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Acquires access to a semaphore. Details  

	semaphore is a reference associated with a semaphore.
	ms timeout specifies how many milliseconds the function should wait for the semaphore to become available. The default is -1, indicating never to time out.
	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 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.
	semaphore out has the same value as semaphore.
	timed out is TRUE if the semaphore did not become available before the function timed out or if an error occurred.
	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.

Acquire Semaphore Details

If the semaphore is already acquired by the maximum number of tasks, the VI waits ms timeout milliseconds before timing out. If the semaphore becomes available during the wait, timed out is FALSE. If the semaphore does not become available or semaphore is not valid, timed out is TRUE. The count on a semaphore is incremented each time Acquire Semaphore executes, even if the task acquiring the semaphore has already acquired it once. Acquiring the same semaphore twice without an intervening call to Release Semaphore generally results in incorrect behavior, such as corrupted data values.

This VI attempts to execute even if the error in parameter contains an error.