A VI has Automatic Error Handling enabled. It calls a SubVI that has Automatic Error Handling disabled and the Error Out terminal is unwired in the calling VI. The SubVI returns an error to the calling VI. Will an error dialog be posted?
A. Yes, since the SubVI has Automatic Error Handling disabled
B. No, since the SubVI has Automatic Error Handling disabled
C. No, since the Error Out terminal from the SubVI is not wired in the calling VI.
D. Yes, since the Error Out terminal from the SubVI is not wired in the calling VI.
Answer (2)
In this scenario, the main Virtual Instrument (VI) has Automatic Error Handling enabled, but the SubVI does not. The Automatic Error Handling mechanism in LabVIEW automatically displays an error dialog if an error is not handled or output from the VI.
Here's a step-by-step breakdown of what happens:
Main VI Settings: The main VI has Automatic Error Handling enabled. This means that if there is an unhandled error within the VI, LabVIEW will automatically display an error dialog.
SubVI Settings: The SubVI has Automatic Error Handling disabled, meaning it will not automatically show an error dialog on its own if it encounters an error.
Error Propagation: Even though the SubVI has Automatic Error Handling disabled, it still returns an error to the calling VI because the error is propagated through the VI hierarchy unless explicitly handled within the SubVI.
Wiring of Error Terminals: In the calling VI (main VI), the Error Out terminal of the SubVI is unwired. This implies that any error output from the SubVI isn't explicitly handled or wired to another VI or terminal in the main VI.
Automatic Error Handling Action: Since the main VI has Automatic Error Handling enabled and the error from the SubVI is not wired to an error out terminal or any further handling mechanism in the main VI, LabVIEW will automatically post an error dialog.
Thus, the correct multiple-choice option is:
Yes, since the Error Out terminal from the SubVI is not wired in the calling VI.
The automatic display of the error dialog is because the main VI's error handling settings take precedence when the error is not managed within the expanded hierarchy of VIs.
The main VI has Automatic Error Handling enabled and will display an error dialog if an error is propagated from the SubVI. The SubVI itself does not display an error since its Automatic Error Handling is disabled. The correct answer is A: Yes, since the SubVI has Automatic Error Handling disabled.
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