imgSessionWaitSignalAsync2

Usage

rval imgSessionWaitSignalAsync2(SESSION_ID sid, IMG_SIGNAL_TYPE signalType, uInt32 signalIdentifier, uInt32 state, CALL_BACK_PTR2 function, void* data);

Purpose

Waits for a signal to be in a given state and when the signal is in that state, calls a user-defined function.

Parameters

Name	Type	Direction
sid	SESSION_ID	input
signalType	IMG_SIGNAL_TYPE	input
signalIdentifier	uInt32	input
state	uInt32	input
function	CALL_BACK_PTR	input
data	void*	input
rval	Int32	output

Parameter Discussion

sid: valid SESSION_ID.

signalType: type of signal to wait for. The signal can be one of the following constants:

Note  To use the ISO_IN or RS422_IN signals on the NI PCI-1426, select External as the Trigger Type for your function and choose ISO In or RS-422 In as the Signal Level for the trigger line in Measurement & Automation Explorer (MAX).

IMG_SIGNAL_EXTERNAL

IMG_SIGNAL_RTSI

IMG_SIGNAL_ISO_IN

IMG_SIGNAL_ISO_OUT

IMG_SIGNAL_STATUS

signalIdentifier: is the signal identifier. If the signal type is one of the triggers, then this value specifies which trigger line. If the signal type is IMG_SIGNAL_STATUS, signalIdentifier must be one of the following constants:

IMG_AQ_DONE

IMG_AQ_IN_PROGRESS

IMG_BUF_COMPLETE

IMG_FRAME_DONE

IMG_FRAME_START

state: state of the signal to wait for. state can be one of the following constants:

IMG_SIGNAL_STATE_RISING	Waits for a rising edge.
IMG_SIGNAL_STATE_FALLING	Waits for a falling edge.
IMG_SIGNAL_STATE_HIGH	Returns immediately if the signal is high. Otherwise, waits for a rising edge.
IMG_SIGNAL_STATE_LOW	Returns immediately if the signal is low. Otherwise, waits for a falling edge.

function: pointer to the callback function. Your function should match the following prototype:

uInt32(*function)(SESSION_ID sid, IMG_ERR err, IMG_SIGNAL_TYPE signalType, uInt32 signalIdentifier, void* userdata)

Note  The return value of the callback function determines the behavior of the driver for subsequent signal assertions. Return zero to disregard future signal assertions. Return a non-zero value to continue to receive callbacks.

data value that is passed to the callback function. The value can be a pointer to user data.

Return Value

This function returns 0 on success. On failure, this function returns an error code. For information about the error code, call imgShowError.