5.3.1. LIRC read()¶
5.3.1.1. Name¶
lirc-read - Read from a LIRC device
5.3.1.3. Arguments¶
fd
- File descriptor returned by
open()
. buf
- Buffer to be filled
count
- Max number of bytes to read
5.3.1.4. Description¶
read() attempts to read up to count
bytes from file
descriptor fd
into the buffer starting at buf
. If count
is zero,
read() returns zero and has no other results. If count
is greater than SSIZE_MAX
, the result is unspecified.
The lircd userspace daemon reads raw IR data from the LIRC chardev. The exact format of the data depends on what modes a driver supports, and what mode has been selected. lircd obtains supported modes and sets the active mode via the ioctl interface, detailed at LIRC Function Reference. The generally preferred mode for receive is LIRC_MODE_MODE2, in which packets containing an int value describing an IR signal are read from the chardev.
See also http://www.lirc.org/html/technical.html for more info.
5.3.1.5. Return Value¶
On success, the number of bytes read is returned. It is not an error if
this number is smaller than the number of bytes requested, or the amount
of data required for one frame. On error, -1 is returned, and the errno
variable is set appropriately.