Function libeyelink_sys::eyelink_read_request

pub unsafe extern "C" fn eyelink_read_request(text: *mut c_char) -> INT16

@ingroup messaging Sends a text variable name whose value is to be read and returned by the tracker as a text string.

@remarks NEW (v2.1): If the link is initialized but not connected to a tracker, the message will be sent to the tracker set by \c set_eyelink_address(). However, these requests will be ignored by tracker versions older than EyeLink I v2.1 and EyeLink II v1.1. @param text String with message to send. @return \c 0 if success, otherwise link error code.

\b Example:

\code

int read_tracker_pixel_coords(void)
{
char buf[100] = "";
UINT32 t;

if(!eyelink_is_connected() || break_pressed())
return 1;

eyelink_read_request("screen_pixel_coords");

t = current_msec();
while(current_msec()-t < 500)
{
if(eyelink_read_reply(buf) == OK_RESULT)
{
eyemsg_printf("%s", buf);
return 0;
}
message_pump(NULL);  // Keeps Windows happy
if(!eyelink_is_connected) return 1;
if(break_pressed()) return 1;
}
return -1;  // Timed out
}
\endcode

\b Output:

\code
MSG	374986 0.000000,0.000000,1023.000000,767.000000
\endcode

\sa \c eyelink_read_reply()