Notifiers .... notifiers .... everywhere

[SercoSteveB]

What are the contents of String Array Out following execution of the VI?

NOTE:  Multiple answers may apply.

[nik35324]

A B C D.

Notifiers are lossy, single element and broadcasting. Used to display data which are not time critical for eg. charts & graphsasin QMH template.

[simonj69]

ABC or D

[Timsrice]

A, or B, or C

I think the response is in 'build array' order, so I don't think D would occur.

(Please correct me if my understanding is wrong)

[MrStevenUND]

a, b, c, d.  

All are possible because we don't know the order of execution (race condition)

[crossrulz]

All

[Matt-A.]

All.  Interesting.  I am wondering about Tim's question.  So reading the Wait on Notification from Muliple indicates this snippet could cause deadlock.  If possible, the Wait...with Notifier History function would be the better choice. 

[ABCMan]

Can someone explain how C and D can be answers?  Wouldn't stop on True prevent the first loop getting to the second notifier?  

[Timsrice]

'Wait on notification from multiple' will fire when one of the notifiers receives a message.  It will then supply an array of all the current notifications.  On some occasions the other notifier has squeezed in before the 'Wait...' actually fires.
In this case there are two notifications.

Race condition

All loops execute just once

Sometimes both notifiers will have a message

[SercoSteveB]

Answer: A, B, C & D.  Nice one all.    The order of execution of the WHILE Loops is the key here as covered by MrStevenUND and Timsrice.

[Akhil_shah]

I tried this and my answer is A. Can someone explain how All will be the answer?

[crossrulz]

You have a race condition in that fact that you cannot guarantee which notifications will be sent and in what order before the Wait On Multiple Notifications is called.