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Owning Palette: Notifier Operations Functions

Installed With: Base Package

Waits until a notifier receives a message.

When the notifier receives a message, this function continues to execute. Use the Send Notification function to send the message. If a notifier reference becomes invalid such as when another function closes it, the function stops waiting and returns error code 1122. If the notifier does not contain a message, this function waits until the notifier receives a message.

Details  

	notifier is a reference to a notifier. Use the Obtain Notifier function to obtain a notifier reference.
	ignore previous indicates whether to ignore messages that LabVIEW sends to the notifier before it calls this function. If TRUE and the notifier contains a message before you call this function, this function waits until the notifier receives another message. If FALSE (default) and the notifier contains a message before you call this function, this function continues to execute.
	timeout in ms indicates how many milliseconds the function waits for the notifier to receive a message. The default is –1, which indicates never to time out.If the function waits timeout in ms and the notifier does not receive a message, timed out? is TRUE.
	error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurred before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use exception control to treat what is normally an error as no error or to treat a warning as an error. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node. status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE. code is the error or warning code. The default is 0. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source specifies the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.
	notifier out returns notifier unchanged.
	notification is the last message the notifier receives. This data type changes to match the subtype of notifier.
	timed out? is TRUE if the notifier does not receive a message before the function times out or if an error occurs.
	error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces. Right-click the error out front panel indicator and select Explain Error from the shortcut menu for more information about the error. status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning.

Wait on Notification Details

Each unique instance of this function remembers the timestamp of the last message it receives.

If ignore previous is FALSE, each instance of the Wait on Notification function waits if the message in the notifier has a time stamp for the same time that the instance of the function last executed. If the message is new, then the function returns the message.

When ignore previous is TRUE, the Wait on Notification function always waits for a new message, even if the message currently in the notifier is one it has never seen before.

If you experience deadlock when you use this function repeatedly with different notifiers, use the Wait on Notification with Notifier History function to store timestamps for each individual notifier. This function prevents deadlock.

This function does not remove the message from the notifier. Although a specific instance of the function returns a message only once, other instances of the function or to the Wait on Notification from Multiple function repeat the message until you call the Send Notification function with a new message.