Feature reports are sent over the Control endpoint as a
Set_Report transfer. The first byte of @p data[] must
contain the Report ID. For devices which only support a
single report, this must be set to 0x0. The remaining bytes
contain the report data. Since the Report ID is mandatory,
calls to hid_send_feature_report() will always contain one
more byte than the report contains. For example, if a hid
report is 16 bytes long, 17 bytes must be passed to
hid_send_feature_report(): the Report ID (or 0x0, for
devices which do not use numbered reports), followed by the
report data (16 bytes). In this example, the length passed
in would be 17.
@ingroup API
@param device A device handle returned from hid_open().
@param data The data to send, including the report number as
the first byte.
@param length The length in bytes of the data to send, including
the report number.
@returns
This function returns the actual number of bytes written and
-1 on error.
@brief Send a Feature report to the device.
Feature reports are sent over the Control endpoint as a Set_Report transfer. The first byte of @p data[] must contain the Report ID. For devices which only support a single report, this must be set to 0x0. The remaining bytes contain the report data. Since the Report ID is mandatory, calls to hid_send_feature_report() will always contain one more byte than the report contains. For example, if a hid report is 16 bytes long, 17 bytes must be passed to hid_send_feature_report(): the Report ID (or 0x0, for devices which do not use numbered reports), followed by the report data (16 bytes). In this example, the length passed in would be 17.
@ingroup API @param device A device handle returned from hid_open(). @param data The data to send, including the report number as the first byte. @param length The length in bytes of the data to send, including the report number.
@returns This function returns the actual number of bytes written and -1 on error.