Function libeyelink_sys::eyelink_newest_double_sample

pub unsafe extern "C" fn eyelink_newest_double_sample(buf: *mut c_void) -> INT16

@ingroup messaging Check if a new sample has arrived from the link. This is the latest sample, not the oldest sample that is read by \c eyelink_get_next_data(), and is intended to drive gaze cursors and gaze-contingent displays. Typically the function is called with a \c NULL buffer pointer, to test if new data has arrived. If a value of \c 1 is returned, the function is called with a \c DSAMPLE buffer to get the new sample.

@param buf Pointer to sample buffer type \c DSAMPLE. If \c NULL, just checks new-sample status. @return \c -1 if no samples, \c 0 if no new data, \c 1 if new sample.

\sa \c eyelink_get_float_data(), \c eyelink_get_last_data(), \c eyelink_get_next_data(), \c eyelink_get_sample() \c eyelink_newest_float_sample() and \c eyelink_newest_sample()