Initialize EyeLink Library

Macros
#define	LINK_INITIALIZE_FAILED   -200
#define	CONNECT_TIMEOUT_FAILED   -201
#define	WRONG_LINK_VERSION   -202
#define	TRACKER_BUSY   -203

Functions
UINT16	open_eyelink_system (UINT16 bufsize, char FARTYPE *options)
void	eyelink_set_name (char FARTYPE *name)
void	close_eyelink_system (void)
INT16	eyelink_open_node (ELINKADDR node, INT16 busytest)
INT16	eyelink_open (void)
INT16	eyelink_broadcast_open (void)
INT16	eyelink_dummy_open (void)
INT16	eyelink_close (INT16 send_msg)
INT16	eyelink_is_connected (void)
INT16	eyelink_quiet_mode (INT16 mode)
INT16	eyelink_poll_trackers (void)
INT16	eyelink_poll_remotes (void)
INT16	eyelink_poll_responses (void)
INT16	eyelink_get_node (INT16 resp, void FARTYPE *data)
INT16	eyelink_get_tracker_version (char FARTYPE *c)
void	eyelink_set_tracker_node (ELINKADDR node)
INT16	open_eyelink_connection (INT16 mode)
void	close_eyelink_connection (void)
INT16	set_eyelink_address (char *addr)
void	eyelink_set_special_keys (int terminate_key_mask, int terminate_key, int break_key_mask, int break_key, int case_sensitive)
void	eyelink_set_special_keys_ex (int option, int *key_mask, int *key, int case_sensitive)
void	eyelink_get_special_keys_ex (int option, int *key_mask, int *key, int *case_sensitive)

Variables
ELINKADDR	eye_broadcast_address
ELINKADDR	rem_broadcast_address
ELINKADDR	our_address

Detailed Description

These methods are used to initialize the EyeLink Library.

Macro Definition Documentation

#define CONNECT_TIMEOUT_FAILED   -201

CONNECTION ERROR CODES: timed out waiting for reply

#define LINK_INITIALIZE_FAILED   -200

CONNECTION ERROR CODES: can't use link

#define TRACKER_BUSY   -203

CONNECTION ERROR CODES: tracker already connected

#define WRONG_LINK_VERSION   -202

CONNECTION ERROR CODES: wrong TSR or source version

Function Documentation

void close_eyelink_connection

(

void

)

Closes any connection to the eye tracker, and closes the link.

Remarks

NEW (v2.1): Broadcast connections can be closed, but not to affect the eye tracker. If a non-broadcast (primary) connection is closed, all broadcast connections to the tracker are also closed.

Example: See open_eyelink_connection()

See also

open_eyelink_connection() and eyelink_close()

void close_eyelink_system

(

void

)

Resets the EyeLink library, releases the system resources used by the millisecond clock.

Remarks

MUST DO BEFORE EXITING.

Example: See open_eyelink_system()

See also

open_eyelink_system(), eyelink_close() and set_offline_mode()

INT16 eyelink_broadcast_open

(

void

)

Allows a third computer to listen in on a session between the eye tracker and a controlling remote machine. This allows it to receive data during recording and playback, and to monitor the eye tracker mode. The local computer will not be able to send commands to the eye tracker, but may be able to send messages or request the tracker time.

Remarks

May not function properly, if there are more than one Ethernet cards installed.

Returns

0 if successful.
LINK_INITIALIZE_FAILED if link could not be established.
CONNECT_TIMEOUT_FAILED if tracker did not respond.
WRONG_LINK_VERSION if the versions of the EyeLink library and tracker are incompatible.
Example:

// This program illustrates the use of eyelink_broadcast_open(); see the COMM_SIMPLE and
// BROADCAST templates for more examples

#include <eyelink.h>
#include <stdio.h>

// Initialize the EyeLink DLL
if(open_eyelink_connection(-1))
    return -1;

// set our network name
eyelink_set_name("Broadcast");

...
// Extra code here to check for the tracker status or
// wait for the go-signal from the other application

// Starts the broadcast connection to the tracker
if(eyelink_broadcast_open())
{
    printf("Cannot open broadcast connection to tracker");
    return -1;
}

// enable link data reception by EyeLink DLL
eyelink_reset_data(1);
// NOTE: this function can discard some link data
eyelink_data_switch(RECORD_LINK_SAMPLES | RECORD_LINK_EVENTS);

See also

eyelink_close(), eyelink_dummy_open(), eyelink_is_connected(), eyelink_open() and eyelink_open_node()

INT16 eyelink_close

(

INT16

send_msg

)

Sends a disconnect message to the EyeLink tracker, resets the link data system.

Parameters

send_msg

Usually <send_msg> is 1. However, 0 can be used to reset the eyelink system if it is listening on a broadcast session.

Returns

0 if successful, otherwise link error.

Example:

// This program illustrates the use of eyelink_close

#include <eyelink.h>

// Checks whether the tracker is still connected
if(eyelink_is_connected())
{
   set_offline_mode();              // off-line mode
   eyecmd_printf("close_data_file");
   eyelink_close(1);         // disconnect from tracker
}

See also

eyelink_broadcast_open(), eyelink_open(), eyelink_dummy_open() and eyelink_open_node()

INT16 eyelink_dummy_open

(

void

)

Sets the EyeLink library to simulate an eyetracker connection. Functions will return plausible values, but no data.

Remarks

The function eyelink_is_connected() will return -1 to indicate a simulated connection.

Returns

Always returns 0.

Example:

// This program illustrates the use of eyelink_dummy_open

#include <eyelink.h>

// Initialize the EyeLink DLL; otherwise the application will crash
// when using the eyelink_dummy_open()function!
if(open_eyelink_connection(-1))
    return -1;

// Opens a "dummy" connection for debugging the application
eyelink_dummy_open();

See also

eyelink_broadcast_open(), eyelink_open() and eyelink_open_node()

INT16 eyelink_get_node	(	INT16	resp,
		void FARTYPE *	data
	)

Reads the responses returned by other trackers or remotes in response to eyelink_poll_trackers() or eyelink_poll_remotes(). It can also read the tracker broadcast address and remote broadcast addresses.

Parameters

resp	Nmber of responses to read:0 gets our data, 1 get first response, 2 gets the second response, etc. -1 to read the tracker broadcast address. -2 to read remote broadcast addresses.
data	Pointer to buffer of ELINKNODE type, to hold name and ELINKADDR of the respondent.

Returns

0 if OK, -1 if node response number is too high.

Example: See eyelink_poll_remotes()

See also

eyelink_node_receive(), eyelink_node_send() and eyelink_poll_remotes()

void eyelink_get_special_keys_ex	(	int	option,
		int *	key_mask,
		int *	key,
		int *	case_sensitive
	)

Gets the alternative extra special keys using option value that was previously set.

Parameters

option	. To indicate which function the special key set to
key_mask	reference to an array of mask values that is used for the provided option.
key	reference to an array of key charecter values that is used for the provided option.
case_sensitive	flag reference to case sensitive \param[in] option \c 1 especial key for drift correct skip

Example:

// Gets the EyeLink special keys
int drift_skip_key[4];
eyelink_get_special_keys_ex(1, 0, drift_skip_key, 0);

Output:

MSG 2248248 Newapplication

See also

eyelink_get_node(), open_eyelink_connection() and set_eyelink_address()

INT16 eyelink_get_tracker_version

(

char FARTYPE *

c

)

After connection, determines if the connected tracker is an EyeLink I or II.

Remarks

For the EyeLink II tracker, it can optionally retrieve the tracker software version.

Parameters

c	NULL, or pointer to a string (at least 40 characters) to hold the version string. This will be "EYELINK I" or "EYELINK II x.xx", where "x.xx" is the software version.

Returns

0 if not connected, 1 for EyeLink I, 2 for EyeLink II, 3 for EyeLink 1000, and 4 for EyeLink 3.

Example:

// This program illustrates the use of eyelink_get_tracker_version

#include <eyelink.h>

int i;
char version_info[256];

i = eyelink_get_tracker_version(version_info);
eyemsg_printf("EyeLink %d version %s", i, version_info);

Output:

MSG 500850 EyeLink 2 version EYELINK II 1.10

INT16 eyelink_is_connected

(

void

)

Checks whether the connection to the tracker is alive.

Remarks

Call this routine during loops and wherever the experiment might lock up if the tracker is shut down. Exit the experiment (by terminating loops and returning from all calls) if this returns 0.

Returns

0 if link closed.
-1 if simulating connection.
1 for normal connection.
2 for broadcast connection (NEW for v2.1 and later).
Example:

// This program illustrates the use of eyelink_is_connected( when performing a pre-trial drift correction

#include <eyelink.h>

while(1)
{
    // Checks link often so we can exit if tracker stopped
    if(!eyelink_is_connected())
        return ABORT_EXPT;

    // Performs drift correction with target drawn in the center
    error = do_drift_correct(SCRWIDTH/2, SCRHEIGHT/2, 1, 1);

    // repeat if ESC was pressed to access Setup menu
    if(error!=27) break;
}

See also

eyelink_close() and eyelink_open()

INT16 eyelink_open

(

void

)

Attempts to open a link connection to the EyeLink tracker. Simple connect to single EyeLink tracker. Equivalent to eyelink_open_node(broadcast_address, 0).

Remarks

The tracker address can be set by calling the function set_eyelink_address(). If this address was "255.255.255.255" the call to eyelink_open() will "broadcast" a request to any tracker, however this may fail if multiple Ethernet cards are installed. For the broadcast option to work use EyeLink I v2.1 or higher, EyeLink II v1.1 or higher. Before using this command, call either open_eyelink_connection(-1) or open_eyelink_system () to prepare the link for use.

Returns

0 if successful.
LINK_INITIALIZE_FAILED if link could not be established.
CONNECT_TIMEOUT_FAILED if tracker did not respond.
WRONG_LINK_VERSION if the versions of the EyeLink library and tracker are incompatible.
Example:

// This program illustrates the use of eyelink_open()

#include <eyelink.h>

// Initialize the EyeLink DLL
if(open_eyelink_connection(-1))
    return -1;

// Set the address of the tracker
set_eyelink_address("100.1.1.1");

// connect to single EyeLink tracker
if (eyelink_open())
    return -1;

See also

eyelink_broadcast_open(), eyelink_close(), eyelink_dummy_open(), eyelink_open_node(), open_eyelink_connection(), open_eyelink_system() and set_eyelink_address()

INT16 eyelink_open_node	(	ELINKADDR	node,
		INT16	busytest
	)

Allows the computer to connect to tracker, where the tracker is on the same network.

Parameters

node	Must be an address returned by eyelink_poll_trackers() and eyelink_poll_responses() to connect to any tracker.
busytest	If non-zero the call to eyelink_open_node() will not disconnect an existing connection.

Returns

0 if successful.
LINK_INITIALIZE_FAILED if link could not be established.
CONNECT_TIMEOUT_FAILED if tracker did not respond.
WRONG_LINK_VERSION if the versions of the EyeLink library and tracker are incompatible.
TRACKER_BUSY if <busytest> is set, and tracker is connected to another computer.
Example:

// This program illustrates the case of making connection using an ELINKADDR tracker node address

ELINKADDR node;                             // EyeLink address node

// Initialize the EyeLink DLL
if(open_eyelink_connection(-1))
    return -1;

// Converts tracker IP address to an EyeLink node
text_to_elinkaddr("100.1.1.1", node, 0);

// Makes connection using an ELINKADDR tracker node address; checks
// whether the tracker is already connected with another application
if (eyelink_open_node(node, 1))
    return -1;

See also

eyelink_node_receive(), eyelink_node_send(), eyelink_node_send_message() and eyelink_open()

INT16 eyelink_poll_remotes

(

void

)

Asks all non-tracker computers (with EyeLink software running) on the network to send their names and node address.

Returns

OK_RESULT if successful, otherwise link error.

LINK_TERMINATED_RESULT if link error.

-1 if broadcast option is not available.

Example:

// This program illustrates the use of eyelink_poll_remotes(). See COMM_SIMPLE/COMM_LISTENER
// templates for the complete example

#include <eyelink.h>

ELINKADDR listener_address;  // Address of listener application

// Finds the listener application
int check_for_listener(void)
{
    int i, n;
    ELINKNODE node;  // This will hold application name and address

    eyelink_poll_remotes(); // Polls network for EyeLink applications
    pump_delay(500);        // Gives applications time to respond

    n = eyelink_poll_responses();  // How many responses?
    //  Responses 1 to n are from other applications
    for(i = 1; i<= n; i++)
    {
        if(eyelink_get_node(i, &node) < 0)
            return -1;  // error: no such data

        // Found the "Comm_listener" application
        if(!_stricmp(node.name, "comm_listener"))
        {
            // Stores the listener's address
            memcpy(listener_address, node.addr, sizeof(ELINKADDR));

            // Send a message to the listener
            eyelink_node_send(listener_address, "NAME comm_simple", 40);

            ...
            // Other code here to check responses from the listener
            ...

            return 0;   // all communication checks out
        }
    }
    return -1;    // no listener node found
}

See also

eyelink_poll_responses() and eyelink_poll_trackers()

INT16 eyelink_poll_responses

(

void

)

Returns the count of node addresses received so far following the call of eyelink_poll_remotes() or eyelink_poll_trackers().

Remarks

You should allow about 100 milliseconds for all nodes to respond. Up to 4 node responses are saved.

Returns

Number of nodes responded. 0 if no responses.

Example: See eyelink_poll_remotes()

See also

eyelink_poll_remotes() and eyelink_poll_trackers()

INT16 eyelink_poll_trackers

(

void

)

Asks all trackers (with EyeLink software running) on the network to send their names and node address.

Returns

OK_RESULT if successful, otherwise link error.

LINK_TERMINATED_RESULT if link error.

-1 if broadcast option is not available.

Example: See eyelink_poll_remotes()

See also

eyelink_poll_remotes() and eyelink_poll_responses()

INT16 eyelink_quiet_mode

(

INT16

mode

)

Controls the level of control an application has over the tracker.

Remarks

This is used in combination with broadcast mode (multiple applications connected to one tracker) to ensure that "listener" applications do not inadvertently send commands, key presses, or messages to the tracker. This is mostly useful when quickly converting an existing application into a listener.

Parameters

mode	0 to allow all communication. 1 to block commands (allows only key presses, messages, and time or variable read requests). 2 to disable all commands, requests and messages. -1 to just return current setting.

Returns

The previous settings.

Example:

// This program illustrates the use of eyelink_quiet_mode() to control message sending from a Broadcast
// application to the tracker

#include <eyelink.h>
#include <stdio.h>

// Starts the broadcast connection to the tracker
if(eyelink_broadcast_open())
{
    printf("Cannot open broadcast connection to tracker");
    return -1;
}

// enable link data reception by EyeLink DLL
eyelink_reset_data(1);
// NOTE: this function can discard some link data
eyelink_data_switch(RECORD_LINK_SAMPLES | RECORD_LINK_EVENTS);

// The following codes test the message sending from the BROADCAST
// application to tracker with eyelink_quiet_mode()
eyelink_quiet_mode(0);      // Allows for message sending
eyelink_send_message("This should be recorded in the EDF file");
eyelink_quiet_mode(2);   // Disables message sending
eyelink_send_message("This should not appear in the EDF file");
eyelink_quiet_mode(0);   // Allows for message sending again
eyelink_send_message("This should appear in the EDF file");

Output:

MSG 3304947 This message should be recorded in the EDF file
MSG 3304947 This message should appear in the EDF file

See also

eyelink_broadcast_open() and eyelink_open()

void eyelink_set_name

(

char FARTYPE *

name

)

Sets the node name of this computer (up to 35 characters).

Parameters

name	String to become new name.

Example:

// This program illustrates the use of eyelink_set_name()
#include <eyelink.h>

ELINKNODE node;  // This will hold application name and address

// Sets the EyeLink host address, if tracker IP address is different
// from the default "100.1.1.1"
if (set_eyelink_address("100.1.1.7"))
    return -1;

// Initializes EyeLink library, and opens connection to the tracker
if(open_eyelink_connection(0))
    return -1;

// set our EyeLink node name
eyelink_set_name("Newapplication");

// Verify the name set by getting copy of node data
// Since we are checking our own data, set resp = 0
if(eyelink_get_node(0, &node) == OK_RESULT)
    eyemsg_printf("%s", node.name);

Output:

MSG 2248248 Newapplication

See also

eyelink_get_node(), open_eyelink_connection() and set_eyelink_address()

void eyelink_set_special_keys	(	int	terminate_key_mask,
		int	terminate_key,
		int	break_key_mask,
		int	break_key,
		int	case_sensitive
	)

Sets the alternative for special keys such as CTRL+C, ESC

Parameters

terminate_key_mask	mask value for the terminate key
terminate_key	Terminate key charecter key that terminate the eyelink applicaiton
break_key_mask	mask value for the break key
break_key	Break key charecter key that terminate the eyelink applicaiton
case_sensitive	flag 1 means case sensitive 0 means not case sensitive

Example:

// This program illustrates the use of eyelink_set_special_keys()
#include <core_expt.h>
Eg. CTRL key can be
ELKMOD_NONE   0x0000 - Modifier for KeyInput.modifier; No modifier present
ELKMOD_LSHIFT 0x0001 - Modifier for KeyInput.modifier; Left shift
ELKMOD_RSHIFT 0x0002 - Modifier for KeyInput.modifier; Right shift
ELKMOD_LCTRL  0x0040 - Modifier for KeyInput.modifier; left conrol
ELKMOD_RCTRL  0x0080 - Modifier for KeyInput.modifier; Right control
ELKMOD_LALT   0x0100 - Modifier for KeyInput.modifier; Left Alt
ELKMOD_RALT   0x0200 - Modifier for KeyInput.modifier; Right alt
ELKMOD_LMETA  0x0400 - Modifier for KeyInput.modifier; Left Meta
ELKMOD_RMETA  0x0800 - Modifier for KeyInput.modifier; Right Meta
ELKMOD_NUM    0x1000 - Modifier for KeyInput.modifier; Number lock key
ELKMOD_CAPS   0x2000 - Modifier for KeyInput.modifier; Cap lock key
ELKMOD_MODE   0x4000 - Modifier for KeyInput.modifier; Mode key

ELINKNODE node;  // This will set and overwrite the default special keys CTRL+C and ESC

// Sets the EyeLink special keys
// from the default CTRL, C and ESC to provided values
if (eyelink_set_special_keys(ELKMOD_LCTRL, 'C', ELKMOD_RSHIFT, 'Q', 0))
    return -1;

Output:

MSG 2248248 Newapplication

See also

eyelink_get_node(), open_eyelink_connection() and set_eyelink_address()

void eyelink_set_special_keys_ex	(	int	option,
		int *	key_mask,
		int *	key,
		int	case_sensitive
	)

Sets the alternative for extra special keys such as CTRL+C, ESC for drift correct skip, etc.

Parameters

option	. To indicate which function the special key set to
key_mask	A list of mask values that is used for the provided option. An array of 4 int are supported.
key	A list of key charecter key values that is used for the provided option. An array of 4 int are supported.
case_sensitive	flag 1 means case sensitive 0 means not case sensitive \param[in] option \c 1 especial key for drift correct skip \c 2 especial key for drift correct accept

Example:

// This program illustrates the use of eyelink_set_special_keys_ex()
#include <core_expt.h>
Eg. CTRL key can be
ELKMOD_NONE   0x0000 - Modifier for KeyInput.modifier; No modifier present
ELKMOD_LSHIFT 0x0001 - Modifier for KeyInput.modifier; Left shift
ELKMOD_RSHIFT 0x0002 - Modifier for KeyInput.modifier; Right shift
ELKMOD_LCTRL  0x0040 - Modifier for KeyInput.modifier; left conrol
ELKMOD_RCTRL  0x0080 - Modifier for KeyInput.modifier; Right control
ELKMOD_LALT   0x0100 - Modifier for KeyInput.modifier; Left Alt
ELKMOD_RALT   0x0200 - Modifier for KeyInput.modifier; Right alt
ELKMOD_LMETA  0x0400 - Modifier for KeyInput.modifier; Left Meta
ELKMOD_RMETA  0x0800 - Modifier for KeyInput.modifier; Right Meta
ELKMOD_NUM    0x1000 - Modifier for KeyInput.modifier; Number lock key
ELKMOD_CAPS   0x2000 - Modifier for KeyInput.modifier; Cap lock key
ELKMOD_MODE   0x4000 - Modifier for KeyInput.modifier; Mode key

ELINKNODE node;  // This will set and overwrite the default special keys CTRL+C and ESC

  int F4[4] = { 15872, 0, 0,0};
  int F5[4] = { 16128, 0, 0,0 };
  int mask[4] = { 0,0,0,0 };
  eyelink_set_special_keys_ex(1, (int *) mask, (int *)F4, 0);
  eyelink_set_special_keys_ex(2, mask, F5, 0);

Output:

MSG 2248248 Newapplication

See also

eyelink_get_node(), open_eyelink_connection() and set_eyelink_address()

void eyelink_set_tracker_node

(

ELINKADDR

node

)

Address used for non-connected time requests and message sends. the "proper" way to do this is with the "node" type of functions but we allow a "back door" to simplify higher level support functions. This is also the address used under Windows for looking for tracker (an IP broadcast is used on all other platforms). There is a bug in the Windows networking, causing broadcasts sent on all cards to have the IP source addres of only the first card. This means the tracker sends its connection reply to the wrong address. So the exact address or a subnet broadcast address (i.e. 100.1.1.255 for a subnet mask of 255.255.255.0) needs to be set to that of the tracker.

INT16 open_eyelink_connection

(

INT16

mode

)

Initializes the EyeLink library, and opens a connection to the EyeLink tracker.

Remarks

By setting <mode> to be 1, the connection can be simulated for debugging purposes. Only timing operations and simple tests should be done in simulation mode. This function is intended for networks where a single tracker is connected to the network. By setting <mode> to be 2, the connection is made to the master application instead of the tracker directly. The master and slave application needs to run on the same machine. If the master and slave needs to run on different machines, please see eyelink_broadcast_open().

The slave application can send messages and read variable values from the eyelink tracker. However, it cannot send any commands to the tracker nor open or close edf files. Camera setup image previewing is not suppored in slave mode. The messasges that are sent by the slave application will be save in the edf file that was created by the master application.

@param mode Mode of connection:
                            \arg \c 0  Opens a connection with the eye tracker.
                            \arg \c 1  Creates a dummy connection for simulation.
                            \arg \c -1 Initializes the DLL but does not open a connection.
                            \arg \c 2 Create a slave connection to recieve data from a master eyelink application.
                            \arg \c 3 Opens a connection to the eye tracker and setup master configuration for the slave application to connect.
@return \c 0 if success, else error code

\b Example 1:
This program illustrates the use of open_eyelink_connection() for a regular eyelink application

#include <core_expt.h>

// Sets the EyeLink host address, if tracker IP address is different
// from the default "100.1.1.1"
if (set_eyelink_address("100.1.1.7"))
    return -1;

//Initializes EyeLink library, and opens connection to the tracker
if(open_eyelink_connection(0))
    return -1;

...
// Code for the setup, recording, and cleanups
close_eyelink_connection();      // disconnect from tracker

Example 2: This program illustrates the use of open_eyelink_connection() for a regular eyelink application that allows to server as the master application for another slave application.

#include <core_expt.h>

// set the time base to local machine so that both the master and slave are on the same time base
eyelink_set_clock_base(SR_CLOCK_BASE_MACHINE_LOCAL);

// Sets the EyeLink host address, if tracker IP address is different
// from the default "100.1.1.1"
if (set_eyelink_address("100.1.1.7"))
    return -1;

//Initializes EyeLink library, and opens connection to the tracker and setup master mode
if(open_eyelink_connection(3))
    return -1;

...
// Code for the setup, recording, and cleanups
close_eyelink_connection();      // disconnect from tracker

Example 3: This program illustrates an eyelink salve application. Any regular eyelink application, can be connverted to a master application by calling the following functions as descibed above.

eyelink_set_clock_base(SR_CLOCK_BASE_MACHINE_LOCAL);
open_eyelink_connection(3);

For this to work, a master application needs to be running at the time of execution.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef __APPLE__
#include <eyelink_core/core_expt.h>
#else
#include <core_expt.h>
#endif

void monitor_connection()
{

    // In this function we reset the eyelink qdata and wait for the master application
    // to switch to record mode. When it switches to record mode, we collect the samples
    // and print them
    ALLF_DATA evt;
    eyelink_reset_data(1);
    eyelink_data_switch(RECORD_LINK_SAMPLES | RECORD_LINK_EVENTS);
    while(1)    // loop while in record mode
    {
            int tmode =eyelink_tracker_mode();
            if( tmode== EL_RECORD_MODE)
            {
                                     // CODE FOR PLOTTING GAZE CURSOR
                    if(eyelink_newest_float_sample(NULL)>0)  // new sample?
                    {
                            eyelink_newest_float_sample(&evt);  // get the sample data
                            printf("Sample %d %f %f %f %f\r",evt.fs.time, evt.fs.gx[0],evt.fs.gy[0],evt.fs.gx[1],evt.fs.gy[1]);
                    }
            }
            else
            {
                    printf("Waiting for start Recording. currently %d \r", tmode);
                    usleep(1000);

            }
            if(!eyelink_is_connected()) return ;
    }
}

int main(int argc, char ** argv)
{
    // set the time base to local machine so that both the master and slave are on the same time base
    eyelink_set_clock_base(SR_CLOCK_BASE_MACHINE_LOCAL);

    //Initializes EyeLink library, and opens connection to a maseter application
    if(open_eyelink_connection(2)!=0)
    {
            printf("Failed to connect to tracker \n");
            return 0;
    }

    //Send an eyelink message. Since we are connecting to a master application,
    // this message will show up in the edf file that was opened by the master application.
    // Note, here we did not open any edf files.
    eyemsg_printf("SLAVE message 1");

    // Read screen_pixel_coords from the host.
    {
            UINT32 t;
            char buf[100] = "";
            printf("Reading screen pixel coords\n");
            eyelink_read_request("screen_pixel_coords");

            t = current_msec();
            while(current_msec()-t < 500)
            {
              if(eyelink_read_reply (buf) == OK_RESULT)
              {
                      float left,top,right, bottom;
                      if(sscanf(buf, "%f,%f,%f,%f", &left,&top,&right,&bottom)==4)
                      {
                                    printf("Size %f %f %f %f \n", left, top, right ,bottom);
                                    break;
                      }
              }
            }
    }

    // Collect eyelink data from host via master application.
    monitor_connection();
    usleep(50000);// allow host to finish with the messages.
    close_eyelink_system(); // disconnect from tracker
    return 1;
}

See also

close_eyelink_connection(), close_eyelink_system(), eyelink_broadcast_open(), eyelink_dummy_open(), eyelink_open() and eyelink_open_node()

UINT16 open_eyelink_system	(	UINT16	bufsize,
		char FARTYPE *	options
	)

Use this function to initialize the EyeLink library. This will also start the millisecond clock. No connection is attempted to the eyetracker yet. It is preferable to call open_eyelink_connection(-1) instead, as this prepares other parts of the DLL for use.

Remarks

MUST BE FIRST CALL TO LINK INTERFACE.

Parameters

bufsize	Size of sample buffer. 60000 is the maximum allowed. (0 for default)
options	Text specifying initialization options. Currently no options are supported. (NULL or "" for defaults)

Returns

0 if failed, nonzero (-1 or TSR SWI number) if success.

Example:

// This program shows the use of open_eyelink_system() and close_eyelink_system ()

#include <eyelink.h>
int dummy = 0;  // Sets the connection type

// Initialize the EyeLink library
if(!open_eyelink_system(0, ""))
{
    printf("\nERROR: Cannot initialize eyelink library\n");
    return -1;
}

if(dummy)
    i = eyelink_dummy_open(); // Starts a dummy connection
else
    i = eyelink_open();  // Connects to the tracker

...
// Code for the setup, recording, and cleanups

// Now, the following code closes the eyelink connection
// Checks whether we still have the connection to the tracker
if(eyelink_is_connected())
{
    // Places EyeLink tracker in off-line (idle) mode
    set_offline_mode();
    eyecmd_printf("close_data_file");    // close data file
    eyelink_close(1);         // disconnect from tracker
}

// shut down system (MUST do before exiting)
close_eyelink_system();

See also

close_eyelink_connection(), close_eyelink_system(), eyelink_close() and eyelink_open()

INT16 set_eyelink_address

(

char *

addr

)

Sets the IP address used for connection to the EyeLink tracker. This is set to "100.1.1.1" in the DLL, but may need to be changed for some network configurations. This must be set before attempting to open a connection to the tracker.

Remarks

A "broadcast" address ("255.255.255.255") may be used if the tracker address is not known - this will work only if a single Ethernet card is installed, or if DLL version 2.1 or higher, and the latest tracker software versions (EyeLink I v2.1 or higher, EyeLink II v1.1 or higher, all version of EyeLink 1000, 1000 Plus, and Portable Duo) are installed.

Parameters

addr	Pointer to a string containing a "dotted" 4-digit IP address.

Returns

0 if success, -1 if could not parse address string.

Example:

// This program illustrates the use of set_eyelink_address()

#include <core_expt.h>

// Initialize the EyeLink DLL
if(open_eyelink_connection(-1))
    return -1;

// Set the address of the tracker
set_eyelink_address("100.1.1.1");

// connect to single EyeLink tracker
if (eyelink_open())
    return -1;

See also

eyelink_open(), eyelink_open_node(), text_to_elinkaddr()

Variable Documentation

ELINKADDR eye_broadcast_address

The broadcast address for the eye trackers.

ELINKADDR our_address

This EyeLink node's address for the link implementation.

ELINKADDR rem_broadcast_address

The broadcast address for the remotes.