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.