than the hardware can send, the 54driver returns ``EINVAL``. 55 56Return Value 57============ 58 59On success, the number of bytes read is returned. It is not an error if 60this number is smaller than the number of bytes requested, or the amount 61of data required for one frame. On error, -1 is returned, and the ``errno`` 62variable is set appropriately. The generic error codes are described at the 63:ref:`Generic Error Codes <gen-errors>` chapter. 64